Student Loan Repayment Calculator

Student loan interest is calculated using simple daily interest, not compound interest like a credit card. Your daily interest charge equals your outstanding principal balance multiplied by your interest rate, divided by 365.25. This means interest accrues every day on your remaining balance.

The interest calculation formula:

• Daily interest = Outstanding principal × (Annual interest rate / 365.25)
• Monthly interest ≈ Daily interest × days in the billing period (roughly 30)
• Payment allocation = Interest accrued first, then remaining payment goes to principal

Why this matters: In the early years of repayment, a large portion of each payment goes toward interest rather than reducing your principal. On a $35,000 loan at 6.53%, your first monthly payment of about $398 allocates roughly $190 to interest and only $208 to principal. Over time, as the balance shrinks, more of each payment goes to principal.

This is why extra payments are so powerful — every extra dollar goes directly to principal reduction, which lowers the daily interest accrual going forward. Even $50 extra per month can save thousands in total interest and shave years off your repayment timeline. The earlier you make extra payments, the more you save because you prevent interest from compounding on a larger balance.

Subsidized vs. unsubsidized also matters for interest. On subsidized loans, the government pays interest while you're in school and during deferment periods. On unsubsidized loans, interest accrues from the day the loan is disbursed — meaning your balance can grow significantly before you even start repaying.

Income-driven repayment (IDR) plans cap your monthly student loan payment at a percentage of your discretionary income — the difference between your adjusted gross income (AGI) and 150-225% of the federal poverty guideline for your family size. After 20-25 years of qualifying payments, any remaining balance is forgiven.

Current IDR plan options:

• SAVE Plan — 10% of discretionary income (5% for undergraduate-only loans). Forgiveness after 20 years for undergrad loans, 25 years for graduate. Discretionary income calculated using 225% of the poverty line (most generous threshold).
• PAYE — 10% of discretionary income, capped at the Standard plan payment amount. Forgiveness after 20 years. Must demonstrate “partial financial hardship.”
• IBR (Income-Based Repayment) — 10-15% of discretionary income depending on when you borrowed. Forgiveness after 20-25 years. Available to most federal borrowers.
• ICR (Income-Contingent Repayment) — 20% of discretionary income or a fixed 12-year payment adjusted for income, whichever is less. Forgiveness after 25 years. The only IDR plan available for Parent PLUS loans (via consolidation).

The forgiveness trade-off: IDR plans result in lower monthly payments but significantly more total interest over the repayment period. In many cases, you may pay more in total than you originally borrowed. However, for borrowers with high debt and modest income (especially graduate school debt), the forgiveness amount can be substantial — sometimes exceeding six figures.

Tax implications: Under current law, IDR forgiveness is tax-free through 2025 under the American Rescue Plan Act. After 2025, forgiven amounts may be treated as taxable income, creating a potentially large “tax bomb.” Public Service Loan Forgiveness (PSLF) forgiveness is always tax-free, regardless of this provision.

Extra payments on student loans create a guaranteed, risk-free return equal to your interest rate. On a 6.53% loan, every extra dollar you pay is equivalent to earning 6.53% on an investment — tax-free, with zero risk. This makes paying extra on student loans one of the most reliable financial moves available.

The math on extra payments:

• $100/month extra on a $35,000 loan at 6.53% saves approximately $4,800 in interest and pays off the loan about 3 years early.
• $200/month extra saves approximately $7,200 in interest and pays off roughly 4.5 years early.
• $500/month extra saves approximately $10,000+ in interest and cuts the payoff timeline nearly in half.

Best strategies for extra payments:

• Target the highest-rate loan first — If you have multiple loans, direct extra payments to the one with the highest interest rate (the avalanche method). This minimizes total interest paid.
• Specify that extra payments go to principal — Contact your servicer to ensure extra payments reduce principal, not advance your due date. Some servicers will apply extra payments to future payments by default, which doesn't reduce interest accrual.
• Use windfalls strategically — Tax refunds, bonuses, and side income make excellent lump-sum payments. A single $3,000 tax refund applied to principal can save hundreds in interest over the remaining loan term.
• Automate biweekly payments — Paying half your monthly amount every two weeks results in 26 half-payments (13 full payments) per year instead of 12. That extra payment each year accelerates payoff significantly.

Use this calculator's extra payment simulator to see the exact impact for your loan balance and rate. Small, consistent extra payments often produce surprisingly large savings.

Federal student loan interest rates are set annually by Congress and are based on the 10-year Treasury note yield from the May auction, plus a fixed margin. Once set, the rate is fixed for the life of the loan — it won't change even if market rates move later.

2025-2026 federal student loan rates:

• Direct Subsidized Loans (Undergraduate) — 6.53% fixed. Available to undergrads who demonstrate financial need. The government pays interest while you're in school at least half-time.
• Direct Unsubsidized Loans (Undergraduate) — 6.53% fixed. Available to all undergrads regardless of financial need. Interest accrues from disbursement.
• Direct Unsubsidized Loans (Graduate/Professional) — 8.08% fixed. Available to graduate and professional students.
• Direct PLUS Loans (Grad PLUS & Parent PLUS) — 9.08% fixed. Available to graduate students and parents of dependent undergrads. Requires a credit check.

