Student loan debt is the second-largest consumer debt category in the United States, and the number that determines whether it feels manageable or crushing is the monthly payment. This student loan payment calculator estimates what you owe each month under the standard 10-year repayment plan, then lets you switch to an income-driven repayment (IDR) plan to see how a payment tied to your discretionary income compares. Adjust the sliders and every figure updates instantly, including the total interest you will pay over the life of the loan.
Whether you are a recent graduate trying to budget your first paycheck, a borrower deciding between federal and private consolidation, or a parent wondering whether refinancing actually saves money, starting from an accurate monthly number keeps the rest of the conversation honest.
How to Use
- Enter your Student Loan Balance — the total outstanding principal. If you have several loans, add them together for a blended estimate.
- Type your Interest Rate (APR). Federal student loans have fixed rates set by Congress; private loans vary with your credit. If you hold a mix, enter the weighted average.
- Choose your Loan Term. The standard federal plan is 10 years, but extended and graduated plans stretch to 20 or 25 years.
- Set the Repayment Plan to Standard to amortize principal and interest, or switch to IDR to model an income-driven plan.
- If you choose IDR, enter your Annual Gross Income and the IDR Share of Income (most plans cap payments at 10% of discretionary income).
- Read the result card: your Monthly Payment, the Total Interest Over Life, the Total Repaid, and the Estimated Payoff Time.
The standard plan uses the same amortization formula the U.S. Department of Education and every major servicer relies on. The IDR plan uses a simplified discretionary-income model so you can compare a payment tied to your salary against a fixed amortizing payment.
The Student Loan Payment Formula
Your monthly principal-and-interest payment comes from the standard amortization formula:
M = P × r(1 + r)ⁿ / ((1 + r)ⁿ − 1)
Where:
- M is the monthly payment.
- P is the outstanding loan balance.
- r is the monthly interest rate — the annual APR divided by 12.
- n is the total number of monthly payments — the loan term in years times 12.
Worked example on a $35,000 balance at 5.5% for the standard 10-year plan: the monthly rate is 0.004583, n = 120, and the formula produces a monthly payment of $379.84. Over 10 years you repay about $45,581 in total, of which roughly $10,581 is interest. That is the baseline most graduates should compare every other plan against.
If the interest rate is 0%, the formula divides by zero, so the engine simply splits the principal evenly across the number of months: $20,000 over 120 months is $166.67 per month with zero interest.
Standard vs. Income-Driven Repayment
The standard plan gives you a fixed payment that clears the loan in 10 years, but it can be a stretch on an entry-level salary. Income-driven repayment plans (PAYE, REPAYE/SAVE, IBR, and ICR) instead cap your bill at a percentage of discretionary income — commonly 10% — and forgive any remaining balance after 20 or 25 years.
On a $50,000 annual income, an IDR plan set to 10% of discretionary income works out to about $417 per month ($5,000 per year divided by 12). That may be lower than the standard payment, but it often means the balance grows during the early years because the payment does not cover accruing interest — a phenomenon called negative amortization. IDR can be the right safety net when cash flow is tight, but it is not automatically cheaper.
Examples
Example 1 — The standard 10-year baseline. A graduate owes $35,000 at 5.5% and stays on the standard plan. The monthly payment is $379.84, total interest is about $10,581, and the loan is gone in 120 months. This is the number to beat.
Example 2 — Switching to IDR. The same borrower earns $50,000 and enrolls in a 10%-of-discretionary-income plan. The payment drops to roughly $417 per month — actually close to the standard bill here — but because the payment is income-linked it will rise as salary grows, and any balance left after 20–25 years may be forgiven (taxed as income).
Example 3 — The long-term reach. On a $1,000,000 balance at 6.0% stretched over 20 years, the monthly payment is about $7,164, and the total interest over the life of the loan exceeds $719,000. Running this number before you commit to graduate school prevents you from borrowing more than your expected income can realistically service.
FAQ
How is a student loan monthly payment calculated?
The standard payment uses the amortization formula M = P × r(1+r)ⁿ / ((1+r)ⁿ − 1), where P is the loan balance, r is the monthly interest rate (APR divided by 12), and n is the number of monthly payments (years times 12). This is the same formula used by the Federal Student Aid office and major servicers.
What is the average student loan payment?
Federal data puts the typical monthly payment around $300–$400 for recent graduates, but it depends heavily on your balance, interest rate, and plan. A $35,000 loan at 5.5% over 10 years is about $380 per month; stretching the term to 20 years lowers the payment but increases total interest.
Should I choose a standard or an income-driven repayment plan?
Choose the standard plan if your salary comfortably covers the fixed payment and you want to finish in 10 years while paying the least interest. Choose an income-driven plan (SAVE, PAYE, IBR, ICR) if your cash flow is tight, you expect to qualify for Public Service Loan Forgiveness, or you need a payment that rises with your income.
How does IDR calculate my monthly payment?
Income-driven plans set your bill at a percentage of your discretionary income — usually 10% — rather than amortizing the balance. On $50,000 of income, a 10% share is about $417 per month. Payments recertify annually with your income and family size, and remaining balances may be forgiven after 20–25 years.
Does extending my student loan term lower my payment?
Yes. Stretching a loan from 10 to 20 years reduces the monthly payment because the principal is spread across more months, but you pay far more total interest. Use this calculator to enter longer terms and compare the monthly relief against the extra interest cost.
Are interest rates on student loans fixed or variable?
Federal student loans issued after 2006 have fixed rates set annually by Congress, so your payment never changes over the life of the loan. Most private loans offer either fixed or variable rates; variable rates start lower but can rise, increasing your monthly payment over time.
Disclaimer
This student loan payment calculator is provided for informational purposes only and does not constitute financial, lending, tax, or legal advice. Estimates use the standard amortization formula and a simplified income-driven repayment model; actual amounts depend on your servicer, loan type, federal plan rules, family size, and poverty-line adjustments that are not fully modeled here. Interest, forgiveness, and tax figures are approximations. Confirm your exact payment and plan options with your loan servicer or a qualified financial professional before making a repayment decision.