Student Loan Payment Calculator
Enter your loan balance, interest rate, and repayment term to get your monthly payment, total interest, and full payoff date. Switch to the extra-payment tab to see exactly how much time and interest you save by paying a little more each month. An amortization schedule shows the balance, interest, and principal for every payment.
How student loan payments are calculated
Student loan payments are calculated using the standard amortization (PMT) formula: each payment covers that month's accrued interest and a portion of the principal, so the balance falls to zero at the end of the term. The formula is PMT = P x [r(1+r)^n] / [(1+r)^n - 1], where P is the starting balance, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments. For a $30,000 loan at 5.5% over 10 years (120 months), the monthly rate is 0.4583%, and the required payment works out to about $325 per month.
Interest capitalisation during grace periods
Most federal student loans include a 6-month grace period after graduation. Interest accrues during that period, and if it is not paid down, it capitalises: that is, it gets added to the principal. A $30,000 unsubsidised loan at 5.5% accumulates about $825 in grace-period interest before repayment even begins, raising the effective starting balance and increasing every future payment by a small amount. Subsidised Stafford loans are an exception: the federal government pays the interest during the grace period, so your balance stays flat. If you can afford to make interest-only payments during the grace period, it is one of the highest-return moves available to new graduates.
How extra payments reduce your total cost
Because interest is calculated on the remaining balance, every dollar of extra principal payment immediately reduces future interest charges. If your standard payment is $325 and you pay $425 instead, the $100 extra goes entirely toward principal. That shrinks the balance faster, so less interest accrues in subsequent months, and the cycle compounds in your favour. On a $30,000 loan at 5.5%, adding $100 per month cuts the payoff time by roughly 2.5 years and saves more than $2,500 in interest. The savings grow non-linearly: the earlier in the loan life you make extra payments, the more you save.
Federal repayment plans and income-driven options
The standard 10-year plan minimises total interest but can feel unaffordable for new graduates on modest salaries. Income-driven plans (IBR, PAYE, REPAYE, ICR) cap payments at a percentage of your discretionary income, typically 10-15%, and forgive any remaining balance after 20-25 years. The tradeoff is that lower payments mean more time for interest to accrue, so you often end up paying more in total. Public Service Loan Forgiveness (PSLF) is the exception: after 10 years of qualifying payments while working for a government or non-profit employer, the remaining balance is forgiven tax-free. This calculator uses the standard amortization formula (fixed-payment plans). For income-driven projections, your servicer's website or the Federal Student Aid Loan Simulator are the authoritative tools.
Federal Student Loan Repayment Plans
| Plan | Term | Payment Type | Loan Forgiveness |
|---|---|---|---|
| Standard | 10 years | Fixed | None |
| Graduated | 10 years | Increases every 2 years | None |
| Extended | Up to 25 years | Fixed or graduated | At end of term (taxable) |
| Income-Based (IBR) | 20-25 years | 10-15% of discretionary income | Yes (taxable) |
| Pay As You Earn (PAYE) | 20 years | 10% of discretionary income | Yes (taxable) |
| Revised PAYE (REPAYE) | 20-25 years | 10% of discretionary income | Yes (taxable) |
| Income-Contingent (ICR) | 25 years | 20% of discretionary income or 12-yr fixed | Yes (taxable) |
| Public Service (PSLF) | 10 years | Qualifying payments | Yes (tax-free after 120 payments) |
Reference guide to federal repayment options. Eligibility and terms depend on loan type and financial situation.
Frequently asked questions
What is the standard student loan repayment term?
Federal student loans default to a 10-year standard repayment plan. Private loans vary by lender, with terms typically ranging from 5 to 20 years. Choosing a longer term lowers your monthly payment but increases the total interest you pay. The calculator lets you adjust the term to see the exact trade-off.
How does the grace period affect my loan balance?
Most federal loans give you a 6-month grace period after leaving school. Unsubsidised loans continue to accrue interest during that time. If you do not pay the interest as it accrues, it capitalises (gets added to your principal). This makes every subsequent payment slightly larger because you are now paying interest on a bigger balance. Subsidised loans are exempt: the government covers that grace-period interest for you.
Is it worth paying extra on my student loans?
Usually yes, especially early in the loan. Because interest is charged on the outstanding balance, paying extra principal today saves disproportionately more interest tomorrow. The savings are most powerful in the first few years when the balance is highest. One consideration: if you expect to qualify for income-driven forgiveness or PSLF, extra payments on loans headed for forgiveness may not be the optimal move. But for borrowers on the standard plan, extra payments nearly always come out ahead.
What is the difference between subsidised and unsubsidised loans?
The federal government pays the interest on subsidised loans while you are enrolled at least half-time, during the grace period, and during authorised deferment. On unsubsidised loans you are responsible for all interest from disbursement day one. If you let it accrue and capitalise, your starting repayment balance will be larger than the amount you originally borrowed.
Can I pay off my student loans early without a penalty?
Yes. Federal student loans have no prepayment penalty, and most private lenders follow the same policy (though it is worth checking your promissory note). You can make extra payments at any time, and all of the overage goes directly to principal as long as you tell your servicer to apply it that way rather than advancing your next due date.
How does the income-driven repayment (IDR) payment compare to the standard plan?
Income-driven plans set your payment at 10-20% of your discretionary income (your income minus 150% of the federal poverty guideline for your family size). For a single borrower earning $40,000 per year, the PAYE payment might be around $110-180 per month, far below the roughly $325 standard payment on a $30,000 loan. The catch is that stretching repayment to 20-25 years means far more interest accrues, so your total cost is higher unless your remaining balance is forgiven at the end of the plan.