Finance calculators

Which one you need

If you are borrowing a fixed amount and paying it back in equal instalments — a car, a personal loan, a phone contract spread over two years — the loan calculator is the one. It gives the monthly payment, what the loan costs in interest overall, and the schedule showing how each payment splits between interest and capital. The mortgage calculator does the same arithmetic over the longer terms a house needs, where the split at the start is lopsided enough to surprise people.

If money is going the other way — sitting in an account or an index fund and growing — use the compound interest calculator. It takes a starting balance, a monthly contribution and a rate, and shows the balance year by year, separating what you put in from what the interest added. The percentage calculator is for the smaller questions that come up around all of this: a deposit as a percentage of a price, a rate rise expressed as a change, a discount worked backwards.

How the monthly payment is worked out

Every fixed-rate loan on this site uses the standard amortization formula. The payment P on a principal L, at a monthly rate i (the annual rate divided by twelve), over n months, is P = L × i / (1 − (1 + i)⁻ⁿ). That single number stays the same for the life of the loan, but what it buys changes every month: interest is charged on whatever you still owe, so early payments are mostly interest and late ones are mostly capital. This is why overpaying in year one saves far more than overpaying in year ten, and why the amortization table is more useful than the headline payment.

Compound growth is the same idea pointed forwards. A balance grows by its rate each period, and any regular contribution joins in and starts earning too. Because each period compounds on the last, the shape is a curve rather than a line, and the contributions you make earliest do the most work — the reason the year-by-year table matters more than the final figure.

Why your bank's number will differ

These calculators model the loan itself, nothing else, and a real quote is never just the loan. Lenders add arrangement and origination fees, some of which are financed into the balance so they quietly attract interest of their own. A mortgage payment usually bundles property tax and insurance into an escrow amount that has nothing to do with the interest rate. Rates are advertised in different conventions — nominal, effective, APR — and APR deliberately folds fees back in, so it will not match a rate you type here. Lenders also round in their own directions and count days per month differently.

Expect the figures here to land close to a real quote and not on top of it. They are for deciding whether a term or a deposit is worth pursuing, and for checking that a number someone told you is roughly the right shape. The binding number is the one in the offer document.

Questions people ask

Is anything I type sent anywhere?

No. The arithmetic runs in JavaScript inside your own tab, and there is no server behind these pages to receive a salary, a house price or a loan balance. Nothing is written to cookies or local storage either, so the figures are gone the moment you close the tab. You can confirm it in a few seconds: open your browser's developer tools, switch to the network panel, and fill in a calculator — the request list stays empty.

What is an amortization schedule for?

It is the month-by-month breakdown of where each payment goes, and it answers questions the monthly figure cannot. How much do I still owe after three years, if I want to sell or refinance? How much interest have I actually paid so far? What happens to the total if I add fifty a month? The schedule makes the interest cost visible as it accrues instead of hiding it inside one number at the end.

Does the loan calculator work for an EMI?

Yes — EMI, or equated monthly instalment, is the term used in India and parts of Asia for exactly this calculation, and the formula is identical. Enter the principal, the annual interest rate and the term in months or years, and the monthly payment it returns is the EMI. The amortization table is the same one your lender would produce.

Do these handle currencies other than dollars?

The maths is currency-agnostic, so enter your amounts in whatever currency you are working in and read the results in the same one. There is no conversion and no exchange rate involved. What the calculators do not model is anything specific to a country's lending rules — stamp duty, mortgage insurance thresholds, tax relief on interest — so treat those as separate line items.