How does the calculator work out your student loan payment?
It divides your annual rate by 12 to get a monthly rate and multiplies the repayment term by 12 to count payments. The amortization formula then produces the fixed monthly payment that pays the balance and all interest by the end of the term.
Each month, interest is charged on the remaining balance, and the rest of the payment reduces principal. Early on, more of the payment goes to interest; by the final years, nearly all of it goes to principal.
Total repaid is the payment times the number of payments. Total interest is total repaid minus the starting balance. If you have several loans at different rates, run each one separately or use a weighted-average rate as an approximation.
M = B × r × (1 + r)^n ÷ ((1 + r)^n − 1) Total repaid = M × n Total interest = M × n − B
- M
- monthly payment
- B
- current loan balance
- r
- monthly rate (annual rate ÷ 12)
- n
- number of monthly payments
Example: $36,400 at 6.53% on a 10-year schedule
Scenario: A recent graduate owes $36,400 across undergraduate loans at an illustrative blended 6.53% fixed rate and is choosing a standard 10-year repayment schedule.
- Monthly rate6.53% ÷ 12 ≈ 0.54417% (0.0054417)
- Number of payments10 years × 12 = 120
- Monthly payment$36,400 over 120 months at 0.54417% = $413.87
- First month's interest$36,400 × 0.0653 ÷ 12 = $198.08, so $215.79 goes to principal
- Total repaid$413.87 × 120 = $49,664.40
- Total interest$49,664.40 − $36,400 = $13,264.40
The 10-year payment is $413.87 a month, with $13,264.40 of interest and $49,664.40 repaid in total.
If several loans carry different rates, the blended figure is an approximation; your servicer bills each loan at its own rate.
When is this student loan calculator the right tool?
Before your first payment is due
Running your balance on a 10-year schedule gives a baseline for your post-graduation budget. You can then compare it with any plan your servicer offers.
Considering a longer repayment plan
Plugging in 15, 20 or 25 years shows how much the lower payment adds in interest.
Planning to pay extra
Compare the scheduled payment with what you can afford. The gap is what you could put toward principal each month.
Evaluating a private refinance
Enter the offered rate and term to see the new payment and total interest. Remember that refinancing federal loans privately gives up federal protections.
What student loan estimate mistakes are common?
Using the original borrowed amount
Interest that accrued during school or deferment may have been added to principal. Use the payoff balance your servicer shows.
Assuming one rate for all loans
Federal loans from different years often carry different rates. A single blended rate is only an approximation.
Applying this formula to an income-driven plan
Income-driven payments are set as a share of income, not by amortization. The calculator shows the standard-schedule alternative.
Letting extra payments go to future bills
Some servicers advance your due date instead of reducing principal. Ask that extra be applied to principal on the highest-rate loan.
Overlooking the interest deduction
Student loan interest may be deductible up to an annual cap, which slightly lowers your after-tax cost. Eligibility depends on income and filing status.
How much does a longer repayment term cost?
Stretching $36,400 at 6.53% from 10 to 20 years drops the payment from $413.87 to $272.03, but total interest more than doubles, from $13,264.40 to $28,887.20. At 25 years, interest reaches $37,538.00, more than the amount borrowed.
Going the other way works too. Adding $100 a month to the 10-year payment, for $513.87 in total, clears the loan in 90 months instead of 120 and cuts interest to about $9,702.77, assuming the extra goes to principal each month.
| Repayment term | Monthly payment | Total interest | Total repaid |
|---|---|---|---|
| 10 years | $413.87 | $13,264.40 | $49,664.40 |
| 15 years | $317.68 | $20,782.40 | $57,182.40 |
| 20 years | $272.03 | $28,887.20 | $65,287.20 |
| 25 years | $246.46 | $37,538.00 | $73,938.00 |
Terms used on this page
- Amortization
- Amortization is the process of paying off a loan with equal, regular payments that each cover the interest due for the period plus a slice of principal. Early payments are mostly interest; later ones are mostly principal. By the final payment the balance reaches exactly zero, which is how most car, personal and student loans work.
- Capitalized Interest
- Capitalized interest is unpaid interest that gets added to a loan's principal balance. After capitalization, you pay interest on that interest, which raises both your payment and total cost. It commonly happens with student loans after periods when payments are paused, such as school, a grace period or certain forbearance and deferment periods.
