Student loan calculator
Free student loan calculator. See your monthly payment, total interest, and exactly how much extra payments cut off the payoff date.
Typical student loan numbers
The average US borrower graduates with ~$37,000 in student loans. At 6.5% on a standard 10-year plan, that's $420/month for 120 payments with about $13,400 in total interest.
Federal vs private student loans
Federal (Direct Loans)
- Fixed rates set annually by Congress
- Income-driven repayment plans (SAVE, PAYE, IBR)
- Public Service Loan Forgiveness after 10 years (PSLF)
- Deferment and forbearance options
- Death/disability discharge
- Generally do NOT refinance these unless you're sure you won't need the protections
Private
- Variable or fixed rates, credit-based
- No forgiveness, no income-driven plans
- Limited hardship options
- Freely refinance for better rates as credit improves
Extra payment impact
On $35,000 at 6.5% over 10 years:
- $0 extra: $420/mo, $13,400 interest, 10 years
- $100/mo extra: $7,580 interest saved, payoff 2.3 years early
- $200/mo extra: $9,900 interest saved, payoff 3.8 years early
- $500/mo extra: $12,000 interest saved, payoff 6 years early
If your loan has an "excess payment" instruction field, always specify "apply to principal". Otherwise servicers may advance the due date instead of reducing principal — wasting your extra payment.
Should you pay off aggressively?
Compare your rate to your alternative use of money:
- Rate under 5% (old federal loans): pay minimum, invest extra in index funds (~7% real)
- Rate 5-7% (current federal): split — some extra payments, some investing
- Rate 7%+ (grad school, private): aggressive payoff usually wins
Always capture employer 401(k) match first — that's a free 100% return, beats any loan rate.
Income-driven repayment: when it makes sense
Federal IDR plans cap payments at 5-10% of discretionary income, with loan forgiveness after 20-25 years (or 10 years for public service). Math:
- Worth it: low income relative to balance (e.g., $100k loans on a $50k teacher salary heading toward PSLF)
- Bad idea: high income, low balance — you'll pay more in interest over 20 years than you would under standard repayment