Student Loan Calculator
Loans & MortgagesRepay your studies on schedule.
Loan details
Enter a loan amount to begin.
Advanced options
Unsubsidized loans accrue interest while you study and during grace; subsidized loans don't.
Enter a loan amount to begin.
How this is calculated
- 1Interest accrued in deferment + grace, capitalized: $0 × 0.000%/mo × 0 mo = $0
- 2Balance at repayment = principal + capitalized interest: $0 + $0 = $0
- 3Monthly rate i and number of payments n: i = 0.0000%, n = 0
- 4Scheduled payment = B × i × (1+i)ⁿ ÷ ((1+i)ⁿ − 1): $0 → $0
- 5Total interest = capitalized + scheduled interest = $0; total repaid = $0
Formulas
| Metric | Formula | Your value |
|---|---|---|
| Monthly payment | B × i × (1+i)ⁿ ÷ ((1+i)ⁿ − 1) | $0 |
| Capitalized interest | Principal × monthly rate × (deferment + grace) | $0 |
| Total interest | Capitalized interest + Σ monthly interest | $0 |
| Total repaid | Principal + total interest | $0 |
| Interest vs principal | Total interest ÷ principal | 0.0% |
Your inputs
| Input | What it is | Your value |
|---|---|---|
| Loan amount | Amount borrowed (principal) | $0 |
| Interest rate | Annual interest rate on the loan | 0.00% |
| Repayment term | Years to repay on the standard plan | 0 mo |
| Loan type | Subsidized loans accrue no interest in school | Unsubsidized |
| Grace period | Months before the first payment is due | 0 mo |
Know what this estimate is based on
- Jurisdiction
- General model; U.S.-specific rules are identified on the relevant tool
- Scope and limitations
- Educational estimate only. A lender may use different compounding, day-count, eligibility, tax, insurance, escrow, fee, or rounding rules.
- 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
Enter the amount you borrowed, the annual interest rate, and the years you plan to take to repay — the scheduled monthly payment, total interest and payoff time update instantly.
- 02
Open Advanced to choose subsidized or unsubsidized, add any in-school deferment and grace-period months (the tool capitalizes the interest an unsubsidized loan accrues before repayment), and enter your income for an affordability read.
- 03
Add an extra monthly payment to see the time and interest it saves, then compare the standard, graduated, extended and income-based plans and the fixed-versus-variable rate race below.
Formula
The calculator works in two stages: it first capitalizes any interest that builds up before repayment, then amortizes the resulting balance. While an unsubsidized loan sits in in-school deferment or its grace period, interest accrues as principal × monthly rate × those months, and that amount is folded into — capitalized into — the balance when repayment begins. Subsidized loans skip this entirely: the lender pays that interest, so repayment starts on exactly what you borrowed. Call the balance at repayment B, the monthly rate i = annual rate ÷ 12, and n = term in years × 12. The scheduled payment is M = B × i × (1 + i)^n ÷ ((1 + i)^n − 1); if the rate is 0 it collapses to M = B ÷ n, so there is never a divide-by-zero. Each month interest of balance × i is charged and only the remainder of M reduces principal, which is why the early payments barely move the balance. Total interest is every monthly interest charge plus the capitalized amount, and total repaid is principal plus total interest. At the defaults — 30,000 borrowed at 6.5% over 10 years, unsubsidized with a 6-month grace — the monthly rate is 0.5417%, n is 120, 975 of interest capitalizes so repayment starts on 30,975, and M works out to about 352 a month for roughly 12,210 in total interest. An extra monthly payment does not change M; it is applied entirely to principal, re-amortizing the loan to clear early, and the interest saved is the gap between the original interest and the interest on the faster payoff. The repayment-plan comparison runs the same balance through different payment shapes, and the fixed-versus-variable section re-amortizes it at a rate that resets each year so you can see what a drifting rate costs.
