DCA Calculator
Investing & ReturnsProject dollar-cost averaging over time.
Projected portfolio value: $404,525
What do you want to solve for?
Project your portfolio forward, or work backwards from a goal to the deposit, starting amount, return or time you'd need.
Advanced options
- Invested$125,000
- Gain$279,525
Return & averaging metrics
Goal progress
$95,475 short of your $500,000 goal.
Portfolio value over time
Your invested cash against its market value over the plan, valued at the expected trend price.
- Portfolio value$404,525
- Total invested$125,000
Average cost vs market price
Fixed-dollar buying snaps up more shares when the price dips, pulling your average cost below the price's peaks — the heart of dollar-cost averaging.
- Market price$117.86average
- Your average cost$93.72per share
Average cost summary
What you paid per share against the prices you faced — and how much the averaging discount came to.
| Metric | Investment schedule |
|---|---|
| Starting share price | $50.00 |
| Average share price | $117.86 |
| Average cost / share | $93.72 |
| Projected ending price | $233.05 |
| Total shares | 1,735.80 |
| Discount vs average price | 20.5% |
Invested vs market value
The widening gap between what you've put in and what it's worth.
Shares accumulated
Your share count climbing with every purchase and reinvested dividend.
1,735.80 shares
Where your money ends up
A line-by-line bridge from the cash you invest to your final, spendable value.
- Initial investment+ $5,000
- Recurring contributions+ $120,000
- Total invested$125,000
- Investment growth+ $279,525
- Final value$404,525
DCA vs lump sum
What if you'd invested the same total all at once at the start, instead of averaging in? A lump sum wins when prices climb from day one; averaging in wins when the path dips along the way — and it never needs all the cash up front.
- Dollar-cost averaging$404,525
- Lump sum$868,877
| Metric | Dollar-cost averaging | Lump sum |
|---|---|---|
| Average cost / share | $93.72 | $50.00 |
| Total shares | 1,735.80 | 2,500.00 |
| Projected portfolio value | $404,525 | $868,877 |
Investing the whole amount up front comes out $464,352 ahead here — the price rises from the start, so earlier money buys cheaper. Averaging in still spreads your timing risk and needs no lump up front.
Investment schedule
| Year | Invested | Shares | Value | Gain |
|---|---|---|---|---|
| 1 | $11,000 | 204.77 | $11,058 | $58 |
| 2 | $17,000 | 305.26 | $17,803 | $803 |
| 3 | $23,000 | 426.95 | $26,892 | $3,892 |
| 4 | $29,000 | 541.02 | $36,802 | $7,802 |
| 5 | $35,000 | 627.46 | $46,098 | $11,098 |
| 6 | $41,000 | 710.95 | $56,409 | $15,409 |
| 7 | $47,000 | 810.22 | $69,428 | $22,428 |
| 8 | $53,000 | 904.08 | $83,669 | $30,669 |
| 9 | $59,000 | 977.84 | $97,736 | $38,736 |
| 10 | $65,000 | 1,049.63 | $113,304 | $48,304 |
| 11 | $71,000 | 1,133.24 | $132,115 | $61,115 |
| 12 | $77,000 | 1,213.08 | $152,737 | $75,737 |
| 13 | $83,000 | 1,278.37 | $173,835 | $90,835 |
| 14 | $89,000 | 1,342.44 | $197,150 | $108,150 |
| 15 | $95,000 | 1,415.41 | $224,496 | $129,496 |
| 16 | $101,000 | 1,485.86 | $254,523 | $153,523 |
| 17 | $107,000 | 1,545.84 | $285,982 | $178,982 |
| 18 | $113,000 | 1,605.17 | $320,714 | $207,714 |
| 19 | $119,000 | 1,671.29 | $360,639 | $241,639 |
| 20 | $125,000 | 1,735.80 | $404,525 | $279,525 |
Annual rows show cumulative cash in, shares and market value; the purchases view shows each buy and the running average cost.
