Student Loan Calculator
Calculate your monthly student loan payment, total interest, and full amortization schedule — for either a federal or a private loan.
Calculator verified • Last updated: August 2026
Federal student loan rates are set annually by law and are the same for all borrowers with the same loan type, regardless of credit history.
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Amortization Schedule
| Period | Payment | Principal | Interest | Balance |
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Balance Over Time
Standard repayment splits each fixed payment between interest and principal, and interest takes the bigger share while the balance is still large — so the balance barely moves at first, then falls faster as more of each payment goes toward what you actually borrowed.
How to Calculate a Student Loan Payment
A student loan, whether federal or private, is repaid with the same fixed-rate amortization formula used for auto loans and mortgages:
M: the monthly payment.
P: the loan amount (principal borrowed).
r: the monthly interest rate (the annual rate divided by 12).
n: the number of monthly payments (repayment term in years × 12).
Federal vs. Private Student Loans
Federal student loan interest rates are set annually by the U.S. Department of Education, fixed by law, and identical for every borrower with the same loan type — a first-year undergraduate taking out a federal Direct Loan pays the same rate as any other first-year undergraduate that year, regardless of credit history or income. Private student loans work more like any other consumer loan: individual lenders set their own rates based on the borrower's (or cosigner's) credit score, income, and the lender's own underwriting — two students borrowing the same amount for the same school can end up with noticeably different private-loan rates. This is a large part of why private loans often carry higher rates than federal loans for borrowers without an established credit history, and why financial aid guidance usually recommends exhausting federal loan options first.
Why Repayment Term Length Matters
A longer repayment term lowers the monthly payment by spreading the same principal over more payments, but it also means interest keeps accruing on a slower-shrinking balance for longer, which raises the total interest paid over the life of the loan. Standard federal repayment is typically 10 years, though extended and income-driven plans can stretch repayment considerably longer in exchange for a lower monthly payment.
Juggling Multiple Loans: Consolidation vs. Refinancing
Borrowers leaving school with several separate loans usually have two very different tools available, and it's easy to confuse them. A federal Direct Consolidation Loan bundles multiple federal loans into a single new one with one monthly payment, at a fixed rate that's simply the weighted average of the old rates, rounded up to the nearest eighth of a percent — it simplifies billing and can make you eligible for certain repayment or forgiveness plans your original loans weren't, but it rarely lowers your rate and can reset progress toward income-driven forgiveness. Refinancing, usually done through a private lender, replaces one or more loans with a brand-new private loan and can secure a meaningfully lower rate for borrowers with strong credit and income — but it permanently converts any federal loans involved into a private one, giving up federal protections like income-driven repayment, deferment, and Public Service Loan Forgiveness in the process. The right choice depends on whether keeping federal protections matters more to you than a lower rate.
Worked Example
A 30,000-dollar federal student loan at 5.5% over the standard 10-year term: the monthly rate is 5.5% ÷ 12 ≈ 0.4583%, and n = 120 payments. Plugging into the formula gives a monthly payment of about 326 dollars, with roughly 9,069 dollars in total interest paid over the 10 years — for a total repayment of about 39,069 dollars on the original 30,000-dollar loan.
Student Loan Terms You Should Know
Principal — the original amount borrowed, before any interest is added.
Income-Driven Repayment (IDR) — a federal repayment option that sets the monthly payment as a percentage of discretionary income rather than a fixed amortized amount. The main calculator assumes a standard fixed payment; use the "Estimate Income-Driven Payment" toggle above for a rough, simplified approximation of what an IDR plan might charge instead.
Grace Period — a window after leaving school (commonly six months for federal loans) before regular repayment is required to begin.
Subsidized vs. Unsubsidized — on a subsidized federal loan, the government covers interest while you're in school and during grace periods/deferment; on an unsubsidized loan, interest accrues the whole time and capitalizes (gets added to principal) once repayment starts if left unpaid.
Capitalization — when accrued, unpaid interest is added to the loan's principal balance, so future interest is then charged on the larger total. Common at the end of a grace period or deferment on an unsubsidized loan; the Grace Period / Deferment field above estimates this.
Origination Fee — a one-time fee deducted from your disbursement before you receive it. Federal loans set this by law (currently about 1.057%-4.228% depending on loan type); private lenders vary. Enter it above to see your real "Amount You'll Actually Receive" — your monthly payment stays the same either way, since it's still calculated on the full loan amount, not the reduced proceeds.
This calculator provides estimates for informational purposes only and is not a loan offer, a guarantee of any specific rate or terms, or financial advice. Actual student loan terms depend on your lender, loan program, and (for private loans) your creditworthiness — confirm exact figures with your loan servicer.
Frequently Asked Questions
What's the difference between federal and private student loans?
Federal student loan rates are set annually by law and are the same for every borrower with the same loan type, regardless of credit history. Private student loan rates are set by individual lenders and vary based on the borrower's (or cosigner's) credit score, so two borrowers with the same loan amount can get very different rates.
How is a student loan payment calculated?
Standard fixed-rate amortization: M = P × r(1+r)^n / [(1+r)^n − 1], where P is the loan balance, r is the monthly interest rate, and n is the number of monthly payments over the repayment term.
Would an income-driven repayment plan give me a lower payment?
The main calculator models standard fixed-payment repayment, but checking "Estimate Income-Driven Payment" and entering your income and family size gives a rough estimate of what a plan like PAYE, REPAYE, or SAVE might charge — roughly 10% of your income above 150% of the federal poverty line for your family size, divided by 12. This is a simplified approximation, not an exact eligibility or payment calculation from your loan servicer, but it shows whether an income-driven plan is even in the right ballpark for your situation.
Does an origination fee change my monthly payment?
No. An origination fee is deducted from your loan proceeds at disbursement, not from your monthly payment — you still owe and pay interest on the full loan amount. The fee only reduces how much you actually receive, which this calculator shows as "Amount You'll Actually Receive."
Should I consolidate or refinance multiple student loans?
They're different tools. Federal Direct Consolidation combines several federal loans into one with a single payment, at a fixed rate that's the weighted average of your old rates rounded up slightly — it simplifies billing but rarely lowers your rate, and it can restart the clock on income-driven or forgiveness progress. Refinancing (usually through a private lender) can get you a meaningfully lower rate if your credit and income are strong, but it converts federal loans into a private one, permanently forfeiting federal protections like income-driven repayment, deferment, and loan forgiveness programs — a real trade-off worth weighing carefully, not just a rate comparison.
What's the difference between a subsidized and unsubsidized student loan?
On a subsidized federal loan, the government pays the interest while you're in school at least half-time and during your grace period or deferment, so your balance doesn't grow during those times. On an unsubsidized loan, interest accrues the whole time, including while you're in school, and if unpaid it's capitalized (added to your principal) once repayment starts — which is exactly what the Grace Period / Deferment field above estimates.