UK Mortgage Repayment Calculator
Working out what a mortgage actually costs month to month is harder than it looks — the monthly figure a lender quotes doesn't tell you how much of each payment goes toward interest versus paying down what you actually borrowed, or how that split shifts over a 25-plus year term.
This calculator runs the same standard annuity formula UK lenders use internally: enter the property price, deposit, interest rate, and term, and it works out the monthly payment for a repayment mortgage, or just the interest for an interest-only one, plus the full schedule showing the balance remaining after every payment.
It's the same engine as the main mortgage calculator below — this page exists because “mortgage repayment calculator” and “mortgage calculator” are searched differently, but the tool and the numbers are identical.
A useful way to read the schedule: early payments are mostly interest, and the balance barely moves for the first several years, even though the monthly payment stays flat. That flips gradually as the balance shrinks — by the final years, most of each payment is going toward the principal. Seeing that curve, rather than just the headline monthly figure, is usually the more useful number when comparing a shorter, higher-payment term against a longer, lower-payment one.
- Enter the property price and your deposit (as an amount or a percentage).
- Enter the interest rate and mortgage term in years.
- Choose repayment or interest-only to see the monthly cost, total interest, and full schedule.
- Loan amount
- £270,000.00
- Monthly payment
- £1,500.75
- Total interest
- £180,223.69
- Total repaid
- £450,223.69
Frequently asked questions
What is the difference between a repayment and an interest-only mortgage?
A repayment mortgage pays down both interest and the amount borrowed each month, reaching zero balance by the end of the term. An interest-only mortgage only pays the interest — the full amount borrowed is still owed at the end and must be repaid separately.
Does this calculator account for fees or early repayment charges?
No — it estimates the interest and repayment schedule only, based on the property price, deposit, rate, and term you enter. Arrangement fees, valuation fees, and early repayment charges vary by lender and are not included.
How is the monthly payment worked out?
Using the standard mortgage amortization formula: a fixed monthly payment calculated from the loan amount, monthly interest rate, and number of payments, such that the balance reaches exactly zero at the end of the term.