Student Loan Calculator
Calculate your monthly student loan payment, total interest, and the impact of a grace period before repayment begins.
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How to use this calculator
M = monthly payment, P = balance after grace period (including accrued interest), r = monthly rate, n = total repayment months.
- 1
Enter the total amount borrowed for your education.
- 2
Enter the annual interest rate on your student loan.
- 3
Enter the repayment term in years (standard is 10 years for federal loans).
- 4
Enter any grace period — the months after graduation before payments are required.
Frequently asked questions
How does the tool treat the grace period?
It assumes the full balance keeps accruing interest during the grace period, compounded monthly and added to the balance when repayment starts: balance = loan × (1 + r)^months, with r the annual rate ÷ 12. No payments are made during the grace period. Whether interest really accrues, and how it is capitalised, depends on the type of loan and the lender’s terms.
What formula sets the monthly payment?
This tool uses payment = B × r ÷ (1 − (1 + r)^−n), where B is the balance after the grace period, r is the annual rate ÷ 12 and n is the repayment term in years × 12. Payments are level and made at the end of each month. With the defaults, B is $30,834.51 and the payment is $334.64.
How much does the grace period add?
On $30,000 at 5.5% over 10 years, no grace period gives $325.58 a month and $9,069.46 of interest. Six months gives $334.64 and $10,156.26, and twelve months gives $343.94 and $11,273.28. The “Total Interest Paid” line includes the interest that built up during the grace months.
Is the repayment term in years and the grace period in months?
Yes. Enter the repayment term in years and the grace period in whole or fractional months. A repayment term of 0 returns n/a because there is no payment to compute.
What happens at 0%?
At exactly 0% no interest accrues during the grace period either, so the balance stays at the original amount and the payment is the loan divided by the months: $250.00 for $30,000 over 10 years, with $0.00 total interest.
Does it model income-driven plans, forgiveness or deferment?
No. The payment is a fixed amount calculated from the formula. Income-based payments, rate discounts, subsidies, forgiveness, forbearance and later capitalisation events are not modelled, and nor is paying interest during the grace period.
Are fees or several loans included?
No. Origination fees, servicing charges and late fees are not part of the maths, and the tool handles a single loan with one rate. For several loans, run each separately and add the payments yourself.
Could my servicer’s figure differ?
Yes. Servicers may use daily simple interest, round each payment, or capitalise differently from the monthly compounding here. The rate, rules and terms in your loan agreement govern, and real rates change.
Student loan repayment: the effect of a grace period and a repayment term
Interest first, then repayment
The calculator works in two stages. During the grace period, no payments are made but the balance grows by (1 + r) each month, where r is the annual rate divided by 12. Repayment then starts on the grown balance, and a level payment is computed over the term. The defaults ($30,000 at 5.5%, 6 months of grace, 10 years of repayment) produce a balance of $30,834.51 after grace, which includes $834.51 of grace interest.
Worked example: how the grace period raises the payment
With the default loan, grace of 0, 6 and 12 months gives payments of $325.58, $334.64 and $343.94, and total interest of $9,069.46, $10,156.26 and $11,273.28. A larger loan makes the effect clearer: $45,000 at 6.8% with 9 months of grace and a 15-year term grows to $47,347.71, so the payment is $420.30 and total interest is $30,653.65, of which $2,347.71 accrued before the first payment. The payment rises with the grace months because the same repayment term has to clear a larger starting balance.
Choosing a repayment term on the default loan
Leave the $30,000 loan, 5.5% rate and 6-month grace period alone and change only the repayment years. Shorter terms raise the payment but leave far less interest; the grace-period interest of $834.51 is the same in every row, since the grace months come before the term and do not depend on it. Each total in the last column is the grace interest plus the repayment interest beside it.
| Repayment term | Monthly payment | Interest during repayment | Total interest paid |
|---|---|---|---|
| 5 years | $588.97 | $4,503.99 | $5,338.50 |
| 10 years | $334.64 | $9,321.75 | $10,156.26 |
| 20 years | $212.11 | $20,071.09 | $20,905.61 |
Zero rate and invalid terms
At a 0% rate the grace period adds nothing, the balance stays at the loan amount and $30,000 over 10 years is $250.00 a month. A loan amount or repayment term of 0 produces n/a rather than a misleading number.
Where real loans differ
Servicers may accrue interest daily, apply subsidies, offer income-linked plans, forgiveness or deferment, and capitalise at different moments. None of that is modelled here. Real rates, fees and rules change, so the loan agreement and servicer statement are what govern the repayment amount.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →