Student Loan Calculator - Free Monthly Payment and Payoff Estimator (2026)

Federal rates are fixed at first disbursement: 6.53% for undergrad Direct in 2024-25, 7.05% graduate, 8.08% PLUS, with 2025-26 rates set similarly in June. Private rates in 2026 were about 5.5% for 750+ scores, 7% to 9% for 700 scores, and 12%+ for 660. Your weighted average across loans determines the true payment.

Use M = P×[r(1+r)^n]/[(1+r)^n−1] where P is balance, r is monthly rate and n is months. For $35,000 at 6.54% over 120 months, r is 0.00545, (1+r)^n is 1.92, payment is $398, total interest is $12,776. The calculator applies this for every term.

Ten-year costs $398 and $12,776 interest on $35,000 at 6.54%; 20-year costs $262 and $27,826, saving $136 monthly but adding $15,050 in total interest. Choose 10-year if cash flow allows and you want minimum interest, or 20-year/IDR only if cash flow is tight or you pursue PSLF forgiveness after 120 payments.

Most refinance lenders require 680 minimum, with the best 5.5% rates near 750+ in 2026. A 720 score might see 6.5% versus 8% at 660, saving $42 monthly on $50,000 over 10 years ($547 vs $589) and $5,040 total. Check soft-pull pre-qualification before refinancing federal loans.

Enroll in an income-driven plan that caps at 10% to 15% of discretionary income; on $55,000 income the 10% estimate is $458 versus $398 standard — actually higher if income is high. IDR lowers payment only when income is low relative to debt, but adds years and often thousands in interest unless forgiveness applies.

On $35,000 10-year 6.54% at $398 base, $100 extra makes $498 and cuts payoff from 120 to about 89 months, saving 31 months and $3,530 in interest. Adding $200 cuts to 71 months and saves 49 months and $5,646. The earlier the extra starts, the larger the saving.

This calculator does not include: (1) interest capitalization during forbearance or grace when unpaid interest is added to principal; (2) origination fees of 1.057% for Direct and 4.228% for PLUS in 2024-25; or (3) state taxes on forgiven balances, which can be 5% of the forgiven amount.

IDR sets payment at 10% to 15% of discretionary income (income above 150% to 225% of poverty) and recertifies annually. After 20 to 25 years of qualifying payments, any remaining balance is forgiven but may be taxable. At $55,000 income, a 10% IDR estimate is about $458 monthly versus $398 standard on $35,000.

Above 7% loan rate, extra payments are a certain 7% return that beats risky investing; below 5%, investing at the 7% to 10% historical stock return wins. For 6% to 7%, split the difference. Always build a $1,000 starter emergency fund and capture any 401(k) match first, since the match is a 50% to 100% return.

Yes, you can switch federal plans annually, usually with recertification. Extending from 10-year to 20-year on $35,000 at 6.54% drops payment from $398 to $262 but adds $15,050 in interest. Switching back to standard when income rises saves the extra interest, so recalculate before changing.