Student Loan Calculator
Estimate student loan monthly payments, grace-period interest, repayment balance, total interest, and total paid. Private client-side tool.
Added May 4, 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
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.