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Student loan — payment, interest and total
A student loan is priced on three numbers: how much you borrow, the APR, and how many years you take to repay it. The calculator works out all three, plus what the first payment is made of.
★ MONEY · LOANS · STUDENT LOANS
Student Loan Calculator: Payment, Interest & Total 2026
A $30,000 loan at 6.5% for 10 years costs $340.64 a month. The total paid is $40,877.27 and the interest is $10,877.27. Enter your loan amount, APR and term to work out your payment, your total and your interest.
How a student loan payment is worked out
A student loan payment is priced on three numbers: how much you borrow, the APR, and how many years you take to repay it. The monthly rate is the APR divided by 12, the number of payments is the years times 12, and the payment is the loan times the monthly rate times (1 + rate) to the power of the payments, divided by (1 + rate) to the power of the payments minus 1. The total paid is the payment times the number of payments, and the interest is the total paid minus the loan.
At the defaults — loan $30,000, APR 6.5%, term 10 years — the monthly rate is 6.5% ÷ 12 = 0.5417%, the payments are 120, and the payment is $340.64 a month. The total paid is $340.64 × 120 = $40,877.27, and the interest is $40,877.27 − $30,000 = $10,877.27. The first payment is $162.50 interest and $178.14 principal, the first year costs $1,885.15 of interest, and the last year costs $140.36.
| Case | Monthly payment | Total paid | Interest |
|---|---|---|---|
| Default ($30,000, 6.5%, 10 yr) | $340.64 | $40,877.27 | $10,877.27 |
| $20,000 loan | $227.10 | $27,251.51 | $7,251.51 |
| $50,000 loan | $567.74 | $68,128.79 | $18,128.79 |
| APR 4.5% | $310.92 | $37,309.83 | $7,309.83 |
| APR 8.5% | $371.96 | $44,634.85 | $14,634.85 |
| Term 5 years | $586.98 | $35,219.07 | $5,219.07 |
| Term 20 years | $223.67 | $53,681.27 | $23,681.27 |
| Term 25 years | $202.56 | $60,768.64 | $30,768.64 |
The worked example, line by line
Setup: loan $30,000, APR 6.5%, term 10 years.
Line 1 — the monthly rate. 6.5% ÷ 12 = 0.5417% a month, or 0.0054167.
Line 2 — the number of payments. 10 years × 12 = 120 payments. The payoff month is the first payment month plus 120 months.
Line 3 — the growth factor. (1 + 0.0054167)^120 = 1.91218. A longer term makes it bigger — at 5 years it is 1.38282, at 20 years it is 3.65645, at 25 years it is 5.05620 — and a higher rate makes it bigger faster.
Line 4 — the monthly payment. $30,000 × 0.0054167 × 1.91218 ÷ (1.91218 − 1) = $162.50 × 1.91218 ÷ 0.91218 = $340.64 a month.
Line 5 — the total paid. $340.64 × 120 = $40,877.27.
Line 6 — the interest. $40,877.27 − $30,000 = $10,877.27.
Line 7 — the first payment. The first month’s interest is $30,000 × 0.0054167 = $162.50, so the principal in the first payment is $340.64 − $162.50 = $178.14. The first year costs $1,885.15 of interest, and the last year costs $140.36, because the balance is nearly gone by then.
Every branch, checked
$20,000 loan: the payment is $227.10 a month, the total paid is $27,251.51, and the interest is $7,251.51. Borrowing a third less cuts the payment by $113.54 a month, because the payment scales with the loan at the same rate and term.
$50,000 loan: the payment is $567.74 a month, the total paid is $68,128.79, and the interest is $18,128.79. Borrowing $20,000 more costs $227.10 a month more, because the payment is the loan times the same factor.
APR 4.5%: the payment is $310.92 a month, the total paid is $37,309.83, and the interest is $7,309.83. A rate 2 points lower saves $29.72 a month and $3,567.44 of interest over 10 years.
APR 8.5%: the payment is $371.96 a month, the total paid is $44,634.85, and the interest is $14,634.85. A rate 2 points higher costs $31.32 a month more and $3,757.58 of interest over 10 years.
Term 5 years: the payment is $586.98 a month, the total paid is $35,219.07, and the interest is $5,219.07. Halving the term raises the payment by $246.34 a month but saves $5,658.20 of interest, because the loan is paid off in half the time.