How the projection works
Each period you invest a fixed amount at that period's price, so your share count grows fastest when prices are low. The illustrative price path is a steady trend bent by a four-year volatility cycle:
Pₜ = P₀ · (1 + g)^t · (1 + v · sin(2π·t / 4))where:
- Pₜ
- the share price at time t (in years)
- P₀
- the starting share price
- g
- the expected annual return — the drift
- v
- the volatility amplitude (0 = a smooth trend)
- t
- time elapsed, in years
total invested ÷ shares boughtShares bought each period = (amount − fee) ÷ that period's price, so a fixed deposit buys more shares when the price is lower — the averaging effect.
The portfolio is valued over time at the smooth trend price P₀·(1+g)^t — the expected path — so volatility shapes your entry prices and share count, not a lucky or unlucky final price.
Dividends accrue each period on the shares you hold; with DRIP on they buy more shares, otherwise they collect as cash. This is an illustrative model, not a forecast of any real market.
Worked example
The figures below update live with your inputs, so you can read a plain-English summary of the exact plan on screen.
Your plan
Investing $5,000 up front plus $500/month into a $50.00 share for 20 years at a 8% expected return builds about 1,735.80 shares at an average cost of $93.72 each — a projected $404,525.
Input definitions
- Initial investment
- A one-time lump sum invested at the very start, at the starting price.
- Recurring investment
- The fixed amount you invest every period — the steady stream that does the averaging.
- Starting share price
- The price per share on day one; every share count is measured against the moving price from here.
- Expected annual return
- The average yearly price growth that sets the trend the price follows.
- Price volatility
- How far the price swings above and below the trend along the way — the source of DCA's buy-low advantage.
- Average cost per share
- Total cash invested divided by the shares it bought — what you actually paid on average.
- Dividend yield
- Annual dividends as a percent of price; reinvested into shares (DRIP) or taken as cash.
- Per-purchase fee
- A fee charged on each buy, so frequent small purchases pay it more often.
Know what this estimate is based on
- Jurisdiction
- General mathematical model
- Scope and limitations
- Scenario model, not a forecast. Returns, volatility, inflation, fees, and taxes are assumptions and actual investment outcomes can be lower or negative.
- Source links checked
- Jul 30, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
How to use
- 01
Choose what to solve for: project your portfolio's value, or work backwards from a goal balance to the deposit, starting amount, return or number of years you'd need.
- 02
Enter an initial investment and a recurring amount, set how often you invest — weekly, biweekly, monthly, quarterly or yearly — then give the starting share price, your expected annual return and how much the price swings (volatility).
- 03
Open Advanced for a dividend yield with reinvestment, a per-purchase fee, a tax rate and inflation, then read the projected value, the average cost per share, the return metrics and the DCA-versus-lump-sum verdict, plus the growth, average-cost and share charts and the full schedule.
- 04
Save scenarios to compare plans side by side, export the schedule to CSV or Excel, or copy a share link that reopens the exact projection.
Formula
Shares bought each period = (cash contribution − purchase fee) ÷ purchase price. Total shares = initial shares + recurring-purchase shares + DRIP shares. Final value = total shares × projected ending price + any dividends taken as cash. The illustrative purchase path is price(t) = P₀ × (1 + g)ᵗ × (1 + v × sin(2πt ÷ 4)); the final valuation uses the smooth trend price P₀ × (1 + g)ᵗ.
Example
With no initial lump sum, invest 500 at the end of every month for one year. If the share price stays at 100, fees and dividends are zero, each purchase buys 5 shares. Twelve purchases invest 6,000 and accumulate 60 shares worth 6,000.
Definitions
- Dollar-cost averaging
- Investing the same cash amount on a schedule, which buys more shares at lower prices and fewer at higher prices.
- Average cost
- Cash invested in purchases divided by the number of shares those purchases acquired.
- Trend price
- The smooth expected price path used to value the ending portfolio.
- Volatility path
- The reproducible four-year price oscillation used to vary purchase prices; it is illustrative, not a forecast.
- DRIP
- Dividend reinvestment: using net dividends to purchase additional shares.
