Student Loan Calculator
Project repayment timelines and interest on student loans.
Estimates only, not financial, tax, or legal advice. See our Terms and Privacy Policy.
Student loans come in two very different flavors. Federal loans carry fixed rates set by Congress each year and include borrower protections like income-driven repayment and forgiveness programs. Private loans are credit-based and priced like any other consumer loan, with fewer safety nets.
Before you commit, check how this payment affects your debt-to-income ratio.
This calculator amortizes a student loan on the standard fixed schedule, useful for both federal standard repayment and private loans, showing your monthly payment, total interest, and how extra payments shorten the payoff.
How does this calculator work?
Enter the loan balance, term, and interest rate. The federal standard repayment plan uses a 10-year term; private loans and refinances vary, so use your actual term.
The calculator computes a fixed monthly payment and a full amortization schedule. Solve for any field by entering a target payment to see what term fits.
Add an extra monthly payment to retire the debt faster. There are no prepayment penalties on student loans, so every extra dollar goes to principal and saves interest.
Worked example
Consider a $35,000 student loan balance at 6.5% APR on the standard 10-year plan.
- Loan balance
- $35,000
- Term / APR
- 10 yrs / 6.5%
- Monthly payment
- $397.42
- Total interest
- $12,690
- With $100 extra/month
- paid off 2 yrs 7 mos early
How the numbers work
The $397.42 payment is the amortization result for $35,000 at 6.5% (about 0.542% per month) over 120 months.
The first month's interest is $35,000 × 0.542% = $189.58, so only $207.83 reduces principal at the start. Paying an extra $100 a month ($497.42 total) sends that whole $100 straight to principal every month, and the effect compounds.
That extra payment clears the loan in 89 months instead of 120, dropping total interest from $12,690 to $9,186.
On the standard plan you'd pay $12,690 in interest over ten years. Adding $100 a month retires the loan 31 months, two years and seven months, early and saves $3,504 in interest.
Student loan interest may be deductible up to $2,500 a year as an above-the-line deduction, subject to income limits, a benefit that can lower the effective cost of the debt.
Federal vs. private, and the refinancing trade-off
Federal loans offer protections private loans don't: income-driven repayment plans that cap payments as a share of income, deferment and forbearance options, and potential forgiveness through programs like Public Service Loan Forgiveness. Federal rates are fixed when you borrow and the same for everyone in a given year.
Refinancing into a private loan can lower your rate, but it permanently forfeits those federal protections. That trade-off only makes sense if you have strong, stable income and won't need income-driven repayment or forgiveness. Run the payment both ways before deciding, and never refinance federal loans you might want to forgive.
Subsidized, unsubsidized, and the grace period
Subsidized federal loans don't accrue interest while you're in school or during the grace period; the government covers it. Unsubsidized and private loans accrue interest from disbursement, and any unpaid interest is typically capitalized (added to principal) when repayment begins, which raises the balance this calculator amortizes. Most loans include a six-month grace period after graduation before payments start.
Student Loan Calculator glossary
- Federal Loan
- A government student loan with a fixed annual rate and borrower protections like income-driven repayment.
- Private Loan
- A credit-based student loan from a bank or lender, priced individually and without federal protections.
- Subsidized Loan
- A federal loan on which the government pays the interest while you're in school and during the grace period.
- Capitalization
- Unpaid accrued interest being added to the principal balance, increasing the amount you owe.
- Income-Driven Repayment
- A federal plan that caps your payment as a percentage of discretionary income.
- Grace Period
- A window (usually six months) after leaving school before student loan payments begin.
- Deferment / Forbearance
- Temporary pauses on payments for hardship or school; interest may still accrue, especially in forbearance.
- Loan Servicer
- The company that manages your loan and collects payments, and who you contact to change plans or apply extra payments.
- Refinancing
- Replacing existing loans with a new private loan at a lower rate; refinancing federal loans forfeits their protections.
Student Loan Calculator FAQs
What's a typical student loan interest rate?+
Federal student loan rates are set annually by Congress (recently around 5%–8%) and are fixed for the life of the loan. Private loan rates vary with your credit and can be fixed or variable.
Should I refinance my federal student loans?+
Only with caution. Refinancing into a private loan can lower your rate but permanently gives up federal protections like income-driven repayment and forgiveness. It generally suits borrowers with strong, stable income who won't need those programs.
Is student loan interest tax deductible?+
You may deduct up to $2,500 of student loan interest per year as an above-the-line deduction, subject to income phase-outs. It's available even if you don't itemize. Confirm eligibility for your situation.
Do extra payments help on student loans?+
Yes. Student loans have no prepayment penalty, so extra payments go entirely to principal, shortening the loan and cutting interest. The calculator shows the time and money saved.