About this tool
Calculate a practical loan payment estimate, preview amortization, and see how extra monthly payments reduce total interest.
Loan Calculator builds a month-by-month repayment schedule for a fixed-rate loan and reports the numbers people usually need before signing: the contractual monthly payment, the planned payment when you add an extra amount, total interest over the life of the loan, payoff time, and how much interest and time a recurring overpayment saves. It works in seven currencies (USD, KRW, EUR, GBP, JPY, CAD, AUD) and rounds interest to that currency's smallest unit each month, which keeps totals consistent with how a statement would print them. Monthly taxes and insurance can be added to see an all-in monthly figure. The results are arithmetic illustrations of a simple amortization model, not lending, tax, or financial advice, and they are not a quote.
- Calculates monthly payment from principal, annual interest rate, and term length.
- Shows total repayment, total interest, and payoff time.
- Previews the early amortization schedule and extra-payment savings.
How to use Loan Calculator
Start by choosing a Currency, which sets decimal precision and formatting but does not convert amounts. For a starting point, pick a scenario from Load a market example, such as a 30-year mortgage or a 5-year auto loan, and edit from there. Enter the Loan amount, the annual Interest rate % (up to three decimals), and the Term in years as a whole number from 1 to 50. Add an Extra monthly payment to model overpaying, and fill in Monthly taxes and Monthly insurance for the all-in cost. The right panel recalculates as you type, showing the planned payment, a decision summary, and the first twelve schedule rows with payment, principal, interest, and balance. Inputs are mirrored into the page URL, so copying the link shares the scenario.
When this tool is useful
- A first-time car buyer comparing a 48-month and a 60-month term at the dealer's quoted rate before agreeing to either.
- A homeowner deciding whether adding 200 a month to a mortgage is worth it in interest saved and years cut.
- A small-business owner estimating the monthly cash-flow impact of an equipment loan before applying.
- A personal-finance coach walking a client through how principal share grows in the first year of a loan.
- A renter in Korea or Japan checking a zero-decimal currency schedule without fiddling with rounding in a spreadsheet.
Practical tips
- Change one input at a time when comparing scenarios; the URL updates with each change, so you can bookmark two versions and flip between them.
- Watch the First-payment principal share figure. On long terms it is often under 20 percent, which explains why early extra payments have an outsized effect.
- Taxes and insurance are added flat to the monthly total and never amortize, so they raise the all-in cost without changing payoff time.
- The model assumes a fixed nominal annual rate divided by twelve. Lenders using daily accrual, different compounding, or fees will produce slightly different figures.
- Adjustable-rate, interest-only, balloon, and irregular-payment loans are not modeled; use this for fixed-rate, level-payment loans only.
Loan over 5 years: monthly payment examples
The table below shows 60-month repayments at a 7% fixed annual rate, calculated with the same monthly rounding the calculator uses. The figures are the same in pounds, dollars, or euros because the currency only changes formatting, so a £34,000 loan over 5 years and a $34,000 loan over 5 years both cost about 673.25 a month at this rate. Enter your quoted rate to replace the 7% assumption.
- UK lenders quote a representative APR that can include fees, so the payment on an offer can differ from this fixed nominal-rate model.
- Each extra year on the term lowers the monthly payment but raises total interest; compare both before choosing.
| Loan amount | Monthly payment | Total interest | Total repaid |
|---|---|---|---|
| Loan amount10,000 | Monthly payment198.02 | Total interest1,880.67 | Total repaid11,880.67 |
| Loan amount15,000 | Monthly payment297.02 | Total interest2,821.04 | Total repaid17,821.04 |
| Loan amount19,000 | Monthly payment376.23 | Total interest3,573.30 | Total repaid22,573.30 |
| Loan amount25,000 | Monthly payment495.04 | Total interest4,701.69 | Total repaid29,701.69 |
| Loan amount30,000 | Monthly payment594.04 | Total interest5,642.12 | Total repaid35,642.12 |
| Loan amount34,000 | Monthly payment673.25 | Total interest6,394.30 | Total repaid40,394.30 |
| Loan amount40,000 | Monthly payment792.05 | Total interest7,522.85 | Total repaid47,522.85 |
| Loan amount50,000 | Monthly payment990.06 | Total interest9,403.55 | Total repaid59,403.55 |
| Loan amount70,000 | Monthly payment1,386.09 | Total interest13,164.95 | Total repaid83,164.95 |
Examples you can test
Load an example, compare the result with the expected output, then replace it with your own input.
Five-year auto loan with a small overpayment
Example input
USD, 32,000 loan, 4.9% rate, 5 years, extra 50 per month
Expected output
Contractual payment around 602; planned payment 652; payoff a few months early with a modest interest saving
This is the built-in USD auto example. The decision summary shows both Interest saved with extra and Time saved with extra so the trade-off is visible.
Thirty-year mortgage all-in cost
Example input
USD, 450,000 loan, 6.25% rate, 30 years, taxes 420, insurance 110
Expected output
Principal and interest near 2,771 per month; all-in about 3,301 with tax and insurance
Figures come from the simple monthly model with half-up rounding per payment; a lender's escrow and fee schedule will differ, so treat this as a planning illustration.
Validation checklist
- Confirm the rate is an annual percentage, not a monthly one, and has at most three decimals.
- Check that the term is entered in whole years, since months are not accepted.
- Compare total interest, not just the monthly payment, when weighing a longer term.
- Remember the schedule is a simple fixed-rate illustration and not a lender quote.
- Clear sensitive amounts from the URL before sharing a link, since inputs are stored in query parameters.