Good to know
What dollar-cost averaging really is
Dollar-cost averaging is the simple discipline of investing a fixed sum of money on a fixed schedule, no matter what the price happens to be that day. Instead of trying to pick the perfect moment to buy, you commit to, say, $500 every month and let the calendar make the decision for you. The quiet genius of the approach is hidden in the arithmetic of buying a fixed dollar amount rather than a fixed number of shares: when the price is low your $500 picks up more shares, and when the price is high it picks up fewer. Without any cleverness on your part, you automatically buy more when things are cheap and less when they are expensive, which is the opposite of what most investors do when they let emotion drive their timing. This calculator is built around that mechanism. It does not simply grow a single balance at an assumed rate the way a savings projection does; it actually counts the shares you accumulate at each purchase, tracks the blended price you paid for them, and values the resulting pile at the end. The default plan on screen — a $5,000 head start, then $500 a month for twenty years into a stock that begins at $50 and is expected to return 8% a year — turns $125,000 of your own contributions into roughly $404,500, having quietly assembled about 1,736 shares along the way. Everything else the tool shows, from the average-cost line to the lump-sum comparison, exists to make the consequences of that one simple habit visible. The strategy will not guarantee you the best possible outcome, but it removes the hardest and most error-prone part of investing — deciding when to act — and replaces it with a rule you can actually keep.
How this calculator models price and purchases
To show averaging in action, the tool needs a moving price rather than a single growth rate, so it builds one from three of your inputs. The starting price anchors where the journey begins, your expected annual return sets the underlying trend the price drifts along, and the volatility setting bends that trend up and down with a smooth, repeating four-year cycle. The exact path is shown in the formula section, but the idea is intuitive: the price climbs over the years roughly as your expected return suggests, while wobbling above and below that line on the way. At every purchase the calculator reads off the price at that moment, subtracts any per-purchase fee, and divides what is left by the price to find how many shares the deposit bought — fractions included. It does this for your initial lump at the very start and then for every scheduled contribution, weekly through yearly, accumulating the share count as it goes. One deliberate design choice is worth understanding: although purchases happen at the wobbly path price, the final portfolio is valued at the smooth trend price, the 'projected ending price' shown in the results. That keeps the headline honest, because it means the volatility you set affects how cheaply you accumulated shares — the thing dollar-cost averaging is actually about — without secretly handing you a lucky high price or punishing you with an unlucky low one on the single day the projection happens to end. The whole construction is deterministic and reproducible: the same inputs always give the same answer. Treat it as a clear illustration of how a steady plan behaves under a chosen set of assumptions, not as a prediction of what any particular market will really do, because real prices are far messier than any tidy cycle.
Why your average cost beats the average price
The single most important number this calculator produces is the average cost per share, and it is almost always lower than the average price over the same period — a result that surprises people until they see why. Suppose over four buys the price is $150, then $100, then $50, then $100, and you invest $100 each time. The plain average of those prices is $100, but your $100 deposits bought 0.67, 1.0, 2.0 and 1.0 shares respectively, for 4.67 shares in total, and $400 spread over 4.67 shares is an average cost of about $85.71. You paid less per share than the average price because your fixed dollars bought a bigger slug of shares during the cheap stretch. Mathematicians call your average cost the harmonic mean of the prices, and a basic inequality guarantees the harmonic mean is never greater than the ordinary average, and is strictly lower whenever the prices differ at all. That is why the effect shows up even on a smoothly rising market with no volatility — any variation in price is enough. On the default plan the average price you bought at was about $117.86, while your average cost came out to just $93.72, a meaningful discount baked in purely by the mechanics of buying fixed amounts. The average-cost-versus-price chart draws both lines so you can watch the gap open up, and a small caveat is worth keeping in mind: a lower average cost is a genuine advantage over your own buying pattern, but it is not the same as beating the market or beating a lump sum, which are separate questions the next sections take up.
