Quick answer
A student loan calculator projects the payment and lifetime interest on education debt. Borrow $37,000 at 5.5% and the standard 10-year plan costs $401.55 a month and $11,186 of interest. Every point of rate and every year of term moves the interest total by thousands — the calculator lets you test repayment plans before you commit to one, by term or by the monthly payment you can afford.
How the Student Loan Calculator works, step by step
Enter the total balance (add up every loan if you have several — or run the calculator per loan, since each carries its own rate), the interest rate and the repayment term. For multiple loans use a balance-weighted average rate for a quick estimate. The tool also works backwards: enter the monthly payment you can afford and it tells you how long payoff takes.
Interest starts accruing on federal unsubsidised and PLUS loans from the day the money is disbursed, including while you are in school. Interest that accrues before repayment capitalises — it is added to the principal — so a loan taken out in the first year of a four-year degree can enter repayment owing materially more than was borrowed at typical rates.
Compare plans by total interest and by payment together. Stretching the term from 10 to 20 years on the example loan cuts the payment from $401.55 to $254.52 but raises total interest from $11,186 to $24,084. The calculator's standard-versus-extended table makes that trade visible for your own balance, and the chart shows how slowly the extended balance falls.
Federal rates are fixed for each loan at disbursement and reset annually by formula (the 10-year Treasury yield plus a margin). For loans first disbursed between July 1, 2026 and June 30, 2027, the rates are 6.52% for undergraduate Direct Loans, 8.07% for graduate unsubsidised loans and 9.07% for Direct PLUS loans. At 6.52% the example's 10-year payment would be $420.50 with $13,461 of interest.
The repayment landscape changed in 2026. The SAVE plan ended, the new Repayment Assistance Plan (RAP) launched on July 1, 2026 — payments of 1% to 10% of adjusted gross income, a $10 minimum, forgiveness after 30 years — and loans disbursed on or after that date can use only RAP or the new Tiered Standard Plan. Income-Based Repayment stays open for older loans; PAYE and ICR close by July 1, 2028. Confirm your options at studentaid.gov.
The formula
Monthly payment = Balance × [r(1 + r)^n] ÷ [(1 + r)^n − 1], r = annual rate ÷ 12, n = months in the plan. Total interest = (payment × n) − balance. In payment mode the calculator simulates month by month — interest = balance × r, the rest of the payment reduces principal — until the balance reaches zero.
Worked example — try it on the calculator above
Worked example: $37,000 at 5.5% on the standard plan
Payment: $401.55 a month for 120 months. Total repaid: $48,186, of which interest is $11,186 — you repay about $1.30 for every $1 borrowed. If $6,000 of interest had capitalised during school (a realistic figure for four years of unsubsidised borrowing), the starting balance is really $43,000 and the same plan costs $466.66 a month with about $13,000 of further interest. Paying a flat $400 a month instead of the exact plan payment stretches payoff to 121 months with $11,248 of interest — a $1.55 shortfall costs a month and $62.
Frequently Asked Questions
What are the current federal student loan rates?
Rates are fixed for each loan at disbursement and reset annually by formula (10-year Treasury yield plus a margin). For loans first disbursed July 1, 2026 to June 30, 2027: 6.52% for undergraduate Direct Loans, 8.07% for graduate unsubsidised loans and 9.07% for Direct PLUS loans, with a 1.057% loan fee on Direct Loans. Private student loans price on creditworthiness and range from around 4% to the mid-teens.
What happens during the grace period?
Federal loans typically give six months after leaving school before payments start. Interest on unsubsidised loans keeps accruing through the grace period and capitalises when repayment begins. Paying the interest as it accrues — about $170 a month on a $37,000 balance at 5.5% — prevents capitalisation and keeps the repayment balance equal to what you actually borrowed for tuition.
Should I refinance federal student loans privately?
Only with a clear-eyed trade. A private refinance at a lower rate can save real money, but it permanently surrenders federal protections: income-driven repayment, deferment and forbearance rights, and any eligibility for forgiveness programmes including Public Service Loan Forgiveness. For borrowers with high, stable private-sector incomes and no forgiveness path, the rate saving may be worth it; for everyone else it usually is not.
How much student debt is reasonable?
A common rule: total borrowing no more than your expected first-year salary in the field you are entering. On a $55,000 starting salary, a $55,000 balance at 6.52% takes about $625 a month for 10 years — about 14% of gross pay, before rent. Debt well above first-year salary is where standard repayment starts to break household budgets.
Estimates, not advice. This calculator provides educational estimates based on the inputs you enter and the assumptions shown on this page. It is not financial, tax or investment advice, and it cannot see your full situation. Verify important figures against official sources, and consider a qualified professional for decisions about your own money. See our Disclaimer and Methodology.