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Loan calculator

The monthly payment is what sellers show you. The total cost is what you actually pay. See both.

Check your contract for early-repayment fees first

Monthly payment

Total interest
Total paid
Paid off in

YearInterestLoan repaidStill owed
My money plan

Next step: Already paying several debts? Compare the avalanche and snowball order: Debt payoff calculator →

How to use the calculator

  1. Enter the Amount to borrow: the loan itself, not the price of what you're buying if you pay part in cash.
  2. Enter the Interest rate per year from the offer. If the offer shows an APR, use that: it includes most fees and makes offers comparable.
  3. Set the Length in months. Longer means a lower monthly payment but more interest in total.
  4. Optionally set Extra each month to see how much time and interest overpaying saves. Check first that your contract allows early repayment and whether it charges a fee.
  5. Read the monthly payment, total interest and total paid, then the year-by-year table showing how much of each year's payments go to interest versus the loan itself.

What it's good for

  • Shows the full cost of borrowing, not just the monthly payment that sellers like to quote.
  • Makes the trade-off between a shorter and a longer loan visible in seconds.
  • Shows the real value of overpaying, which is often more than people expect.

Where it falls short

  • Assumes a fixed rate. If your rate is variable, your payment can change.
  • Arrangement fees, mandatory insurance and early-repayment fees aren't included unless they're in the rate you enter.
  • It can't tell you whether you should borrow at all. Check the payment fits your budget with room to spare.

How it's calculated

Formula. Monthly payment = P × r ÷ (1 − (1 + r)−n), where P is the amount borrowed, r the yearly rate ÷ 12 and n the number of months. At 0% it's simply P ÷ n.

Worked example. Borrowing 10,000 at 8% for 48 months: 244.13 a month and 1,718 interest in total. Paying 50 extra each month clears it in 39 months and saves 340 interest.

Assumptions.

  • Fixed rate, payment at the end of each month.
  • Fees (arrangement, insurance) are not included; compare offers by their annual percentage rate (APR), which includes most fees.
  • The last payment is adjusted by a few cents for rounding, as lenders do.

Formula checked 2026-10-23 and covered by automated tests. See the editorial policy and methodology.

Why early payments are mostly interest

Each month the lender first charges interest on what you still owe; the rest of your payment reduces the loan. At the start you owe the most, so most of the payment is interest. As the balance falls, more of each payment goes to the loan itself. That's why the schedule shows big interest numbers in year one and small ones at the end, and why overpaying early saves the most.

Comparing loan offers

  • Compare the APR, not the advertised rate. In the EU, consumer credit offers must show the annual percentage rate of charge, which includes most fees.
  • Compare the total amount payable. A lower monthly payment over a longer term usually costs more in total.
  • Check variable or fixed. A variable rate can rise; make sure the payment would still fit if it did.
  • Read the early-repayment rules. Some contracts charge a fee for paying off early, which changes the value of overpaying.
  • Watch for add-ons. Payment protection insurance or account requirements can be bundled in; ask what's mandatory.

Before you sign

Put the payment into your household budget under debt payments and see what's left. If it only fits when nothing goes wrong, it doesn't fit. Most people regret loans for things that lose value quickly far more than loans they took with a clear plan to repay.

Questions

What's the difference between the interest rate and the APR?
The interest rate is the price of the money itself. The APR adds most fees and charges and expresses the total as a yearly %, so you can compare offers fairly.
Is it better to borrow for longer to keep payments low?
Only if you need the lower payment to stay safe. A longer term almost always means more interest in total; the table shows exactly how much.
Should I overpay a loan or save?
First make sure you have a cushion. After that, overpaying an expensive loan is a guaranteed return equal to its rate; for cheap loans, saving or investing may be better.

Sources · last checked

Formula: see "How it's calculated" above; tested against the worked example shown there.

Last reviewed

Education, not advice. I'm not a financial adviser and I don't know your situation. These tools show the maths behind common rules of thumb; check important decisions with a qualified professional. Full disclaimer.