Volatility: where the buy-low advantage comes from
Volatility is the setting that controls how much the price swings around its trend, and it is the lever that turns dollar-cost averaging from a mere convenience into a real edge on your purchase price. With volatility at zero the price marches smoothly from its start to its projected end, and while your average cost still lands a little below the average price thanks to the harmonic-mean effect, the advantage is modest. Crank volatility up and the path develops real dips, and because your fixed deposits buy aggressively into those dips, your share count swells and your average cost falls further. The cleanest way to see this is to set the expected return to zero, so the trend is flat and the price simply oscillates around the starting figure, then raise volatility: the average cost drops below the starting price as cheap shares accumulate, and the plan ends with a gain even though the price went nowhere on average. That is the famous buy-low behaviour of dollar-cost averaging in its purest form — you profit from the bumps themselves. It is important to be clear-eyed about what volatility does and does not do here. It shapes the prices at which you buy and therefore the number of shares you own, but the calculator deliberately values those shares at the end using the smooth trend price, so a higher volatility setting does not inflate your final number by gifting you a fortunate closing price. Real markets are of course nothing like a tidy sine wave, but the lesson the model teaches is sound and durable: a saver who keeps investing through turbulence accumulates shares cheaply, while one who stops buying when prices fall throws that advantage away precisely when it is largest.
DCA versus a lump sum: the honest comparison
A question that follows naturally is whether spreading your money in actually beats putting it all to work at once, and the answer the calculator gives is refreshingly honest: usually not, when prices rise steadily. The DCA-versus-lump-sum panel compares your averaging plan against a hypothetical in which the same total capital is invested up front at the starting price and left to ride. Because investing everything on day one means buying at the lowest price the trend ever offers, the lump sum on the default rising-market path reaches about $868,877, comfortably ahead of the roughly $404,525 from averaging in. This is not a flaw in dollar-cost averaging; it is a direct consequence of markets tending to rise over long horizons, which is exactly why studies repeatedly find that investing a windfall immediately beats trickling it in most of the time. Averaging in pulls ahead in the cases where the price spends real time below where it started — a market that falls and later recovers, or one that simply chops sideways — because those are the conditions that let your fixed deposits harvest cheap shares. But the comparison also misses the point for most people, and the tool is careful to say so. Hardly anyone has twenty years of contributions sitting in cash on day one; the realistic choice is between investing each paycheque as it arrives or leaving it idle, and against that baseline averaging in is simply the act of investing at all. Its true value is not out-performance but risk reduction and behaviour: it removes the gut-wrenching possibility of committing everything just before a crash, and it converts the impossible task of perfect timing into an automatic habit you can sustain for decades.
Working backwards from a goal
Planning rarely runs in only one direction. Quite often you already know the figure you are chasing — a house deposit, a number that spells retirement, a college fund — and what you actually need is the missing piece that gets you there. The tool's reverse modes exist for precisely this. Leave it on 'Project value' to run your plan forward, or switch to one of the four backward modes that begin from a goal balance and hand you back the input you left open: 'Required deposit' sizes the recurring amount to invest, 'Required start' the upfront lump, 'Required return' the yearly growth your plan quietly leans on, and 'Time needed' how many years the journey takes. The value of this is practical rather than academic. Curious what reaching half a million would ask of you? Pick 'Required deposit', type in the target, and the monthly figure your assumptions imply appears at once — a blunt but useful test of whether the plan survives contact with your real budget. Suspect a target might be wishful? Solve for the return instead and weigh the rate it asks of you; if the answer comes back near 15% a year, that is the calculator nudging you to trim the goal, grant it more time, or set aside a little more each month before reaching for riskier bets. Whichever blank you fill, the projection beneath it is the same plan seen from the other end, and every backward mode is candid about impossibility: when not even a heroic return or a full century of buying would close the gap, it says so outright rather than printing a comforting fiction. Used this way the solver turns into a sounding board for whether a dream is fundable at all, what it really costs per paycheque, and how much extra patience the remainder demands.
Dividends and reinvestment
Many of the assets people dollar-cost average into — index funds, dividend stocks, broad ETFs — pay income along the way, and the calculator models this with a dividend yield and a reinvestment switch. Each period your existing shares earn a dividend based on the yield and the current price, and you choose what happens to that cash. With reinvestment, often called a DRIP for dividend reinvestment plan, the dividends immediately buy more shares at the going price, so your share count compounds on top of your own contributions and the next dividend is calculated on a slightly larger holding. With reinvestment turned off, the dividends accumulate as a separate cash pile that sits alongside your shares rather than growing them. The difference is not trivial over decades: on the default plan a 2% reinvested yield quietly added roughly 402 extra shares and about $56,000 of dividends across the twenty years, a meaningful slice of the final value that came from income rather than price growth. Reinvesting is usually the more powerful choice for long-term wealth building precisely because it keeps every dollar of income working and compounding, but taking dividends as cash can make sense when you need the income to spend. Tax treatment matters too, and the calculator handles it realistically: dividends are taxed as income in the year you receive them, which slightly reduces how much gets reinvested, while the growth in your share price is left to compound untouched until the end. That split mirrors how most tax systems actually treat investment income and capital gains, and it is why holding dividend-paying investments inside a tax-sheltered account can make such a large difference over a lifetime of reinvestment.
