Student Loan Calculator
Estimate student loan monthly payments, grace-period interest, repayment balance, total interest, and total paid. Private client-side tool.
By Utilix Editorial Team · Added May 4, 2026 · Updated Sep 6, 2026
Scenario A
Input
Result
Enter a value for loan balance to see your result.
How it works
Estimates student loan repayment by accounting for interest that accrues during a grace period and the fixed monthly payment after repayment starts.
Formula
Grace Interest = P × (r / 12) × grace months Repayment Balance = P + Grace Interest (if capitalized) Monthly Payment = P_adj × r / (1 − (1 + r)^(−n))
- P
- Original loan balance
- P_adj
- Balance at start of repayment (after capitalization)
- r
- Monthly interest rate (annual rate ÷ 12 ÷ 100)
- n
- Total monthly payments (repayment years × 12)
Step by step
- 01Calculate simple interest accrued during the grace period.
- 02Optionally add that interest to the repayment balance.
- 03Convert the annual rate to a monthly rate.
- 04Apply the amortized loan formula across the repayment term.
Examples
$40,000 at 5.5% with 6-month grace
Six months of interest adds about $1,100 before repayment if it capitalizes.
Inputs
- Loan balance:
- 40000
- Annual interest rate:
- 5.5
- Repayment term:
- 10
- Grace period:
- 6
- Grace interest:
- 1
Result
- Monthly payment:
- 449.84
- Balance at repayment:
- 41100
More about this tool
Student loans differ from most consumer loans because a grace period — typically 6 months after graduation — delays your first payment while interest may keep accruing. This calculator models that gap explicitly:
Grace Interest = P × (annual rate / 12) × grace months
Repayment Balance = P + Grace Interest (if capitalized)
Monthly Payment = Repayment Balance × r / (1 − (1 + r)^(−n))
Capitalization: The Hidden Cost
If your loan is unsubsidized, interest accrues from disbursement — including during school and any grace period. Whether that accrued interest gets added to ("capitalized onto") your principal balance before repayment starts makes a real difference: capitalized interest then earns interest itself for the rest of the loan term. Toggle the "Grace interest" option to compare both scenarios side by side.
Subsidized vs Unsubsidized Loans
Federal subsidized loans (need-based, undergraduate only in the US) don't accrue interest while you're in school or during the grace period — the government covers it. Unsubsidized loans accrue interest the entire time, whether or not you're required to make payments. This calculator's grace-period interest calculation applies to unsubsidized balances; set grace months to 0 if your loan is fully subsidized through that period.
What This Calculator Doesn't Model
Income-driven repayment plans (which base payments on income rather than a fixed amortization schedule), deferment and forbearance, and loan forgiveness programs all change the effective cost of federal student loans in ways a fixed-payment calculator can't capture. Use this tool for standard fixed repayment estimates, and check your loan servicer's income-driven repayment estimator if you're considering that path.
Compare a standard 10-year term against extended repayment options using the comparison toggle to see the total interest trade-off before choosing a plan.
Frequently asked questions
What does capitalization mean?
Capitalization adds unpaid interest to principal, so future interest is charged on a larger balance.
Does this model income-driven repayment?
No. It models fixed amortized repayment, not income-driven plans, subsidies, or forgiveness.
Should I make payments during the grace period?
If you can afford it, paying even just the interest during the grace period prevents it from capitalizing onto your principal, which lowers your total interest over the life of the loan. Check whether your loan is subsidized (interest may not accrue during grace) or unsubsidized (interest accrues regardless).
Is a longer repayment term ever a good idea?
It can be, if it frees up cash flow for other financial priorities (emergency fund, employer 401k match, higher-interest debt) — but you'll pay more total interest. Compare a standard 10-year term against extended options here before choosing.
How does refinancing a student loan affect this calculation?
Refinancing replaces your current balance and rate with a new loan, typically from a private lender. It can lower your rate if your credit has improved, but refinancing federal loans into a private loan forfeits federal protections like income-driven repayment and forgiveness programs — model the new terms here, but weigh that trade-off first.