Best Mortgage Calculators in the UK
Find the right mortgage calculator for UK home buyers. Compare tools for payments, affordability, stamp duty, and overpayments.
Introduction
Buying a home in the UK requires navigating one of the world's most complex property markets. With the Bank of England base rate influencing mortgage rates and UK house prices averaging £285,000 nationally in 2025, having the right calculators at your fingertips can save you thousands. This guide covers the essential free tools every UK buyer should use before signing anything.
Key Calculators
- Mortgage Repayment Calculator — Uses standard amortisation to show your exact monthly payment, total interest paid, and full repayment schedule over 25 or 30 years: Try it →
- Affordability Calculator — UK lenders typically offer up to 4.5× your gross annual income. This tool shows how much you can borrow based on income and outgoings: Try it →
- Stamp Duty Calculator — Calculates your SDLT liability across UK bands: 0% up to £250k, 5% on £250k–£925k, 10% on £925k–£1.5m, 12% above. First-time buyers get relief up to £425k: Try it →
- Overpayment Savings Calculator — Shows how much interest you save and how many years you shave off by making monthly or lump-sum overpayments: Try it →
- Fixed vs Variable Comparison — Compare the total cost of a fixed-rate deal against a tracker or SVR mortgage over the same term: Try it →
UK Average House Prices by Region (2025)
| Region | Average House Price | Stamp Duty (no relief) |
|---|---|---|
| London | £525,000 | £15,250 |
| South East | £385,000 | £6,750 |
| Midlands | £255,000 | £250 |
| North of England | £190,000 | £0 |
| Scotland | £200,000 | £0 (LBTT applies) |
Tips for UK Mortgage Hunters
Always check the Bank of England base rate before fixing your mortgage — if rates look set to fall, a tracker could save money. HMRC's stamp duty guidance is updated regularly, so cross-check any calculator against the official SDLT calculator on GOV.UK. If you're a first-time buyer, the 4.5x income rule is a starting point, but some lenders go up to 5.5x for high earners. Use the overpayment calculator to model what happens if you pay an extra £100–£200 a month — the lifetime savings can be dramatic.