Fees, taxes and inflation: what you actually keep
The projected value at the top of the page is a gross, nominal figure, and three deductions sit between it and the money you can genuinely spend — each one adjustable here. Fees come first, and they bite unusually hard on averaging in, because a strategy founded on frequent small purchases pays the charge over and over again. The fee is skimmed off every deposit before a single share is bought, so you finish with fewer shares and a marginally higher average cost than a fee-free version of the same plan; on a weekly cadence those tiny nibbles compound into real money. Tax arrives next, and the calculator models it the way it genuinely shows up rather than as one crude haircut. Dividends count as income and are taxed in the year they land, shrinking the amount available to reinvest, while the profit on your shares is left undisturbed to grow and is taxed only at the finish line, and only when there is a gain — a position sitting at a loss owes nothing. Apply a 15% rate to the default plan and the after-tax line settles well below the gross total, with the step bridge spelling out where each slice went. Inflation is the third deduction and the most insidious, because it leaves the dollar figure on the page untouched while quietly hollowing out what those dollars will buy. Switch it on and a 'value in today's money' figure appears beside a real line on the chart, restating that far-off total in present-day spending power. Together the three argue for one simple discipline: look at what survives tax and inflation rather than the gross sticker number, hold low-cost investments wherever you can, lean on tax-sheltered accounts when they are available, and pick a return assumption with enough headroom over inflation that the plan still means something once prices have climbed — a return that merely ties inflation is a slow loss wearing the costume of a gain.
Reading the return metrics
The results panel reports several different numbers about return, and they answer genuinely different questions, so it pays to know which is which. The total return is the simplest: your total gain divided by everything you put in, expressed as a percentage — on the default plan, turning $125,000 into about $404,500 is a total return of roughly 224%. But that figure says nothing about how long it took or that the money went in gradually, so on its own it can mislead. The annualized return fixes both problems. It is a money-weighted return, meaning it accounts for the fact that your early contributions were invested far longer than your recent ones, and it reports the answer as the one constant yearly rate that, applied to your actual schedule of deposits, would have produced your final value. For the default plan that works out to about 10.2% a year, which is higher than the 8% price trend because the reinvested 2% dividend is part of your total return — a useful reminder that income and price growth together drive your result. The average cost per share and the average price sit alongside these as the metrics specific to averaging in: together they show how much your disciplined buying improved on the typical price you faced. Read these figures as a set rather than fixating on any one. The total return flatters a long plan, the annualized return is the fairer measure of the rate you actually earned, and the average-cost numbers reveal the mechanical edge of the strategy itself — and none of them, on its own, tells the whole story of whether a plan is working.
Strategy, real examples and common mistakes
Pull the threads together and a short, durable rulebook for averaging in takes shape. Begin as soon as you reasonably can and put the buying on autopilot, because the habit outweighs the timing and automation spares you from arguing with the market every single month. Keep going through the rough patches rather than freezing when prices slide, since those cheap stretches are exactly when fixed deposits do their finest work and rack up the most shares. Nudge your contributions higher as your pay grows, let dividends reinvest while you are still in the building phase, hold costs down, and gauge success by what you keep once tax and inflation have taken their share. A handful of concrete numbers sharpen the point: the default plan converts $125,000 of contributions into roughly $404,500, of which about $56,000 is reinvested dividends; dial the trend down to zero while leaving volatility high and you can watch averaging in actually edge out a lump sum, whereas on a steadily climbing path the lump sum pulls ahead — vivid proof that the strategy buys protection from bad timing, not a promise of beating the market. The errors that trip investors up are simply these good habits turned upside down. They stop buying when the market drops and hand back the discount; they expect averaging in to outrun the index and feel cheated when a rising market rewards the lump sum instead; they shrug off the per-trade fees that gnaw at frequent purchases; they quote a gross future total and forget what tax and inflation will claim; and they mistake a neat projection for a guarantee rather than a sketch built on one set of assumptions. Lean on this tool to explore a spread of outcomes instead of fixating on a single hopeful number, give the money room and time, automate the discipline, and let the quiet arithmetic of buying steadily — in fair weather and foul — do the patient work it was built for.
