College is one of the biggest financial commitments a person makes, and the number that shapes the whole experience is the monthly student loan payment. This student loan calculator estimates what you will owe each month on your federal or private education debt, then adds up the total interest and the full amount you will repay over the life of the loan. Whether you are about to graduate, deciding between a 10-year and 20-year plan, or wondering whether refinancing is worth it, the figures below give you the starting point.
Adjust the sliders and every number updates instantly. You can also add an extra monthly amount to see how much faster you would become debt-free and how many dollars of interest you would cut off.
How to Use
- Enter your Loan Balance — the original amount you borrowed, or the current outstanding balance if you have already been paying for a while. A typical bachelor's degree leaves around $30,000–$40,000 in federal loans.
- Type your Interest Rate (APR). Federal undergraduate rates are fixed for the life of the loan; private student loan rates float with your credit score and whether you have a cosigner. If you do not know your rate, check your most recent statement or your servicer's portal.
- Choose your Repayment Term. The standard federal plan is 10 years, but extended and income-driven plans can stretch payments to 20 or 25 years. A longer term lowers the monthly bill but raises total interest.
- Optionally set an Extra Monthly Payment amount. Even an extra $50 or $100 applied directly to principal shaves years and thousands of dollars off the loan.
The result card breaks out your fixed monthly payment, the total interest paid over the repayment period, the grand total repaid, and — when you add an extra amount — the estimated payoff date.
The Student Loan Payment Formula
Your monthly payment uses the same standard amortization formula applied to every installment loan, including federal Stafford and PLUS loans:
M = P × r(1 + r)ⁿ / ((1 + r)ⁿ − 1)
Where:
- M is the monthly payment.
- P is the loan balance.
- r is the monthly interest rate — the annual APR divided by 12.
- n is the total number of monthly payments — the repayment term in years times 12.
Worked example on a $35,000 loan at 5.50% for 10 years: the monthly rate is 0.004583 and n = 120. Plugging in gives a monthly payment of about $379.84, and over 10 years the total interest paid is roughly $10,581. That means the $35,000 you borrowed actually costs you about $45,581 by the time it is fully repaid. This is why even a small rate difference or a slightly shorter term makes such a large dollar impact.
If the rate is 0% (a rare subsidized promotion or a hypothetical), the formula divides by zero, so the engine simply splits the principal evenly across the number of months: $20,000 over 120 months is $166.67 per month with no interest at all.
10-Year vs 20-Year: Which Repayment Plan Is Better?
Compare two loans on the same $35,000 balance at 5.5%:
- 10-year standard: monthly payment around $380, but total interest only about $10,581.
- 20-year extended: monthly payment drops to roughly $242, but total interest balloons to about $22,000.
The 20-year plan frees up roughly $138 each month on day one, which is a lifeline for a new grad on an entry-level salary — but you pay more than double the interest over time. Choose the longer plan only if the lower payment genuinely fits a tight budget, and step up to a higher payment the moment your income grows. Because federal loans have no prepayment penalty, you can always pay extra on a 20-year plan as if it were a 10-year one, but you cannot stretch a 10-year plan back out.
Federal vs Private Student Loans
Federal loans offer fixed rates, generous deferment and forbearance, and access to income-driven repayment plans that cap your bill at a percentage of discretionary income. Private loans are issued by banks and credit unions, often carry variable rates, and rarely offer those protections. Use this calculator for both — the math is identical — but remember that a private loan's rate can change, so stress-test your budget at a higher rate if it adjusts.
Examples
Example 1 — A typical federal grad. A recent graduate owes $35,000 at a fixed 5.5% rate on the standard 10-year plan. The monthly payment is about $380, and total interest over the decade is roughly $10,581. Setting aside an extra $100 per month toward principal cuts several years off the term and saves several thousand dollars of interest.
Example 2 — Stretching to afford entry-level pay. A borrower with $40,000 at 4.5% switches from a 10-year to a 15-year plan. The monthly payment falls from about $414 to roughly $306, but total interest rises from about $9,700 to $15,080 — a trade-off that buys cash flow in the short term.
Example 3 — A six-figure debt load. A professional-school graduate with $1,000,000 at 6.0% on a 10-year term faces a monthly payment near $11,102 and total interest of roughly $332,246. Running this number before choosing a repayment plan prevents a budget mismatch after graduation.
FAQ
How is a student loan monthly payment calculated?
The payment uses the standard amortization formula M = P × r(1+r)ⁿ / ((1+r)ⁿ − 1), where P is the loan balance, r is the monthly interest rate (annual APR divided by 12), and n is the number of monthly payments (years times 12). This is the same formula used by the U.S. Department of Education's Federal Student Aid servicers and major private lenders.
What is the average student loan payment?
Borrowers with a typical $30,000–$40,000 balance at a federal fixed rate usually pay between $300 and $450 per month on the standard 10-year plan. Payments are lower on extended or income-driven plans and higher on professional-school debt. Use the calculator above with your own balance and rate for a precise figure.
Is a 10-year or 20-year student loan repayment plan better?
A 10-year plan saves tens of thousands of dollars in interest but requires a higher monthly payment. A 20-year plan lowers the bill — helpful when income is low — but roughly doubles total interest. Choose the shortest term you can comfortably afford, and always confirm whether your loan carries a prepayment penalty (federal loans never do).
Are federal student loan interest rates fixed or variable?
Federal student loan interest rates are fixed for the life of the loan and set annually by Congress. Private student loan rates can be either fixed or variable; variable rates start lower but rise and fall with the market, so budget for a worst-case higher rate.
Does paying extra toward student loans save money?
Yes. Even an extra $100 per month on a $35,000 loan at 5.5% can cut years off the term and save thousands of dollars in interest. Make sure your servicer applies the extra amount directly to principal, and confirm there is no prepayment penalty before committing.
Can I use this calculator for private student loans?
Yes. The amortization math is identical for federal and private loans. Just enter your private loan's current APR — remember it may be variable — and balance. Unlike federal loans, private loans generally do not offer income-driven repayment, so plan around the fixed monthly payment this tool produces.
Disclaimer
This student loan calculator is provided for informational purposes only and does not constitute financial, lending, tax, or legal advice. Estimates are based on the inputs you enter and the standard amortization formula; actual offers, interest rates, and repayment terms vary by lender, loan program, credit profile, and year of disbursement. Federal income-driven repayment plans, deferment, forbearance, and forgiveness programs are not modeled here. Always confirm your exact payment and terms directly with your loan servicer or a qualified financial aid professional before making a repayment decision.