Term 20 years: the payment is $223.67 a month, the total paid is $53,681.27, and the interest is $23,681.27. A longer term cuts the payment by $116.97 a month but costs $12,804.00 of extra interest, because the loan runs a decade longer.
Term 25 years: the payment is $202.56 a month, the total paid is $60,768.64, and the interest is $30,768.64. Twenty-five years cuts the payment by $138.08 a month against 10 years but costs $19,891.37 of extra interest, because the balance stays high for decades.
Reverse — the loan a monthly payment affords: $250 a month affords a $22,017.12 loan, $400 a month affords $35,227.40, and $500 a month affords $44,034.25, all at 6.5% for 10 years. Work backwards from the payment when the budget is fixed: the loan is the payment times the same factor in reverse.
What the defaults assume
The model assumes a fixed APR for the whole term, with the same payment every month, and it assumes the loan is paid off in equal monthly payments with no extra payments, no fees and no origination charge. It assumes the APR is the rate that prices the loan, which is how federal student loans are quoted, and it leaves out income-driven repayment plans, deferment and forbearance, forgiveness programs, and the interest that accrues while you are in school on unsubsidized loans. It does not say whether a lender will approve you: private lenders check your credit, your income and your co-signer before they lend. Rounding convention: money is rounded to cents, and all figures are computed from unrounded values, rounded only for display.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Monthly payment | loan × r × (1+r)^n ÷ ((1+r)^n − 1) | $340.64 a month. |
| Total paid | payment × n | $40,877.27. |
| Total interest | total paid − loan | $10,877.27. |
| First payment interest | loan × r | $162.50. |
| First payment principal | payment − first interest | $178.14. |
| Interest in the first year | sum of the first 12 months’ interest | $1,885.15. |
| Interest in the last year | sum of the last 12 months’ interest | $140.36. |
| $20,000 loan | same model, $20,000 | $227.10/mo, $27,251.51 total, $7,251.51 interest. |
| $50,000 loan | same model, $50,000 | $567.74/mo, $68,128.79 total, $18,128.79 interest. |
| APR 4.5% | same model, 4.5% | $310.92/mo, $37,309.83 total, $7,309.83 interest. |
| APR 8.5% | same model, 8.5% | $371.96/mo, $44,634.85 total, $14,634.85 interest. |
| Term 5 years | same model, 5 years | $586.98/mo, $35,219.07 total, $5,219.07 interest. |
| Term 20 years | same model, 20 years | $223.67/mo, $53,681.27 total, $23,681.27 interest. |
| Term 25 years | same model, 25 years | $202.56/mo, $60,768.64 total, $30,768.64 interest. |
| Reverse: $250/mo affords | payment × ((1+r)^n − 1) ÷ (r × (1+r)^n) | $22,017.12. |
| Reverse: $400/mo affords | same inverse formula | $35,227.40. |
| Reverse: $500/mo affords | same inverse formula | $44,034.25. |
Who uses this
- The recent graduate: they learn a $30,000 loan costs $340.64 a month and $10,877.27 of interest over 10 years — so they know the true cost of the degree, and they check the $50,000 loan at $567.74 a month before borrowing more.
- The borrower comparing rates: they learn 4.5% costs $310.92 a month against $371.96 at 8.5% — so they know a 4-point rate gap is worth $61.04 a month, and they check the $7,309.83 of interest against the $14,634.85, a gap of $7,325.02, before they sign.
- The borrower choosing a term: they learn 5 years costs $586.98 a month and $5,219.07 of interest against $202.56 a month and $30,768.64 of interest at 25 years — so they know the short term saves $25,549.57 of interest, and they check the $384.42 a month against their budget.
- The borrower working from a monthly budget: they learn $400 a month affords a $35,227.40 loan — so they know what their budget buys, and they check the $500 a month at $44,034.25 before they stretch.
Accuracy & limitations
The math is exact for the numbers you enter: the payment follows the standard loan formula, the total paid is the payment times the months, the interest is the total minus the loan, and the first payment’s interest is the loan times the monthly rate. What the model cannot do is read your loan offer for you: check the APR on the offer, because a 4.5% offer and an 8.5% offer give very different payments, and check whether interest accrues while you are in school, which this calculator leaves out. It assumes a fixed APR, equal monthly payments, no extra payments, no fees and no income-driven plan, and it leaves out deferment, forbearance and forgiveness. For the payment schedule, see amortization schedule calculator; for the personal loan, see personal loan calculator.
