Free student loan calculator. Find your monthly payment under standard repayment, or project payments and forgiveness under income-driven repayment (IDR).
A student loan calculator shows your monthly payment under standard repayment (a fixed payment that pays off the loan over a set term, like any amortized loan) or under income-driven repayment (a payment set as a percentage of your discretionary income, which can be lower than the interest accruing, with any remaining balance forgiven after 20-25 years).
333,06 €
Monthly payment
Last updated:
Student Loan Calculator
The exact same student loan balance can be repaid two fundamentally different ways. Standard repayment works like any amortized loan — a fixed monthly payment calculated to pay off the full balance, principal and interest, within a set term (commonly 10 years for federal loans). Income-driven repayment (IDR) instead calculates your payment from your income, not your loan balance, which can produce a dramatically different monthly amount and total repayment timeline.
This calculator models both, so you can see the actual monthly payment and total cost difference for your specific balance, rate, and income — not just the general concept.
How IDR Payments Are Calculated
IDR payments are based on "discretionary income" — your annual income above 150% of the federal poverty guideline for your household size, not your total salary. For a single person, if the poverty guideline is around $15,650, 150% of that is roughly $23,475; income above that threshold counts as discretionary. A common IDR formula charges 10% of that discretionary amount per year, divided into monthly payments.
Because the calculation subtracts a protected income floor first, IDR payments scale down significantly for lower earners and can be much smaller than a standard fixed payment — sometimes smaller than the interest accruing on the loan each month.
Forgiveness
Under IDR plans, any remaining loan balance after making qualifying payments for 20 to 25 years (the exact period depends on the specific plan and whether the loans were for undergraduate or graduate study) is forgiven — the remaining debt is cancelled rather than continuing indefinitely.
This makes IDR most valuable for borrowers whose income stays low relative to their loan balance for an extended period, where the forgiven amount at the end can be substantial. For borrowers whose income grows significantly over their career, standard repayment or paying more than the minimum IDR payment often results in less total cost, since less interest accrues over a shorter payoff period.
Limitations
This calculator models a simplified, generic IDR formula (a fixed percentage of income above a poverty-line threshold) rather than any one specific federal program's exact rules, which vary and change over time — actual IDR plans have specific eligibility requirements, may recalculate annually based on updated income and family size, and differ in their exact percentage and forgiveness timeline. It also assumes a constant income growth rate, which real careers rarely follow exactly.
For a general-purpose loan payoff comparison outside the student loan context, see our loan calculator.
Practical Use Cases
Comparing standard vs. income-driven repayment
Seeing the actual monthly payment and total cost difference between the two plans for your specific situation.
Budgeting after graduation
Estimating what your loan payment will actually be once you know your starting salary.
Deciding whether to pay more than the minimum
Testing how extra payments reduce total interest under standard repayment.
Evaluating IDR forgiveness potential
Projecting whether your income trajectory is likely to leave a forgivable balance after 20-25 years.
Planning around a career or income change
Seeing how a lower starting income affects IDR payments compared to a higher one.
Standard repayment sets a fixed monthly payment that pays off the full loan (principal and interest) over a set term, typically 10 years. Income-driven repayment (IDR) instead sets your payment as a percentage of your discretionary income, which can be lower than standard payments — especially early in a career — but may not cover all the accruing interest, and any remaining balance after 20-25 years of payments is forgiven.
Under most IDR plans, discretionary income is your annual income above 150% of the federal poverty guideline for your household size. Only this amount — not your full income — is used to calculate your IDR payment, which is why the payment percentage (commonly 10%) applies to a smaller number than your total salary.
Under current federal tax law (through 2025 under the American Rescue Plan Act, with the treatment for IDR forgiveness specifically extended further), forgiven student loan balances are generally not treated as taxable income at the federal level, though this has changed over time and state tax treatment varies. Check current IRS guidance before relying on this for planning.
If your discretionary income is low relative to your loan balance, your IDR payment can be smaller than the interest accruing each month, meaning your balance grows even while you're making payments (negative amortization). This is expected under IDR — the plan is designed around eventual forgiveness, not necessarily full payoff.
Standard repayment typically results in less total interest paid and full payoff in a shorter, fixed timeframe, but has a higher monthly payment. IDR lowers your monthly payment (helpful if it's a large share of your income) but can mean more total interest over a longer period, with forgiveness only becoming valuable if a balance remains after the forgiveness period. Compare both modes in this calculator against your actual budget.