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CalculatorBuddy

Student Loan Calculator

Estimate a student loan payment from the remaining term, see how extra payments cut interest, or project the balance through school and the grace period.

Maintained by CalculatorBuddy TeamEditorial methodology

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Enter any three of loan balance, remaining term, interest rate, and monthly payment.

ExampleSample values — edit any field to see your result.

$

Leave blank if unknown — enter any three values.

years

Leave blank if unknown — enter any three values.

%

Leave blank if unknown — enter any three values.

$

Leave blank to compute the standard payment for the term.

Results update as you type.

Repayment

$345.24/month

Estimated result

Total Interest
$11,428.92
Total Payments
$41,428.92

Saved calculations stay only in this browser. Share copies a link containing your entered values.

Principal vs interest

Principal 72%, Interest 28%
  • Principal72%
  • Interest28%

Compare scenarios

Keep a baseline, then change an assumption to see its effect side by side.

Amortization schedule

PeriodInterestPrincipalBalance
Year 1$1,973.21$2,169.69$27,830.31
Year 2$1,820.98$2,321.91$25,508.40
Year 3$1,658.08$2,484.82$23,023.59
Year 4$1,483.74$2,659.15$20,364.44
Year 5$1,297.18$2,845.72$17,518.72
Year 6$1,097.52$3,045.37$14,473.35
Year 7$883.86$3,259.03$11,214.32
Year 8$655.20$3,487.69$7,726.63
Year 9$410.51$3,732.38$3,994.25
Year 10$148.65$3,994.25$0.00
Repayment$345.24 /month

Plan a student loan three ways. The General tab finds the monthly payment (or the missing balance, term, or rate) from any three values. Repayment shows how extra payments or paying the balance in full cut interest versus the current schedule. In school projects the balance through remaining college years and a grace period, then the payment after repayment begins.

Repayment-plan scope

The results are fixed-rate amortization scenarios, not estimates for an income-driven, graduated, extended, consolidation, deferment, forbearance, or forgiveness program. Federal plan availability and rules can change. Use the current tools in your StudentAid.gov account for a federal repayment-plan comparison.

Examples

$30,000 remaining · 10 years · 6.8%

The standard payment is $345.24 a month. You repay $41,428.92 in total, of which $11,428.92 is interest (about 28% of every dollar paid).

Same loan, $350/month plus $150 extra

At $350 a month the remaining term is 9 years and 10 months. Adding $150 extra each month pays it off in 6 years and 2 months — 3 years and 8 months earlier — and saves $4,421.28 of interest.

$20,000 current · $10,000/year for 2 more years · 6-month grace

You will have borrowed $40,000. If interest is not paid in school, the balance is about $44,264 at graduation and $45,790 after the grace period, with a $526.96 monthly repayment and $23,234.95 of total interest.

Formula

Student loans use the same monthly amortization as other installment loans. Monthly rate r is the annual rate ÷ 12.

Known remaining term. The level payment on principal P over n months is:

payment = P × r / (1 − (1 + r)^(−n))

If the monthly payment is known instead, the calculator simulates month by month until the balance clears (the last payment may be partial).

Extra payments. The current monthly payment is kept; extra monthly, yearly (months 12, 24, …), and one-time (month 1) amounts are added on top. Paying the loan back altogether is a lump-sum payoff of the remaining balance today.

While in school. Each remaining school month, unpaid interest is added and new borrowing of (estimated amount per year) ÷ 12 is disbursed:

balance = balance × (1 + r) + annualAmount / 12

The grace period compounds with no new disbursements. Repayment then amortizes that balance over the loan term. If you pay the interest as it accrues, it never capitalizes and repayment is based on the amount borrowed.

Use the pay interest during school choice to model the interest treatment in your own loan documents. This calculator does not determine subsidy eligibility, capitalization events, origination fees, deferment, forgiveness, or income-driven plans.

Frequently asked questions

How is the student loan payment calculated?
With the standard amortizing-loan formula. For a remaining balance P, a monthly rate r (the annual rate divided by 12), and n months, the payment is P × r ÷ (1 − (1 + r)^−n). Each payment covers that month's interest first; the rest reduces principal.
What if I only know three of the four numbers?
The General tab needs any three of loan balance, remaining term, interest rate, and monthly payment. Leave the unknown blank. If you fill in all four, the payment is computed from balance, term, and rate (the entered payment is ignored).
How do extra payments save interest?
Extra amounts go to principal, so they never accrue the interest that principal would have cost. You can add an extra amount every month, once a year at year-end, a one-time extra with the next payment, or any combination. The calculator compares that path with staying on the current monthly payment.
What happens to interest while I am still in school?
Unsubsidized loans accrue interest during school and the grace period. If you do not pay it, this calculator capitalizes it monthly (adds it to the balance) and new borrowing is added as annual amount ÷ 12 each month. Subsidized Direct Loans typically do not accrue interest then — choose Yes for "pay interest during school years" so the repayment principal stays at the amount borrowed.
What is the grace period?
The months between leaving school and required repayment. The period and interest treatment depend on the loan type and status. Enter the period shown in the servicer or lender documents; the calculator then compounds unpaid interest through that user-entered interval.

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