Student Loan Calculator
Student Loan Calculator is a tool that computes your monthly payment, total interest, and payoff date for federal or private student loans. It supports standard fixed repayment and income-driven repayment (IDR) plan estimates, and shows potential loan forgiveness amounts under PSLF and other programs. Enter your loan balance, interest rate, and repayment term to see results instantly.
How Student Loan Payments Are Calculated
Student loan monthly payments use the standard amortization formula:
Where P is the loan balance, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12).
Step-by-step example
A $35,000 undergraduate loan at 5.50% over 10 years:
- P = 35,000
- r = 0.055 ÷ 12 = 0.004583
- n = 10 × 12 = 120 payments
- (1 + r)n = (1.004583)120 = 1.7289
- Numerator: 35,000 × 0.004583 × 1.7289 = 277.33
- Denominator: 1.7289 − 1 = 0.7289
- M = 277.33 ÷ 0.7289 = $380.35/month
Over 120 payments: total paid = $45,642, total interest = $10,642.
How interest accrues
Student loan interest is calculated daily on most federal loans. The daily interest charge is:
- Daily Interest = Outstanding Balance × (Annual Rate ÷ 365.25)
On a $35,000 balance at 5.50%, daily interest is $5.27. That's about $160 per month going to interest alone at the start of repayment. Over time, as you pay down the balance, more of each payment goes toward principal.
Worked Examples
Average undergraduate borrower
Loan: $35,000 at 5.50%, 10-year standard
Monthly: $380
Total interest: $10,642 (30% of principal)
Graduate school debt
Loan: $80,000 at 7.05%, 10-year standard
Monthly: $931
Total interest: $31,724 (40% of principal)
Extended repayment (20 years)
Loan: $35,000 at 5.50%, 20-year extended
Monthly: $242
Total interest: $23,006 (66% of principal)
Effect of extra payments
$35,000 at 5.50%, 10 years + $100/month extra
Payoff: 7.4 years instead of 10
Interest saved: $3,090
How Interest Rate Changes Total Cost
On a $35,000 loan over 10 years:
| Rate | Monthly Payment | Total Interest | Total Paid |
|---|---|---|---|
| 4.00% | $354 | $7,511 | $42,511 |
| 5.50% | $380 | $10,642 | $45,642 |
| 7.05% | $408 | $13,924 | $48,924 |
| 8.05% | $425 | $16,039 | $51,039 |
| 10.00% | $463 | $20,513 | $55,513 |
The jump from 5.50% to 10.00% nearly doubles total interest — from $10,642 to $20,513 — while the monthly payment increases by only $83.
Understanding Student Loan Repayment Plans
Federal Student Loan Rates (2024-25)
| Loan Type | Interest Rate | Borrower |
|---|---|---|
| Direct Subsidized/Unsubsidized | 5.50% | Undergraduate |
| Direct Unsubsidized | 7.05% | Graduate/Professional |
| Direct PLUS | 8.05% | Parents/Graduate |
| Private Loans | 4–14% (varies) | Any |
Standard vs. Income-Driven Repayment
Standard Repayment uses fixed monthly payments over 10 years. You pay less total interest but have higher monthly payments. This is the default plan for federal loans.
Income-Driven Repayment (IDR) caps payments at a percentage of discretionary income and extends the term to 20–25 years. Monthly payments are lower, but total interest is higher. Any remaining balance may be forgiven after the repayment period.
IDR Plan Comparison
| Plan | Payment Cap | Forgiveness | Key Detail |
|---|---|---|---|
| SAVE | 5% (undergrad) / 10% (grad) | 20–25 years | Replaces REPAYE; uses 225% of poverty line |
| PAYE | 10% of discretionary income | 20 years | Must be a new borrower after Oct 2007 |
| IBR | 10–15% of income | 20–25 years | 15% for borrowers before July 2014 |
| ICR | 20% or 12-year fixed | 25 years | Whichever payment amount is lower |
Practical Tips for Student Loan Repayment
- Autopay discount: Most federal servicers reduce your rate by 0.25% when you enroll in autopay.
- Extra payments go to principal: Paying more than the minimum reduces your balance faster and saves interest. Specify that extra payments should apply to principal, not future payments.