How these rates compare historically: The current 6.53% undergraduate rate is above the historical average. Rates hit a low of 2.75% for loans disbursed in 2020-2021. If you have older loans at lower rates, prioritize paying off any newer, higher-rate loans first.

Private student loans are different — they can have fixed or variable rates set by the lender based on your credit score, often ranging from 4% to 16%+. Variable-rate private loans carry additional risk because payments can increase if market rates rise. Refinancing federal loans into private loans may lower your rate but you lose access to IDR plans, forgiveness programs, and federal protections.

Refinancing student loans means replacing one or more existing loans with a new private loan, ideally at a lower interest rate. This decision involves significant trade-offs that depend on your financial stability, career plans, and how much you value federal loan protections.

When refinancing makes sense:

• You have strong credit and stable income — If your credit score is 720+ and you have a stable job, you may qualify for rates significantly below your current federal rate. A 2-3 percentage point reduction on a large balance saves thousands.
• You won't need IDR or forgiveness — If your income is high enough that you'll never benefit from income-driven repayment or forgiveness, the federal protections have less value to you.
• You have PLUS loans at 9.08% — Grad PLUS and Parent PLUS loans carry the highest federal rates. Refinancing these specifically can yield substantial savings while keeping other federal loans on IDR plans.

When you should NOT refinance:

• You work in public service — PSLF forgives remaining federal loan balance after 10 years of qualifying payments. Refinancing into a private loan permanently disqualifies those loans from PSLF.
• Your income is uncertain — Federal loans offer deferment, forbearance, and IDR plans if you lose your job or income drops. Private lenders generally offer far less flexibility during hardship.
• You're close to forgiveness — If you've been making IDR payments for 15+ years, refinancing would restart the clock and eliminate the forgiveness you've been working toward.

A hybrid approach often works best: refinance high-rate private or PLUS loans where savings are clear, while keeping subsidized federal loans on their current plan. Never refinance a loan you might want forgiven.

The student loan interest deduction allows you to deduct up to $2,500 per year in student loan interest paid from your taxable income. This is an “above the line” deduction, meaning you don't need to itemize — you can claim it even if you take the standard deduction.

Eligibility requirements:

• Income limits (2025) — The deduction phases out for single filers with modified AGI between $80,000 and $95,000, and for married filing jointly between $165,000 and $195,000. Above these thresholds, no deduction is available.
• Qualifying loans — Both federal and private student loans qualify, as long as the loan was taken out solely to pay qualified education expenses. Loans from family members or employer plans do not qualify.
• Filing status — You cannot claim the deduction if you file as married filing separately. You also cannot be claimed as a dependent on someone else's return.

How much does it actually save? The deduction reduces your taxable income, not your tax bill directly. If you're in the 22% tax bracket and deduct the full $2,500, you save $550 in federal taxes. If you're in the 24% bracket, the savings is $600. Your servicer will send you a Form 1098-E showing the interest paid during the year.

Strategic note: Because this deduction has income phase-out limits, high earners gradually lose the benefit. If you're near the phase-out range, strategies like maximizing pre-tax retirement contributions (401(k), HSA) can reduce your AGI below the threshold and preserve the full deduction.

Missing student loan payments can have serious consequences — late fees, credit score damage, and eventually default. But there are several options available before you miss a payment that can provide relief without long-term financial damage.

Federal loan options when you can't pay:

• Switch to an IDR plan — Income-driven plans can reduce your payment to as low as $0/month if your income is below 150-225% of the poverty line. Payments of $0 still count toward forgiveness timelines. This is the first option to explore.
• Deferment — Temporarily pause payments (up to 3 years) for qualifying reasons: returning to school, unemployment, economic hardship, or active military service. On subsidized loans, interest doesn't accrue during deferment. On unsubsidized loans, it does.
• Forbearance — Temporarily pause or reduce payments (up to 12 months at a time, up to 3 years total). Easier to qualify for than deferment, but interest accrues on all loan types and capitalizes (gets added to principal) when forbearance ends.
• Recertify your IDR income — If you're already on an IDR plan and your income has dropped, recertify early to get a lower payment immediately rather than waiting for the annual recertification date.

What happens if you default: Federal loans enter default after 270 days of missed payments. Consequences include wage garnishment (up to 15% of disposable pay), tax refund seizure, Social Security offset, damaged credit, and loss of eligibility for future federal aid. Default is recoverable through loan rehabilitation (9 on-time payments over 10 months) or consolidation, but it's far better to use deferment, forbearance, or IDR before reaching that point.

Private loan options are more limited. Contact your lender directly to ask about hardship programs, temporary payment reductions, or interest-only payment periods. Private lenders are not required to offer these but many do to avoid the cost of collections.