Cite this calculatorBright Side Kit. “Student Loan Calculator: Payment, Interest & Total 2026.” brightoolbox.com, 2026. Method: Monthly rate r = APR ÷ 12; n = years × 12; payment = loan × r × (1+r)^n ÷ ((1+r)^n − 1); total paid = payment × n; total interest = total paid − loan; first payment interest = loan × r; first payment principal = payment − first interest. Defaults: loan $30,000, APR 6.5%, term 10 years → monthly rate 0.5417%, payment $340.64, total $40,877.27, interest $10,877.27; first payment $162.50 interest and $178.14 principal; first-year interest $1,885.15; last-year interest $140.36; 120 payments. Branches: $20,000 loan → $227.10/mo, $27,251.51 total, $7,251.51 interest; $50,000 loan → $567.74/mo, $68,128.79 total, $18,128.79 interest; APR 4.5% → $310.92/mo, $37,309.83 total, $7,309.83 interest; APR 8.5% → $371.96/mo, $44,634.85 total, $14,634.85 interest; term 5 yr → $586.98/mo, $35,219.07 total, $5,219.07 interest; term 20 yr → $223.67/mo, $53,681.27 total, $23,681.27 interest; term 25 yr → $202.56/mo, $60,768.64 total, $30,768.64 interest. Reverses: $250/mo → $22,017.12; $400/mo → $35,227.40; $500/mo → $44,034.25.
Bright Side Kit. "Student Loan Calculator: Payment, Interest & Total 2026." https://brightoolbox.com/student-loan-calculator/ Accessed October 25, 2026.Frequently asked questions
How do you calculate a student loan payment?
Loan times the monthly rate factor. The monthly rate is 6.5% divided by 12, which is 0.5417%, the payments are 120, and the payment is $30,000 times 0.0054167 times (1.0054167) to the power of 120, divided by (1.0054167) to the power of 120 minus 1, which is $340.64 a month. The total paid is $340.64 times 120, which is $40,877.27.
How much interest will I pay on a $30,000 student loan?
$10,877.27 at 6.5% for 10 years. The total paid is $40,877.27, and the interest is $40,877.27 minus $30,000, which is $10,877.27. At 4.5% the interest is $7,309.83, and at 8.5% it is $14,634.85, so the rate matters more than the loan amount.
What is the monthly payment on a $30,000 student loan?
$340.64 a month at 6.5% for 10 years. At 4.5% it is $310.92 a month, and at 8.5% it is $371.96 a month. Over 5 years it is $586.98 a month, and over 25 years it is $202.56 a month.
How much of my first payment is interest?
$162.50 of the first $340.64. The first month’s interest is $30,000 times 0.5417%, which is $162.50, so the principal in the first payment is $340.64 minus $162.50, which is $178.14. The first year costs $1,885.15 of interest, and the last year costs $140.36, because the balance is nearly gone by then.
Is a shorter term always better for a student loan?
For interest, yes; for the monthly budget, not always. A 5-year term costs $5,219.07 of interest against $10,877.27 at 10 years, so it saves $5,658.20, but the payment is $586.98 a month against $340.64. A 25-year term cuts the payment to $202.56 a month but costs $30,768.64 of interest. Pick the shortest term whose payment fits the budget.
How much can I borrow with a $400 monthly payment?
$35,227.40 at 6.5% for 10 years. A $250 a month payment affords $22,017.12, and $500 a month affords $44,034.25, at the same rate and term. Work backwards from the payment when the budget is fixed.
What does the payment leave out?
Interest in school, income-driven plans and forgiveness. The $340.64 a month is the standard-plan payment only: it leaves out the interest that accrues on unsubsidized loans while you are in school, and any income-driven repayment plan, which changes the payment. A $30,000 loan costs $40,877.27 in loan payments over 10 years on the standard plan.
Student loan vs personal loan: which costs less?
Usually the student loan. A student loan at 6.5% costs $10,877.27 of interest on $30,000 over 10 years, while a personal loan at 10.5% would cost far more for the same balance, because the rate is higher. A student loan also offers income-driven plans and forgiveness options a personal loan does not.