Student Loan Calculator
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About Student Loan Repayment
Student debt's defining choice is payment-versus-total: the standard 10-year plan hurts monthly but minimizes interest; stretched terms breathe easier and cost thousands more. Seeing both numbers before picking — or before refinancing — is the whole game.
Enter your balance, rate, and candidate term for the payment, total repaid, and interest as a percent of principal. Run it at 10 and 20 years and the trade-off prices itself. Multiple loans? Run each — their rates differ, and that difference drives payoff order.
The same amortization engine, general-purpose, lives in the Loan Calculator
The Standard-Plan Math
Fixed-payment amortization, the same formula behind mortgages:
Payment = P × r ÷ (1 − (1 + r)⁻ⁿ) r = rate ÷ 1200 · n = months
Worked example: $30,000 at 5.5% on the standard 10-year plan → $325.58/month, repaying $39,069 total ($9,069 interest — 30% of principal). The same loan at 20 years: $206/month but $19,532 of interest — the payment relief costs $10,463.
Term Length vs Total Cost
$30,000 at 5.5% across the standard term menu (all computed by this calculator):
| Term | Monthly | Total interest | Interest vs principal |
|---|---|---|---|
| 10 years | $325.58 | $9,069 | 30% |
| 15 years | $245.11 | $14,120 | 47% |
| 20 years | $206.39 | $19,533 | 65% |
| 25 years | $184.23 | $25,268 | 84% |
The last column is the honest price tag of low payments: at 25 years, interest nearly equals the degree itself.
Levers That Shrink the Total
Extra payments attack principal directly — $50/month extra on the worked example's 10-year plan finishes ~19 months early and saves ~$1,600 (tell your servicer to apply extras to principal, not to advance the due date). Order matters with multiple loans: highest rate first, always, while paying minimums on the rest.
Refinancing trades federal protections for rate: private refis can cut interest meaningfully for strong credit, but federal loans surrender IDR eligibility, potential forgiveness programs, and hardship deferments the moment they're refinanced — irreversibly. The sequence that respects both: exhaust federal-specific advantages first, refinance only what doesn't need them, and never refinance federal loans while any forgiveness path realistically applies to you.
Frequently Asked Questions
What's the monthly payment on $30,000 of student loans?
$325.58 at 5.5% on the standard 10-year plan; about $206 stretched to 20 years — at the cost of $10,000+ extra interest. Enter your actual rate above; federal and private rates vary widely by year and credit.
What is the standard repayment plan?
Federal loans default to fixed payments over 10 years — the plan this calculator models. It minimizes total interest among the standard menu; income-driven alternatives lower payments by computing from income instead, usually extending the timeline.
Should I pay off student loans early?
The math: extra payments earn your loan's rate risk-free — compelling at 7%+, debatable below employer-match returns (capture the 401k match first). The exception: loans on a realistic forgiveness track, where prepaying can literally waste money.
How does income-driven repayment differ?
IDR plans set payments as a share of discretionary income — the balance and rate stop driving the monthly number, and remaining debt can be forgiven after 20–25 years. The official studentaid.gov simulator handles those; this calculator covers the standard and private-loan math.
Is refinancing my student loans worth it?
For private loans: usually yes when your credit has improved. For federal loans: only after honestly pricing what you surrender — IDR, forgiveness eligibility, and hardship options don't survive the refi. The rate cut is visible; the safety net you'd burn isn't, until you need it.
How do I pay off multiple loans efficiently?
Avalanche: minimums on everything, every spare dollar at the highest rate. Run each loan here to see its numbers; a 6.8% grad loan beats a 3.7% undergrad loan for extra dollars every time, whatever the balances suggest emotionally.
Methodology. This calculator uses standard financial formulas used across the industry. It is reviewed and maintained by the Vast Calculators editorial team.
Last updated · July 11, 2026
Disclaimer. This tool provides estimates for general informational purposes only and is not a substitute for professional financial advice. Always consult a qualified financial advisor before making decisions about your finances.