Student Loan Calculator
Calculate student loan monthly payment, total interest, and accrued interest during a grace period.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this student loan calculator
- Enter the total loan amount disbursed (your principal).
- Enter the annual interest rate quoted by your lender or servicer.
- Choose the repayment term in years (10 years is the U.S. standard plan).
- Add a grace period in months if interest accrues before payments begin (typical for unsubsidized loans).
- Press Calculate to see monthly payment, total interest, total cost, and grace-period accrued interest.
About this student loan calculator
A student loan calculator estimates the monthly payment, total interest, and total cost of a student loan, including the effect of a grace period when interest accrues before repayment begins. During a grace period — typically 6 months after graduation in the U.S. — unsubsidized loans continue to accrue simple monthly interest, which is then capitalized (added to the principal) when repayment starts. After capitalization, the amortization formula is M = B × [r(1+r)^n] / [(1+r)^n − 1], where B is the capitalized balance (P + P × r × grace months), r is the monthly rate (APR ÷ 12), and n is the repayment term in months.
For example, a $30,000 unsubsidized loan at 5.5% APR with a 6-month grace period accrues about $30,000 × (0.055/12) × 6 = $825 in grace-period interest, giving a $30,825 starting balance. Amortized over a 10-year (120-month) standard plan, the monthly payment is about $334.62, with total interest near $10,154 and a total repayment around $40,154. The U.S. Department of Education and Federal Student Aid (studentaid.gov) document this capitalization behaviour for unsubsidized federal loans.
This tool is for estimation only and is not financial advice — consult a qualified financial advisor or your loan servicer before deciding on a repayment plan, consolidation, or refinancing.
FAQ
- What is a grace period and why does it matter?
- A grace period is the time between when you leave school and when payments begin (typically 6 months in the U.S.). For subsidized federal loans, the government pays the interest during that time. For unsubsidized loans, interest accrues and is added to your principal — increasing every subsequent payment.
- What is capitalization?
- Capitalization is when unpaid interest is added to the loan principal, so future interest accrues on a larger balance. This tool capitalizes the grace-period interest into a "starting balance" before amortizing.
- Which repayment plan does this calculate?
- This is the U.S. Standard 10-year plan or any custom fixed-term equivalent. It does not model income-driven plans (IDR/SAVE/PAYE), forgiveness, or graduated repayment — those depend on income and family size and change over time.
- Can I make extra payments to reduce interest?
- Yes, federal student loans have no prepayment penalty. Extra payments are typically applied to the principal (you may need to ask the servicer to direct them there) and reduce the total interest you pay.
- Does this work for private student loans too?
- Yes, if your private loan uses fixed-rate monthly amortization, the math is identical. Variable-rate loans require re-calculating when the rate resets — re-run this tool with the new rate.
- Should I use this to choose a repayment plan?
- Use it for estimation only. For income-driven plans, public service loan forgiveness, deferment, or refinancing decisions, talk to your loan servicer or a qualified financial advisor first.