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Student Loan Repayment Calculator

Income-driven repayment cuts your payment in half but can nearly double your total interest. On a $35,000 loan at 5.5%, standard repayment costs $10,560 in interest. IDR costs $18,400. That $7,840 difference is the price of lower monthly payments. Adding just $100/month extra to the standard plan saves $2,800 and gets you out 2 years early. This calculator lays every scenario side by side so you pick the plan that actually fits your goals.

By SplitGenius TeamUpdated February 2026

A $35,000 student loan at 5.5% interest on a standard 10-year plan costs $380/month and $10,582 in total interest. Adding just $100/month in extra payments cuts your payoff to 7 years and saves $3,100 in interest. Enter your loan balance, interest rate, repayment plan, and any extra payment below to see your exact monthly payment, total interest cost, and how much faster you can be debt-free.

Loan Details

$

Total remaining balance across all loans

%

Federal undergrad rate is ~5.5% for 2024–25

Repayment Plan

Fixed monthly payments over 10 years. Lowest total interest cost.

Extra Monthly Payment(optional)

$

Extra payments go directly to principal. Federal loans have no prepayment penalty.

How This Calculator Works

1

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2

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Federal Student Loan Repayment Plans Compared

Federal student loans offer four main repayment plans. Your choice determines your monthly payment, total interest, and how long you carry the debt. Here's how they stack up on a $35,000 loan at 5.5% interest:

PlanMonthly PaymentTermTotal InterestTotal Paid
Standard$38010 years$10,582$45,582
Graduated$228 → $456+10 years$12,400+$47,400+
Extended$21525 years$29,400+$64,400+
Income-Driven (SAVE/IBR)10% discretionary20 – 25 yearsVaries widelyForgiveness possible

Standard repayment costs the least in total interest because you pay it off fastest. Extended repayment cuts your monthly payment by 43% but nearly triples your interest cost. The graduated plan starts low and increases every two years—it costs more than standard but less than extended. Income-driven plans cap payments at a percentage of your discretionary income and forgive any remaining balance after 20–25 years, which can be a lifeline if your income is low relative to your debt.

Why Extra Payments Matter More Than You Think

Student loan interest compounds monthly. Every dollar you pay above the minimum goes straight to principal, which means next month's interest is calculated on a smaller balance. The savings compound over years.

On a $35,000 loan at 5.5% with standard 10-year repayment:

Extra PaymentMonthly TotalPayoff TimeInterest SavedTime Saved
$0 (minimum)$38010 years
+$50/month$4308 yr 6 mo$1,70018 months
+$100/month$4807 yr 4 mo$3,10032 months
+$200/month$5805 yr 10 mo$4,90050 months

An extra $100/month saves $3,100 in interest and eliminates nearly 3 years of payments. You don't need to double your payment—even $50/month makes a meaningful dent. Federal student loans have no prepayment penalty, so every extra dollar counts immediately.

One critical detail: when you make extra payments, tell your servicer to apply them to principal only. Some servicers default to advancing your due date instead, which doesn't reduce your interest cost at all.

Should You Pay Off Student Loans Early or Invest?

This depends on one number: your loan's interest rate versus your expected investment return after taxes.

Pay off early when: Your rate exceeds 6–7%. Private loans at 8%+ should be attacked aggressively—no diversified portfolio reliably beats that after taxes. If you're not getting employer 401(k) matching, pay the loans first.

Invest instead when: Your federal loans are at 3–5% and you're on an income-driven plan heading toward forgiveness. The math clearly favors minimum payments plus investing the difference in a broad market index fund. But this only works if you actually invest—not spend—the savings.

The hybrid approach: Max your employer match first (that's a guaranteed 100% return), then split remaining cash between extra loan payments and a Roth IRA. This works especially well for loans in the 5–6% gray zone where the math is roughly a wash either way.

Don't forget the student loan interest deduction: you can deduct up to $2,500 in student loan interest per year if your modified adjusted gross income is under $90,000 (single) or $185,000 (married filing jointly). That effectively lowers your real interest rate by your marginal tax bracket.

If you're juggling credit card debt alongside student loans, use our credit card payoff calculator to see where to focus first—high-rate credit cards almost always beat student loan prepayment. For a strategy to tackle multiple debts at once, try the debt snowball calculator. And for general loan math on auto loans or personal loans, the loan payment calculator shows the full amortization breakdown.