Loan Calculator
Work out the monthly payment on any loan — car, personal, student or mortgage — plus how much interest you'll pay in total and what happens if you overpay.
Fill in the fields to see your result.
Year-by-year breakdown
How the balance falls over the life of the loan, and how much of each year goes on interest.
How this loan calculator works
Nearly every loan you can take out — car finance, a personal loan, a student loan, a mortgage — is an amortising loan. You pay the same amount every month, and each payment is split two ways: part of it covers the interest the lender charges, and whatever's left knocks down the amount you actually owe.
At the start, most of your payment is interest. As the balance shrinks, less interest is charged, so more of each payment goes to the loan itself. That's why the year-by-year table above starts out looking discouraging and improves as you go.
The formula
The standard monthly payment formula is:
If the loan is genuinely interest-free, the formula collapses to M = P / n — you just split the amount over the months.
A worked example
Say you borrow 25,000 over 5 years at 7.5% a year.
- Monthly rate: 7.5 / 12 / 100 = 0.00625
- Number of payments: 5 x 12 = 60
- Monthly payment: about 501
- Total repaid: about 30,060, of which roughly 5,060 is interest
So the loan costs you about a fifth again on top of what you borrowed. That's the number most people never work out before signing.
What actually moves your monthly payment
| If you change this | Monthly payment | Total interest |
|---|---|---|
| Borrow less | Goes down | Goes down |
| Longer term | Goes down | Goes up, often a lot |
| Lower interest rate | Goes down | Goes down |
| Pay extra each month | Goes up now | Goes down, loan ends sooner |
The one that catches people out is the term. Stretching a loan from 3 years to 6 makes the monthly payment look comfortable, but you can easily end up paying double the interest for the privilege. Run both in the calculator before you decide.
Three ways to pay less interest
- Overpay, even slightly. Put a small amount in the "extra payment" box above. Because every extra unit comes straight off the balance, the interest saved is usually far bigger than the extra you put in.
- Shorten the term instead of taking the low payment. If you can afford the higher monthly amount, a shorter loan is almost always cheaper overall.
- Check for early-repayment fees first. Some lenders charge a penalty for clearing a loan early, which can cancel out the saving. It'll be in your loan agreement.
Frequently asked questions
Does this calculator work for a mortgage?
For the loan part, yes — a repayment mortgage uses exactly the same maths. But a mortgage also comes with property tax, building insurance and sometimes service charges, which this page doesn't include. Use our mortgage calculator instead if you want the full monthly figure.
What's the difference between the interest rate and the APR?
The interest rate is just the cost of borrowing the money. The APR also folds in compulsory fees, so it's usually slightly higher and it's the fairer number to compare lenders with. If your lender gave you an APR, use that here for a more realistic result.
Why is so much of my early payment going to interest?
Interest is charged on what you still owe, and at the start you still owe almost everything. As the balance falls, the interest portion falls with it and more of the same payment starts clearing the actual loan. The year-by-year table on this page shows that shift happening.
Is paying extra each month really worth it?
Usually, yes — and the calculator shows you exactly how much. Extra payments come straight off the balance, so they stop interest being charged on that money for the rest of the loan. Just check your agreement for early-repayment penalties first, and make sure the lender applies overpayments to the balance rather than to future payments.
Does the calculator handle interest-free loans?
It does. Enter 0 as the interest rate and it simply divides the amount by the number of months. Worth knowing: a genuine 0% deal often has a fee or a higher cash price attached, so compare the total repaid, not the rate.
Are my numbers sent anywhere?
No. Everything is worked out inside your own browser. Nothing you type is uploaded, stored or shared, and there's no sign-up.
Please note: CalcuLane gives estimates for general information only and is not financial advice. Lenders round differently, and fees, insurance and payment-date rules can change what you actually pay. Always confirm figures with your lender before committing to a loan.