Example
Take the defaults: you borrow 30,000 at 6.5% over 10 years, the loan is unsubsidized, and there is a 6-month grace period before repayment starts. First the capitalization. During those 6 grace months interest accrues at 30,000 × (6.5% ÷ 12) = 30,000 × 0.5417% = about 162.50 a month, totalling 975, which is added to the balance — so repayment begins not on 30,000 but on 30,975. Now the amortization: the monthly rate is 0.5417% and the term is 10 × 12 = 120 payments, giving a level monthly payment of about 352. Across all 120 months you repay roughly 42,210, of which 30,000 is the money you borrowed and about 12,210 is interest — the 975 that capitalized plus about 11,235 charged over the schedule — so interest adds around 41% on top of what you borrowed. The front-loading is clear in the first month: interest alone is 30,975 × 0.5417% = about 168, so a little under half of that first 352 payment touches principal. After a full year of payments the balance has fallen only to about 28,700. The lever that changes this is the extra payment: add 100 a month straight to principal and the loan clears well before the 120th month, erasing a large slice of that 12,210 interest bill. Had the loan been subsidized instead, no interest would have accrued in school or grace, repayment would start on the original 30,000, and the total interest would be lower.
Definitions
- Loan amount (principal)
- The amount you actually borrowed, before any future or capitalized interest — the figure the repayment schedule amortizes once any pre-repayment interest is added.
- Interest rate
- The nominal annual rate on the loan, divided by 12 to get the monthly rate applied to the outstanding balance each month.
- Repayment term
- How many years you take to clear the loan on the standard plan; multiplied by 12 it sets the number of monthly payments, n.
- Subsidized vs unsubsidized
- On a subsidized loan the lender pays the interest while you study and during grace, so nothing is added. On an unsubsidized loan that interest accrues and is capitalized into your balance.
- Capitalized interest
- Interest that built up during in-school deferment and the grace period and is folded into the principal when repayment starts, so you then pay interest on it too.
- Grace period
- The months after you leave school before the first payment is due — typically around six. On unsubsidized loans interest still accrues during it.
- Monthly payment
- The level scheduled amount that covers each month's interest plus principal and retires the balance exactly at the end of the term — the headline result.
- Extra monthly payment
- An optional amount paid above the scheduled payment, applied entirely to principal, so the loan clears early and the lifetime interest falls.
Good to know
Subsidized versus unsubsidized loans and how interest capitalizes
Federal student loans come in two main flavors that behave very differently before you ever make a payment, and the distinction quietly shapes the balance you eventually type into this calculator. On a subsidized loan, the government pays the interest that accrues while you are enrolled at least half-time, during the grace period after you leave school, and through approved deferments. That means the balance you graduate with equals the amount you actually borrowed — nothing has been added. An unsubsidized loan, by contrast, accrues interest from the day it is disbursed, including every month you sit in class. You are not required to pay that interest while studying, but it does not vanish; it accumulates in the background. When repayment begins, any unpaid accrued interest is capitalized, meaning it is folded into your principal and becomes part of the balance on which all future interest is charged. From that moment you are paying interest on interest, and the loan starts larger than the sum you were handed. This is why so many borrowers are startled to see a starting balance noticeably above their original loan amount. A four-year degree financed with unsubsidized loans can capitalize a meaningful chunk of interest before the first bill arrives. The practical lessons are concrete: prioritize subsidized loans when you qualify for them, and if you hold unsubsidized debt, consider paying at least the accruing interest while still in school, which prevents capitalization and keeps the principal from inflating. Even modest interest-only payments during your studies can shave thousands off the balance that the amortization schedule here will later grind through, because every dollar of interest you stop from capitalizing is a dollar that never compounds against you for the next decade.
Grace periods, deferment, and forbearance after you leave school
Student loans are unusual among debts in giving you several built-in ways to pause or postpone payments, and understanding them helps you read the balance this calculator amortizes. Most federal loans include a grace period, typically around six months after you graduate, leave school, or drop below half-time enrollment, before the first payment is due. That window exists to let you find work and organize your finances. Beyond the grace period sit two further pauses. Deferment lets you temporarily stop payments for qualifying reasons such as returning to school, unemployment, or economic hardship; crucially, on subsidized loans the government usually keeps covering the interest during deferment, so the balance does not grow. Forbearance is a more flexible pause that servicers can grant when you are struggling but do not qualify for deferment, yet it carries a sharper edge: interest accrues on every loan during forbearance, subsidized or not, and that interest typically capitalizes when the forbearance ends, enlarging your principal. These tools are genuine safety valves that can prevent default during a rough stretch, and using them is far better than missing payments. But they are not free time. A long forbearance can quietly add a substantial sum to the balance you eventually repay, lengthening the schedule and lifting the total interest the calculator reports. The disciplined approach is to treat deferment and forbearance as short-term bridges rather than long-term solutions, to pay the accruing interest during the pause if you possibly can so it never capitalizes, and to return to active repayment as soon as your situation stabilizes. Knowing which protections your loans carry, and what they cost, lets you use them deliberately instead of drifting into a larger balance by default.
