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Student Loan Calculator

Estimate student loan monthly payments and total interest over the repayment term.

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Monthly payment
$318.2
Total interest
$8,183.59
Total paid
$38,183.59

How it works

This calculator estimates the fixed monthly payment on a student loan repaid on a standard, level schedule. Enter the loan balance at the start of repayment, the annual interest rate, and the term in years, and it returns the monthly payment together with the total interest and the total amount you will repay over the full term.

The math is the standard amortization formula: payment = P × r × (1 + r)ⁿ / ((1 + r)ⁿ − 1), where P is the balance, r is the monthly rate (annual rate ÷ 12 ÷ 100), and n is the number of monthly payments (years × 12). Each payment is the same size, but its makeup shifts: early on, much of it covers interest on the large balance, and over time an increasing share retires principal. Results are rounded to the cent.

A fully worked example: repay $30,000 at 5% over 10 years — the standard federal term. The monthly rate is 0.05 ÷ 12 ≈ 0.004167 and n = 120, so (1.004167)¹²⁰ ≈ 1.6470. The payment is 30,000 × 0.004167 × 1.6470 ÷ (1.6470 − 1) ≈ $318.20 per month. Over 120 payments that totals $38,183.59, of which $8,183.59 is interest. Stretch the same balance to 20 years and the payment falls by $120.21 to $197.99, but total interest climbs to $17,516.81 — $9,333.22 more for the lower payment.

A few caveats when reading the results. Enter the balance at repayment start, not the amount you borrowed: unsubsidized loans accrue interest during school and grace, and unpaid interest may capitalize into the balance. The tool models a fixed-rate, fixed-term schedule only — income-driven repayment, deferment, forbearance, and forgiveness programs follow different rules, and variable-rate private loans will drift from the estimate when the rate changes. If you hold several loans at different rates, calculate each one separately and add the payments rather than averaging the rates.

Frequently asked questions

How is the monthly payment calculated?
It uses the standard amortizing-loan formula payment = P × r × (1 + r)ⁿ / ((1 + r)ⁿ − 1), where r is the monthly rate and n the number of months. This matches a level (fixed) repayment plan, where every payment is the same and the interest share shrinks as the balance falls.
What balance should I enter?
Use the balance at the moment repayment begins, not the amount you originally borrowed. Unsubsidized loans accrue interest while you are in school and during grace, and unpaid interest may capitalize — get the current payoff balance from your servicer for the most accurate result.
I have several loans at different rates — how do I model them?
Run the calculator once per loan and add the monthly payments; that is exact. Entering the combined balance at a rough average rate only approximates the total, because each loan’s interest depends on its own rate and balance.
Does this model deferment, forbearance, or income-driven plans?
No — it assumes a standard fixed payment for the whole term. Income-driven plans set payments from your income and family size instead, and interest that accrues during deferment or forbearance can increase the balance you eventually repay. Use this tool for standard or private fixed-rate repayment.
Should I pick a 10-year or a 20-year term?
On $30,000 at 5%, the 10-year payment is $318.20 with $8,183.59 in total interest; over 20 years the payment drops by $120.21 to $197.99, but total interest more than doubles to $17,516.81 — $9,333.22 extra. A longer term buys monthly breathing room at a steep lifetime cost.
Do extra payments help?
Yes — anything above the required payment reduces principal, and every future month’s interest is charged on that smaller balance. Ask your servicer to apply extra amounts to principal (and to the highest-rate loan first) rather than advancing your due date.
Is my data uploaded?
No — the calculation runs entirely in your browser and nothing you enter leaves your device.

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