- Loan Term
- The loan term is the length of time you have to repay a loan, usually stated in months for consumer loans. A longer term lowers the monthly payment but increases the total interest you pay, because the balance stays outstanding longer. A shorter term costs more each month and less overall.
- Debt Avalanche
- The debt avalanche is a payoff strategy where you pay the minimum on every debt and put all extra money toward the balance with the highest interest rate first. When that debt is gone, its payment rolls to the next-highest rate. Mathematically, it usually minimizes total interest and often finishes as fast or faster than other orders.
- Interest Rate
- An interest rate is the price of money, stated as a percentage of the balance per year. Borrowers pay it to lenders, and savers earn it from banks. The rate alone does not include fees or compounding, so it can understate the true yearly cost of a loan or overstate a simple comparison of savings accounts.
Student Loan Calculator: common questions
How much is the monthly payment on a $36,000 student loan?
It depends on the rate and term. At an illustrative 6.53% over the standard 10 years, $36,400 costs $413.87 a month; stretched to 20 years, about $272.03. Enter your own balance and rate to get your figure, and remember that income-driven plans can produce a very different payment. Federal loans from different years may carry different rates.
How long does it take to pay off student loans?
On the standard federal schedule, 10 years. Longer plans and some consolidation terms extend repayment to 20 or 25 years. Paying more than the scheduled amount shortens any of these; even a modest extra payment each month can take a year or more off a 10-year loan, depending on the balance and rate.
Is it better to pay off student loans early?
Paying early saves interest, and the saving is larger on higher-rate loans. Whether it is the best use of your money depends on your other priorities, such as building an emergency fund or paying down higher-rate debt. For federal loans, also consider whether you are working toward a forgiveness program before prepaying.
Does student loan interest accrue while I'm in school?
On many loans, yes. Unsubsidized federal loans and most private loans accrue interest from disbursement, and unpaid interest may be capitalized when repayment begins. Subsidized federal loans do not accrue interest while you are enrolled at least half time. That is why your starting balance can be higher than what you borrowed.
Can I deduct student loan interest on my taxes?
Possibly. The federal student loan interest deduction lets eligible borrowers deduct up to $2,500 of interest paid each year, without itemizing. It phases out at higher incomes and has filing-status rules. The IRS publishes the current limits, and your servicer reports the interest you paid on Form 1098-E. The deduction lowers taxable income, not your loan balance.
Should I pick a longer term to lower my payment?
It can make the budget work, but it costs more. On the $36,400 example, moving from 10 to 15 years lowers the payment by $96.19 a month and adds $7,518.00 in interest. If you choose the longer term, paying extra when you can recovers some of that cost. Federal loans carry no prepayment penalty.
Which student loan should I pay extra on first?
Putting extra toward the highest-rate loan saves the most interest, an approach often called the avalanche method. Paying off the smallest balance first frees up a payment sooner and can help motivation. Either way, tell your servicer which loan the extra is for, or it may be spread across all of them.
Does this calculator handle income-driven repayment?
No. Income-driven plans set payments as a share of discretionary income and may forgive a remaining balance after many years, so they do not follow the fixed amortization formula used here. Use your servicer's tools for those figures, and rely on this calculator for the standard-schedule cost as a comparison. Comparing both can show how much an income-driven plan might cost over time.
Are federal student loan rates fixed?
Federal student loans made in recent decades carry fixed rates for the life of each loan, with new rates set each year for new loans. Private student loans may be fixed or variable. If yours is variable, the payment here is accurate only while the rate stays the same. Rerun the calculator if a variable rate changes.
Sources
- Student loan repayment plans — Federal Student Aid (U.S. Department of Education). Accessed October 17, 2026.
- Federal student loan interest rates — Federal Student Aid (U.S. Department of Education). Accessed October 17, 2026.
- Student loans — Consumer Financial Protection Bureau. Accessed October 17, 2026.
- Topic no. 456, Student loan interest deduction — Internal Revenue Service. Accessed October 17, 2026.
We cite primary sources: regulators, central-bank data and federal agencies. Worked examples on this page are our own calculations, last checked October 17, 2026. See our methodology.