Standard amortized repayment versus income-driven plans
The number this calculator produces is the standard-plan payment: a fixed monthly amount, computed by amortization, that retires your balance in equal installments over the term you select. It is the default for most federal loans and almost always the path that costs the least in total interest, because it clears the debt fastest and never lets the balance drift upward. The trade-off is that the payment is set by the math, not by your wallet, so a large balance on a short term can produce a figure that strains an entry-level salary. That is the gap income-driven repayment is designed to fill. Income-driven plans recalculate your payment each year as a percentage of your discretionary income rather than as whatever it takes to clear the loan on schedule. When your earnings are low, the payment falls, sometimes dramatically, and in hard times it can drop close to nothing. The relief is real, but it comes with consequences this calculator deliberately does not assume. Because the payment is no longer tied to the amortization schedule, it can be less than the monthly interest, in which case the balance actually grows even as you pay — the opposite of the steady decline shown here. Income-driven plans also stretch repayment over a much longer horizon, often twenty years or more, and any balance remaining at the end may be forgiven, though that forgiven amount can carry its own tax treatment. The right way to use the two together is to read the standard payment here first as the benchmark and the cheapest route, then turn to an income-driven estimate only if that benchmark genuinely does not fit your income. Choosing an income-driven plan out of preference rather than necessity usually means paying far more interest over a far longer life than the schedule in front of you would.
Federal versus private loans and the protections that differ
Two loans can carry an identical balance, rate, and term — producing the exact same payment in this calculator — and yet be worlds apart in everything that happens when life does not go to plan. That difference comes down to whether the loan is federal or private. Federal student loans are issued by the government and come wrapped in a thick layer of borrower protections: access to income-driven repayment, generous deferment and forbearance options, fixed rates set by statute, and eligibility for forgiveness and discharge programs. Many also offer the subsidized interest treatment described earlier. Private student loans, issued by banks and other lenders, are ordinary consumer credit by comparison. Their rates may be fixed or variable and are priced on your credit and often a cosigner's, they rarely offer income-driven plans, their hardship options are limited and discretionary, and they are generally excluded from federal forgiveness programs. The calculator treats both the same because the amortization math is identical, but the safety net beneath them is not. The practical guidance that flows from this is well established: exhaust federal options before turning to private loans, because the protections are worth far more than a marginally lower advertised rate when your income is uncertain in the years after graduation. If you do hold private debt, recognize that you have fewer escape routes if you lose your job or face a medical crisis, which is an argument for keeping a larger emergency cushion and for paying that debt down faster when you can. Knowing exactly which of your loans are federal and which are private — and never assuming a private loan behaves like a federal one — is one of the most important pieces of information a borrower can have, because it determines what tools you will have available if repayment ever becomes hard.
