Loan Repayment Calculator
Compare the monthly payment and total interest of three repayment methods at once.
| Total repaid | |
| Total interest | |
| Compare methods | |
| Equal payments: total interest | |
| Equal principal: total interest | |
| Interest-only: total interest |
How it works
The calculator works in any currency: type the amount in your own money and read the results in the same unit. Even with the same 300,000 loan at 4% over 30 years, the repayment method can change your total interest by tens of thousands. If you want predictable, lower early payments, choose equal payments. If you can afford higher payments at the start and want to pay the least interest overall, equal principal wins.
To see how saved money grows instead, try the compound interest calculator or the savings interest calculator. For quick rate maths, use the percentage calculator.
Frequently asked questions
What is the difference between equal payments and equal principal?
With equal payments (a standard amortizing loan or mortgage), you pay the same amount every month, so budgeting is easy. With equal principal, you repay the same slice of principal each month plus interest on what is left, so early payments are higher but the total interest is lower.
When does an interest-only (bullet) loan make sense?
You pay only interest each month and repay the whole principal at the end. It suits short-term loans or cases where you expect a lump sum at maturity, such as a bridge loan before a property sale. It costs the most interest of the three methods.
How is the monthly payment calculated?
For equal payments the formula is P x r x (1 + r)^n / ((1 + r)^n - 1), where P is the loan amount, r is the annual rate divided by 12 and n is the number of months. For example, 300,000 at 4% over 30 years comes to about 1,432 per month.
Does this include fees, insurance or property tax?
No. It covers principal and interest only. Origination fees, mortgage insurance, property tax, early repayment penalties and variable rates will change what you actually pay, so check the final terms with your lender.
Estimates only. Real loans vary with rate changes, grace periods, fees and local rules. Confirm the exact terms with your lender.