See your monthly payment, total interest, and how much you save by paying extra.
Student loans are unique among forms of debt: they are often taken on by 18-year-olds with no frame of reference for what $50,000 actually means in monthly payments or long-term interest cost. A student loan calculator closes that gap. By entering your loan balance, interest rate, and repayment period, you can see not just your monthly payment but the total amount you will repay — which is often 30–60% more than you borrowed.
For example, a $40,000 federal student loan at 6.53% repaid over 10 years carries a monthly payment of about $453 and a total repayment of $54,360 — meaning you pay $14,360 in interest. Extending that to a 20-year repayment reduces the monthly payment to $301 but increases total interest to $32,240. Knowing these numbers is the first step to making a deliberate repayment decision rather than just accepting the default plan your servicer sets you on.
Student loan interest accrues daily on your outstanding balance. Your annual interest rate is divided by 365 to get a daily rate, and that rate is applied to your principal each day. When your monthly payment arrives, it first covers all accrued interest, then whatever is left reduces your principal. This is why, especially in the early years of repayment, it can feel like your balance barely moves — most of the payment is going to interest.
The standard 10-year repayment plan is the default for federal loans and is the fastest way to pay off under a fixed plan. Income-driven repayment (IDR) plans — SAVE, PAYE, IBR — cap payments at 5–10% of discretionary income and forgive remaining balances after 20–25 years, but you will accrue significantly more interest along the way.
At $394/month (10-year standard plan), you pay $12,280 in interest. Paying just $100 extra per month ($494 total) cuts repayment to 7.5 years and saves $3,640 in interest. Paying $200 extra ($594/month) finishes in just over 6 years, saving $5,500.
For 2024–25, undergraduate Direct Loans are 6.53%, graduate Direct Unsubsidized are 8.08%, and Grad PLUS are 9.08%. Rates are fixed for the life of the loan, regardless of market conditions.
Private lenders offer rates from roughly 4–15% depending on your credit score, income, and the lender. A strong credit score can get you rates below federal loans; a weak score will cost you far more.
Income-driven repayment, Public Service Loan Forgiveness (PSLF), deferment, forbearance, and death/disability discharge are all federal-only benefits. Private loans typically offer none of these.
Refinancing can lower your interest rate, but you permanently give up all federal protections. It only makes sense if your income is stable, you do not plan to pursue PSLF, and the rate reduction is substantial.
For subsidized loans, the government pays the interest while you are enrolled at least half-time. For unsubsidized, interest accrues from day one — and can add thousands to your balance before you make your first payment.
The most powerful lever for reducing your total interest cost is paying more than the minimum. Even small additional payments — $50, $100, $200/month — compound into significant savings over time, because every dollar of extra principal you pay today eliminates future interest that would have accrued on that dollar for the remaining life of the loan.
The bi-weekly payment method is a simple trick that adds one full extra payment per year without requiring a lump sum. Instead of paying your monthly amount once, pay half that amount every two weeks. Since there are 52 weeks in a year, this results in 26 half-payments — equivalent to 13 monthly payments instead of 12. On a $35,000 loan at 6.5%, this alone can shave about 18 months off a 10-year loan.
Windfalls — tax refunds, bonuses, gifts — applied directly to principal have an outsized effect early in the loan when your balance is highest. A $2,000 tax refund applied to principal in year one eliminates that $2,000 from the balance on which interest accrues for the remaining 9+ years.
PSLF forgives remaining federal loan balances after 10 years (120 qualifying monthly payments) while working full-time for a qualifying employer — federal, state, local, or tribal government, or most non-profit organizations. Unlike income-driven forgiveness, PSLF forgiveness is currently tax-free. For borrowers with large balances in public service careers, this can be worth hundreds of thousands of dollars.
To qualify: you must have Direct Loans (not FFEL or Perkins), be enrolled in an income-driven repayment plan or the standard 10-year plan, work full-time for a qualifying employer, and make 120 on-time payments. File an Employment Certification Form annually to track your progress and catch any issues early — not at the end of 10 years.