Refinancing student debt and the federal benefits you give up
Refinancing replaces one or more existing student loans with a brand-new loan from a private lender, usually pitched on the promise of a lower interest rate. The arithmetic of why a lower rate helps is exactly what this calculator shows: drop the rate and the total interest falls, sometimes substantially over a ten-year payoff. For a borrower with strong income and good credit, refinancing can genuinely save real money, and consolidating several loans into one can simplify a tangle of servicers and due dates. But student-loan refinancing carries a cost that does not appear in the payment figure and that many borrowers discover too late. When you refinance federal loans into a private one, those federal protections are gone permanently and cannot be restored. You forfeit income-driven repayment, so the option to tie your payment to your income disappears. You give up the federal deferment and forbearance framework, leaving only whatever limited hardship terms the private lender chooses to offer. And you lose eligibility for federal forgiveness and discharge programs, which can be worth a great deal to anyone whose career might qualify. This is why the honest way to weigh a refinance is never to compare rates alone. Ask first whether you might ever need the protections you would surrender: is your income stable, is your field one that could lead to forgiveness, do you have the savings to ride out a job loss without a payment pause? If the answer points to security, the lower rate may be worth it; if it points to uncertainty, the federal safety net is usually the better deal even at a higher rate. Note too that refinancing into a fresh long term resets the amortization clock, returning you to the interest-heavy early years, so a lower rate on a longer term can still raise the total you repay. Compare the full remaining cost of keeping your loans against the full cost of the new one, not just the headline rates.
Loan forgiveness and discharge programs
Beyond simply repaying what you owe, federal student loans offer routes by which part or all of the balance can be cancelled, and these programs are valuable enough that they should shape how you manage the debt long before you reach them. The best known ties forgiveness to public-service careers: after a set number of qualifying monthly payments made while working full-time for an eligible government or nonprofit employer, the remaining balance is cancelled. Income-driven repayment plans carry their own forgiveness, wiping out whatever balance survives at the end of their long term, which is why a payment that runs below the interest charge is not always the disaster it would be on a standard plan. There are also discharge provisions for specific circumstances — total and permanent disability, the closure of the school you attended, or certain cases of borrower defense — that can eliminate the debt entirely outside any repayment count. The reason these matter to anyone using this calculator is that they change the optimal strategy in ways the raw amortization math does not capture. If you are genuinely pursuing forgiveness, aggressively overpaying your loan to clear it early can be counterproductive, because every extra dollar you pay is a dollar that would otherwise have been forgiven; the rational move there is to pay the minimum that keeps you qualified and let the program absorb the rest. Conversely, if forgiveness does not apply to your situation, the standard schedule and well-timed extra payments shown here are exactly the right approach. The programs are notoriously detailed in their requirements — the type of loan, the type of plan, the employer, and the precise payment count all matter — so the essential habit is to confirm your eligibility and track your qualifying payments carefully rather than assuming you will benefit. Knowing whether forgiveness is realistically in your future tells you whether to attack the balance or to manage it patiently.
The outsized power of extra principal-only payments on a long term
Because interest is always charged on the balance still outstanding, any amount you pay above the scheduled figure goes straight to principal and permanently deletes all the future interest that principal would have generated. On a debt as long-lived as a student loan, this lever is remarkably strong, and the calculator's advanced extra-payment field exists to make it visible. The reason the effect is so large is the front-loaded structure shown in the worked example: at the defaults, a full year of payments brings the 30,975 starting balance down only to about 28,700, so the early years still carry years of future interest that an extra payment can wipe out in one stroke. A dollar paid toward principal today does not merely shorten the loan by a dollar; it cancels every interest charge that dollar would have attracted across the remaining years. That is why overpayments early in the term save far more than the same dollars paid near the end, when little interest remains to erase. There are several practical ways to harness this: add a fixed sum to every payment, throw an annual bonus or tax refund at the balance, or round each payment up to the next convenient figure. On federal loans there is a specific trap to avoid. Servicers will, by default, often treat an overpayment as advance payment of your next scheduled bill, which pushes your due date forward but saves no interest at all. To capture the benefit you must instruct the servicer, usually in writing, to apply any extra amount to the principal of the current balance. It is also worth weighing overpayment against your priorities: if you are chasing forgiveness, overpaying forfeits money that would have been cancelled, and if you carry higher-rate debt or lack an emergency fund, those come first. But where none of those apply, paying extra principal on a long student loan is one of the highest-certainty returns available, equal to the loan's interest rate, with no risk attached.