- Refinancing trade-offs: Refinancing private loans at a lower rate can save money. Refinancing federal loans into a private loan means losing access to IDR plans, PSLF, and deferment/forbearance protections.
- Employer repayment programs: Some employers offer student loan repayment assistance as a benefit — check your benefits package.
- Tax deduction: You may deduct up to $2,500 of student loan interest per year on your federal tax return, subject to income limits.
Common Mistakes
- Ignoring interest during grace period. Unsubsidized loans and PLUS loans accrue interest during school and the 6-month grace period after graduation. On a $35,000 unsubsidized loan at 5.50%, roughly $4,800 in interest can capitalize by the time repayment starts after a 4-year degree.
- Comparing monthly payments instead of total cost. Extended and IDR plans lower monthly payments but dramatically increase total interest. A $35,000 loan costs $10,642 in interest over 10 years vs. $23,006 over 20 years — the "savings" of $138/month costs an extra $12,364 in interest.
- Refinancing federal loans without considering protections. A lower rate looks appealing, but you permanently lose access to income-driven plans, PSLF, and hardship options like deferment and forbearance.
- Making minimum payments without a strategy. If you have multiple loans, targeting the highest-rate loan first (avalanche method) saves the most interest. Targeting the smallest balance first (snowball method) provides faster psychological wins.
- Forgetting that IDR forgiveness may be taxable. Under current law, balances forgiven through IDR plans after 20–25 years may be treated as taxable income. PSLF forgiveness, however, is tax-free.
- Not recertifying income for IDR plans. IDR plans require annual income recertification. Missing the deadline can cause your payment to revert to the standard plan amount, which may be significantly higher.
Student Loan Calculator FAQ
How do I calculate my student loan monthly payment?
Use the formula M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the loan balance, r is the monthly interest rate (annual rate ÷ 12), and n is total payments (years × 12). Or enter your numbers above and get the result instantly.
How much total interest will I pay on my student loans?
It depends on your balance, rate, and repayment term. On a $35,000 loan at 5.50% with standard 10-year repayment, you'll pay about $10,642 in interest — roughly 30% of the original loan. Extending to 20 years more than doubles the interest to $23,006.
What is the difference between subsidized and unsubsidized loans?
Subsidized loans don't accrue interest while you're in school at least half-time, during the grace period, and during deferment. Unsubsidized loans accrue interest from the day they're disbursed. Both are available to undergraduates; only unsubsidized loans are available to graduate students.
What is Public Service Loan Forgiveness (PSLF)?
PSLF forgives the remaining federal loan balance after 120 qualifying monthly payments (10 years) while working full-time for a qualifying employer — government agencies, non-profits, or certain other public service organizations. The forgiven amount is not taxed as income.
Should I choose standard or income-driven repayment?
Standard repayment costs less in total interest and pays off the loan faster. IDR makes sense if your income is low relative to your debt, if you're pursuing PSLF, or if you need lower payments to cover essential expenses. You can switch plans later.
What is the SAVE plan?
SAVE (Saving on a Valuable Education) replaced REPAYE. It caps payments at 5% of discretionary income for undergraduate loans and 10% for graduate loans. Discretionary income is income above 225% of the federal poverty line. Remaining balance is forgiven after 20–25 years of payments.
How much do extra payments save on student loans?
Significant amounts. On a $35,000 loan at 5.50%, paying an extra $100/month saves about $3,090 in interest and pays off the loan 2.5 years early. An extra $200/month saves about $4,700 and cuts 4 years off the term. Earlier extra payments save more because they reduce the balance that accrues interest.
Should I refinance my student loans?
Refinancing can lower your rate on private loans if your credit has improved. However, refinancing federal loans into a private loan means permanently losing access to IDR plans, PSLF, and other federal protections like deferment and forbearance. Only refinance federal loans if you're certain you won't need those options.
Is student loan forgiveness taxable?
It depends on the program. PSLF forgiveness is tax-free. IDR forgiveness after 20–25 years may be treated as taxable income under current law, though temporary provisions have exempted it through 2025. Teacher Loan Forgiveness is also tax-free. Check current tax law for the year your forgiveness occurs.