Frequently asked questions
What does this calculator actually model?
It buys shares, not an abstract balance — which is the whole point of dollar-cost averaging. Each period it invests your fixed amount at that period's price, so a low price buys more shares and a high price fewer, and it tracks the share count, the average cost and the portfolio value period by period. The price follows a steady trend set by your expected return, gently bent by an illustrative four-year volatility cycle. It is a reproducible teaching model of how averaging in behaves, not a Monte-Carlo simulation or a forecast of any real market.
Why is my average cost per share below the average price?
Because you invest a fixed dollar amount, not a fixed number of shares. The same $500 buys more shares when the price is low and fewer when it is high, so cheap periods carry extra weight in your final share count and drag the blended cost down. Mathematically your average cost is a harmonic mean of the prices you paid, which is always at or below their plain average. On the default plan the average price worked out to about $117.86, but the average cost was just $93.72 — and this gap appears for any varying price, even a smooth rise; it is not a special effect of volatility.
What does each 'solve for' mode actually do?
Project value runs your plan forward to a final portfolio value. The remaining four begin from a goal balance and hand back whichever input you left open: 'Required deposit' sizes the recurring amount, 'Required start' the upfront lump, 'Required return' the yearly growth the plan leans on, and 'Time needed' the years it takes. When a goal is unreachable — beyond any sensible return, or further off than a century of buying — the calculator tells you outright rather than printing a figure that simply can't happen.
Does dollar-cost averaging beat investing a lump sum?
Not usually when prices rise steadily — and that is the honest result, not a knock on the strategy. Investing everything at the start buys at the lowest price, so on the default rising-market path the lump sum reaches about $868,877 while averaging in reaches about $404,525. Averaging in pulls ahead when the price spends time below where it started — choppy or falling-then-recovering markets — and, crucially, it works with money you earn over time rather than a fortune you'd need on day one. Its real value is removing the risk of investing everything right before a drop, and turning saving into a habit. The DCA-versus-lump-sum panel shows which wins on your chosen path.
What does the volatility setting change?
It sets how far the price swings above and below its trend on the way to the projected ending price. Higher volatility means deeper dips for your fixed deposits to buy into, which lowers your average cost — set the expected return to 0% and raise volatility and you can watch the average cost fall below the starting price as cheap shares pile up. Volatility shapes the prices you buy at and the shares you end up with; the portfolio is always valued at the smooth expected trend price, so the swings never hand you a lucky or unlucky final number.
How are dividends and reinvestment handled?
Each period your shares earn a dividend equal to the yield divided by how often you invest, based on the current price. With reinvestment (DRIP) on, that cash immediately buys more shares, so your share count compounds; with it off, the dividends collect as a separate cash pile. On the default plan a 2% reinvested yield added about 402 extra shares and roughly $56,000 of dividends over the 20 years. Dividends are taxed as income when received, separately from the capital-gains tax applied to your price growth at the end.
How do fees and taxes affect the result?
The fee is charged on every purchase, so a plan with frequent small buys pays it more often — it comes straight off each deposit before shares are bought, leaving you with fewer shares and a higher average cost. Tax is split the way real investing works: dividends are taxed as income in the year you receive them, while the gain on your shares is taxed only at the end, and only if it's positive. The step-by-step bridge and the after-tax figure show exactly how much each one takes.
Is the projected value in today's money?
By default it's nominal — the literal dollar figure years out, which will buy less than the same sum does today. Turn on an inflation rate under Advanced and the calculator adds a 'value in today's money' figure that discounts the result, along with a real line on the growth chart. An impressive headline total can still translate into a modest standard of living once rising prices are accounted for, so the real, post-tax figure is the one that actually tells you whether the plan gets you where you're going.