Sizing the payment against your salary and post-graduation debt-to-income
The most consequential decision about student debt is made before any of it is borrowed: how much to take on relative to the income the degree is likely to produce. The calculator turns a balance, a rate, and a term into a concrete monthly payment, and that payment is the figure to test against your expected earnings rather than against a vague sense that the degree will pay off. A widely used rule of thumb holds that total student-loan payments should stay under roughly ten to fifteen percent of your gross monthly income once you start working, which keeps the debt from crowding out rent, savings, and ordinary life. Working backward from that share gives a sober ceiling on how much you can responsibly borrow for a given career. The default payment of about 352 a month, for instance, sits within a healthy share of a typical graduate income; if your field is unlikely to support the payment your balance implies, the balance is too large for the plan, and the affordability gauge will say so. Lenders apply the same logic from the other side through your debt-to-income ratio, the share of your income consumed by all debt payments combined. A heavy student-loan payment eats into that ratio and can shrink what you are later able to borrow for a car or a home, which is why student debt taken on lightly can constrain major life decisions for years. The disciplined sequence is to estimate the starting salary your path actually pays, work out what payment that salary can absorb at a healthy share, and let that figure cap the balance rather than borrowing whatever is offered and hoping the income follows. Stretching the term lowers the payment but, as the schedule makes plain, raises the total interest, easing the monthly strain at a lasting cost. Treating the payment here as a constraint to plan around, not a bill to react to later, is what keeps a degree an investment rather than a burden.
Frequently asked questions
Why is my balance bigger when repayment starts than the amount I borrowed?
On unsubsidized loans interest accrues while you are still in school and during the grace period, and that unpaid interest is capitalized — added to your principal — once repayment begins. From that point you pay interest on interest, which is why the starting balance can exceed what you first received. Set the loan to unsubsidized with deferment or grace months and the calculator shows exactly how much capitalizes; switch it to subsidized and that figure drops to zero, because the lender covers the interest in those periods.
What's the difference between subsidized and unsubsidized loans here?
It changes whether interest builds before repayment. On a subsidized loan the lender pays the interest while you study and during grace, so repayment starts on exactly what you borrowed. On an unsubsidized loan that interest accrues and capitalizes, enlarging the balance the schedule then charges interest on. Everything downstream — the monthly payment, total interest and payoff time — flows from that starting balance, so the toggle can move the headline numbers noticeably.
How do the standard, graduated, extended and income-based plans differ?
They are different payment shapes on the same balance. Standard is a level payment that clears the loan on schedule and costs the least total interest. Graduated starts lower and steps up every couple of years, easing early budgets but adding interest. Extended stretches the term to lower the payment further, at the cost of much more interest. Income-based caps the payment near a tenth of your income; it can be the most affordable month to month but the slowest and most expensive, and if the payment can't cover interest the balance grows until any remainder is forgiven.
Is a fixed or a variable rate cheaper?
It depends on how far the variable rate drifts. A variable rate often starts below a fixed one, but it can rise each year up to a cap. The fixed-versus-variable section re-amortizes your balance at a rate that resets annually and compares the lifetime interest against the fixed loan, so you can see whether the early discount outweighs the later increases. As a rule, a fixed rate buys certainty; a variable rate is a bet that rates stay low.
How much does an extra monthly payment actually save?
Every unit you pay above the scheduled amount goes straight to principal and erases all the future interest that money would have generated, so even small overpayments clear the loan early and cut the total interest. The effect is largest in the early years when the balance is highest. One caution on federal loans: tell your servicer in writing to apply extra amounts to principal rather than advancing your next due date, or the overpayment saves you nothing.
Is the payment affordable on a normal starting salary?
Enter your expected gross income and the affordability gauge compares the payment against it. A widely used guideline is to keep total student-loan payments under about 10 to 15 percent of gross monthly income, so the gauge flags anything above that as a stretch. If the payment is too high, lengthening the term lowers it but raises total interest, while an income-based plan ties it directly to what you earn. Checking the payment against your likely income before you borrow more is the best guard against an unmanageable balance.
Should I refinance my student loans to a lower rate?
Refinancing with a private lender can cut your rate and total interest, but it converts federal loans into private ones and permanently forfeits federal protections — income-driven repayment, generous deferment and forbearance, and forgiveness programs. If your income is stable and you won't need those benefits, the savings can be worthwhile; if your income is uncertain or you are pursuing forgiveness, keeping the federal loan is usually safer. Run both rates through this tool to see the interest difference before deciding.