Student Loan Calculator
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Calculate student loan monthly payments, total interest, and payoff timeline. Compare different repayment terms.
Monthly Payment
$0
📊 Compare repayment terms
📐 Formula
Monthly Payment = P × [r(1+r)^n] / [(1+r)^n − 1]. Standard term: n=120 months (10 years)
How to Use the Student Loan Calculator
Enter your total balance
Input the combined balance of all loans. Federal and private loans can be entered together if similar rates, or separately for precision.
Enter the interest rate
Use your current rate. Federal Direct undergraduate loans are fixed at the rate set when you borrowed. Private loans may have variable rates that reset annually.
Set the repayment term
Standard federal repayment is 10 years (120 months). Extended plans allow 20–25 years. Income-driven plans tie payments to income rather than balance.
Try extra payment scenarios
Even $50/month extra on a $35,000 loan at 6.5% saves over $4,000 in interest and cuts more than a year off the repayment period.
Federal vs Private Student Loans: Critical Differences
Federal student loans offer borrower protections unavailable on private loans: income-driven repayment (IDR), deferment, forbearance, and potential forgiveness including Public Service Loan Forgiveness (PSLF — full forgiveness after 10 years of qualifying public sector employment). Federal Direct Subsidised loans do not accrue interest while enrolled at least half-time. Unsubsidised loans accrue from disbursement — if unpaid during school, this interest capitalises onto the principal, increasing the amount borrowed before repayment even begins.
Income-Driven Repayment: Who Benefits Most
Federal IDR plans (SAVE, PAYE, IBR) cap monthly payments at 5–20% of discretionary income and forgive balances after 10–25 years of qualifying payments. IDR is most valuable for borrowers with high debt relative to income — particularly those in public service careers where PSLF provides forgiveness after just 10 years. For high-income earners who can afford standard payments, the extended IDR timeline often results in higher total interest paid than standard 10-year repayment. Compare total lifetime cost across plans before selecting — the monthly payment difference can be misleading about overall cost.
Refinancing: When It Makes Sense (and When It Doesn't)
Refinancing federal loans into a private loan permanently eliminates federal protections — IDR eligibility, PSLF qualification, deferment rights. For borrowers in public service or with high debt-to-income ratios, this is rarely advisable. For private loan holders or those with stable high incomes and no interest in federal forgiveness programmes, refinancing to a lower rate can save significant money. A $40,000 private loan refinanced from 8.5% to 5.5% saves approximately $7,200 in interest over 10 years — substantial for those who qualify for prime rates.
Making the Most of Your Grace Period
Most federal student loans provide a 6-month grace period after graduation before repayment begins. Rather than ignoring this window, use it strategically: make interest-only payments during the grace period to prevent capitalisation on unsubsidised loans, research and enrol in your chosen repayment plan before the first payment is due, and build one month of emergency fund before starting full repayments. Starting repayment 30 days prepared is significantly better than starting 30 days behind.
How to Calculate Student Loan Payments by Hand: Worked Example
Take a $30,000 federal loan at 6.53% over the standard 10-year term. Using M = P × [r(1+r)ⁿ] ÷ [(1+r)ⁿ − 1] with monthly rate 0.0653 ÷ 12 = 0.005442 and n = 120: M = $341.10 per month, with total interest of 120 × $341.10 − $30,000 = $10,932.24 over the life of the loan.
What does capitalized interest during school and grace actually cost?
Unsubsidized federal loans accrue interest from disbursement, even while you're enrolled. On the same $30,000 principal at 6.53% over a typical 4.5-year school-plus-grace period, simple interest accrues to roughly $8,815.50. When that accrued interest capitalizes (gets added to principal at repayment start), your 10-year repayment is then calculated on approximately $38,815 rather than $30,000 — permanently raising both the monthly payment and the total interest paid, which is why many advisors recommend paying at least the accruing interest during school if at all possible.
Federal vs Private Student Loans: What Actually Differs?
What protections do federal loans have that private loans don't?
Federal loans offer income-driven repayment plans, deferment and forbearance options, and eligibility for forgiveness programs tied to qualifying employment. Private loans are underwritten like conventional consumer credit — fixed contractual terms with far less flexibility if income drops, though sometimes at a lower rate for well-qualified, creditworthy borrowers.
Who benefits most from income-driven repayment?
Borrowers whose federal loan payment under the standard 10-year plan would exceed roughly 10–15% of discretionary income. Income-driven plans cap the payment as a percentage of income (commonly 10%) and extend the term to 20–25 years, at the cost of more total interest paid over the longer timeline — a trade of monthly affordability now for total cost later.
When does refinancing student loans make sense?
Refinancing to a private lender can lower the rate for borrowers with strong income and credit, but it permanently forfeits federal protections (income-driven plans, forgiveness eligibility, deferment). It rarely makes sense for anyone still relying on those safety nets, and is worth considering mainly for borrowers with stable, sufficient income who are confident they won't need federal flexibility again.
Frequently Asked Questions
For 2024–25: Direct Subsidized/Unsubsidized (undergraduate) 6.53%, Unsubsidized (graduate) 8.08%, Direct PLUS 9.08%. Rates are set annually by Congress based on the 10-year Treasury note.
The standard federal repayment plan is 10 years (120 payments). It results in the least interest paid. Extended plans (20–25 years) lower monthly payments but dramatically increase total interest.
Several programs exist: Public Service Loan Forgiveness (PSLF) after 10 years working for qualifying employers, Income-Driven Repayment (IDR) forgiveness after 20–25 years, and various profession-specific programs. Check studentaid.gov for current status.
Sources & Methodology
Calculations are based on the most current publicly available data from authoritative government and industry sources: