Student loan payment calculator

Estimate the fixed monthly payment on a student loan under standard repayment, and see how much of your total payments go to interest.

How this calculator works

The US standard repayment plan for federal student loans spreads the balance evenly over ten years with a fixed payment. Private student loans often use the same amortisation but may have shorter or longer terms, variable rates and different deferment rules. This calculator models the classic fixed-rate, fully amortising case so you can see what standard repayment actually costs.

Two things are not modelled because they depend on your specific situation: income-driven repayment (which caps payments at a percentage of discretionary income for 20–25 years) and forgiveness programmes. Both can change the total dramatically, but they also depend on eligibility and tax rules that no simple formula can capture.

The formula

Standard amortisation with P = balance, r = APR ÷ 12 ÷ 100 and n = months in the term:

Interest is charged on the outstanding balance each month. During any deferment or forbearance period interest may still accrue, so the starting balance in repayment can be higher than what you originally borrowed — use the post-graduation balance here.

Worked example

A 40,000 student loan at 5.50% over 10 years requires $434.11 a month. The total repaid is $52,092.61, which means $12,092.61 of interest on top of the balance.

Common mistakes

• Using the pre-graduation balance. If interest was capitalised during school or a grace period, the repayment balance is larger. Start from the actual figure your servicer reports.
• Assuming income-driven plans are cheaper overall. Lower monthly payments usually mean a longer term and more interest, and forgiveness may be taxable depending on the programme and your jurisdiction.
• Ignoring the interest deduction. In the US, some student loan interest is tax-deductible (subject to income limits), which slightly reduces the true cost. This calculator shows the gross cost.