Does this calculator store my financial information?
No. All calculations run entirely in your browser using JavaScript. No loan amounts, income figures, or personal data are sent to any server, stored in any database, or logged in any way. You can verify this by using the tool offline after the page loads.
Related Tools
- Loan Calculator — general-purpose loan payment and interest calculator
- Loan Amortization Schedule — see the full payment-by-payment breakdown
- Compound Interest Calculator — understand how interest compounds over time
- Debt Payoff Calculator — plan a strategy to eliminate debt faster
- Savings Goal Calculator — plan your savings after the loans are paid off
Privacy & Limitations
- Client-side only. No data is sent to any server. No loan balances, income, or personal information is stored, transmitted, or logged.
- Estimates, not guarantees. This calculator provides estimates based on the inputs you provide. Actual payments may vary based on your servicer's rounding, payment processing dates, and specific plan rules.
- IDR estimates are simplified. Real IDR payments depend on your adjusted gross income, family size, state of residence, and the specific plan's formula. Income typically changes over time, which affects payments year to year.
- Not financial advice. This tool is for educational and planning purposes. For decisions about your specific student loans, consult your loan servicer or a qualified financial professional.
- Federal rates are point-in-time. The interest rates shown are for the 2024-25 academic year. Federal rates are set annually by Congress. Check studentaid.gov for current rates.
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Student Loan Calculator FAQ
How do I calculate my student loan monthly payment?
Use the standard loan payment formula: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the loan balance, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12). For a $35,000 loan at 5.50% over 10 years, the monthly payment is $380.
How much total interest will I pay on my student loans?
Total interest depends on your balance, rate, and repayment term. On a $35,000 loan at 5.50% with standard 10-year repayment, you pay about $10,558 in interest — roughly 30% of the original loan. Extending to 20 years drops monthly payments but increases total interest to about $23,464.
What is the difference between standard and income-driven repayment?
Standard repayment uses fixed monthly payments over 10 years. Income-driven repayment (IDR) caps payments at a percentage of your discretionary income (5-20% depending on the plan) and extends the term to 20-25 years. IDR lowers monthly payments but increases total interest. Remaining balance may be forgiven after the repayment period.
What is Public Service Loan Forgiveness (PSLF)?
PSLF forgives the remaining federal loan balance after 120 qualifying monthly payments (10 years) while working full-time for a qualifying employer — government agencies, non-profits, or certain other public service organizations. The forgiven amount under PSLF is not taxed as income.
Should I refinance my student loans?
Refinancing can lower your interest rate on private loans if your credit has improved. However, refinancing federal loans into a private loan means losing access to income-driven repayment, PSLF, and other federal protections like deferment and forbearance. Consider keeping federal loans federal if you might need those options.
How does the interest rate affect total student loan cost?
Small rate differences add up significantly over time. On a $35,000 loan over 10 years, going from 5.50% to 7.05% increases total interest from $10,558 to $13,841 — an extra $3,283. Over 20 years, the same rate increase adds over $8,000 in extra interest.
What are current federal student loan interest rates?
For the 2024-25 academic year, federal rates are: Direct Subsidized/Unsubsidized loans for undergraduates at 5.50%, Direct Unsubsidized loans for graduate students at 7.05%, and Direct PLUS loans at 8.05%. Private loan rates vary by lender and credit profile, typically ranging from 4% to 14%.
What is the SAVE plan for student loans?
The SAVE (Saving on a Valuable Education) plan replaced REPAYE. It caps payments at 5% of discretionary income for undergraduate loans and 10% for graduate loans. Discretionary income is calculated as income above 225% of the federal poverty line. Remaining balance is forgiven after 20-25 years of payments.
How much do I save by paying extra on student loans?
Extra payments reduce principal faster, which reduces total interest. On a $35,000 loan at 5.50% over 10 years, paying an extra $100/month saves about $3,090 in interest and pays off the loan 2.5 years early. The earlier you make extra payments, the more interest you save.
Does this calculator store my financial information?
No. All calculations run in your browser using JavaScript. No loan amounts, income figures, or personal data are sent to any server, stored, or logged. You can verify this by using the tool offline after the page loads.