Loan Calculator
Work out monthly payments and total interest for a mortgage or loan, with equal payments or equal principal, grace periods, stepped rates and a full schedule.
The same payment every month (recalculated when the rate changes); early payments are mostly interest.
Results
Enter the loan amount, term and rate to see the monthly payment and total interest.
How to use
- Enter the loan amount and choose equal payments or equal principal.
- Pick years or months, then enter the term and, if you have one, the grace period during which you only pay interest.
- Enter the annual rate. For stepped rates, click “Add rate stage”, e.g. 1.775% at first and 2.06% from year 3.
- You get the monthly payment, total interest and total paid. The schedule below is grouped by year; expand a year to see every month, or download it as CSV for a spreadsheet.
FAQ
What is the difference between equal payments and equal principal?
With equal payments (a standard amortizing loan) you pay the same amount every month; early payments are mostly interest. With equal principal you repay the same principal each month and interest falls with the balance, so payments shrink over time. It costs more at first but less interest overall.
What is a grace period?
During a grace period you pay only interest, which lowers the first years’ payments. Afterwards the whole principal has to be repaid over fewer months, so payments jump and total interest grows.
How are stepped rates handled?
Each month’s interest uses that month’s rate. With equal payments, the payment is recalculated from the remaining balance and months whenever the rate changes; with equal principal only the interest changes. Real loans often float with a benchmark rate, so treat the result as an estimate.
How is rounding handled?
Monthly interest = balance × annual rate ÷ 12, rounded half up to whole units; the equal payment is rounded the same way and principal = payment − interest. The last payment repays the remaining balance and so absorbs all earlier rounding, which is why it can differ slightly. Lenders that charge interest by the day may differ a little.
What is the formula for the monthly payment?
Payment = principal × r ÷ (1 − (1 + r)^−n), where r is the annual rate ÷ 12 and n the number of months. A 1,000,000 loan at 2% over 20 years (240 months) costs about 5,059 a month.
Is my data uploaded?
No. Everything is calculated in your browser, and the CSV is created on your device.
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