Estimate your monthly student loan payment and total interest for federal or private loans and any term.
Student loans use the same amortization formula as mortgages and other installment loans. Your monthly payment is calculated so that the loan is paid off in full by the end of the repayment term, with each payment covering both the interest accrued that month and a portion of the principal balance.
The formula: Monthly Payment = P × [r(1+r)^n] / [(1+r)^n - 1], where P is the principal (loan amount), r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12). For example, a $30,000 loan at 5.5% over 10 years results in a monthly payment of approximately $325.61.
Federal vs. private loans: Federal student loans typically offer fixed interest rates set by Congress, income-driven repayment options, and potential loan forgiveness programs. Private student loans may have variable or fixed rates determined by your creditworthiness and usually lack the flexible repayment options of federal loans.
Understanding the payoff schedule: In the early years of repayment, most of your payment goes toward interest rather than principal. As the balance decreases, a larger share goes toward paying down the principal. This is called amortization. Making extra payments toward principal can significantly reduce the total interest you pay over the life of the loan.
Common repayment strategies: The standard 10-year plan has higher monthly payments but minimizes total interest. Extended plans (up to 25 years) lower monthly payments but increase total cost. Income-driven repayment plans cap payments at a percentage of your discretionary income. Consider refinancing if you have good credit and can secure a lower rate.
By paying just $50 extra per month ($375.61), you could pay off the loan 2 years early and save over $2,000 in interest.
Type the total loan amount, either the original principal or your current balance for refinancing scenarios.
Type the APR and the repayment term in years. Federal loans are typically 10-25 years; private loans 5-20 years.
Standard, graduated, or income-driven. Each plan has different monthly payments and total interest. The calculator shows all three side by side.
For related calculations, try our loan calculator.
Cross-checked against authoritative formulas (IRS, NIST, ACM) and updated for 2025/2026 tax years and rates.
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A student loan calculator is a free tool that estimates the monthly payment, total interest, and total cost of federal or private student loans. Our student loan calculator supports standard, graduated, and income-driven repayment plans, plus refinancing comparisons. The student loan calculator also shows loan forgiveness scenarios and the impact of extra payments.
How it works
Our student loan calculator lets you find the monthly payment and total interest for federal or private student loans, in four steps.
Type the current balance of all your student loans combined. If you have multiple loans, sum the balances or run the calculator for each separately.
Type the weighted average APR across your loans. Federal undergraduate loans are typically 4-7%, grad loans 6-9%, private loans 4-12% depending on credit.
Type the repayment period in years. Standard is 10 years for federal loans. Extended and income-driven plans can be 20-25 years.
The result shows your monthly payment, total interest paid, and total amount repaid. Add extra payments to see how much you can save in interest and how much faster you can be debt-free.