Mortgage Interest Rate Comparison
Compare monthly payments at different interest rates. See how rate changes affect your mortgage.
Last updated: April 2026 · Source: Bank of England - Mortgage Statistics
| Rate | Monthly | Total Interest | Total Paid |
|---|---|---|---|
| 3% | £1,185.53 | £105,658.49 | £355,658.49 |
| 3.5% | £1,251.56 | £125,467.68 | £375,467.68 |
| 4% | £1,319.59 | £145,877.63 | £395,877.63 |
| 4.5% | £1,389.58 | £166,874.36 | £416,874.36 |
| 5% | £1,461.48 | £188,442.53 | £438,442.53 |
| 5.5% | £1,535.22 | £210,565.62 | £460,565.62 |
| 6% | £1,610.75 | £233,226.05 | £483,226.05 |
| 6.5% | £1,688.02 | £256,405.37 | £506,405.37 |
| 7% | £1,766.95 | £280,084.40 | £530,084.40 |
Disclaimer
This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.
How It Works
Mortgage repayments are calculated using a standard annuity formula where the monthly payment equals the loan principal multiplied by [r(1+r)^n] / [(1+r)^n - 1], with r being the monthly interest rate and n the total number of payments. Even small rate differences produce significant cost variations over a 25 or 30-year term because interest compounds monthly on the gradually reducing balance.
The calculator compares up to four mortgage rates side by side, showing the monthly payment difference and total interest paid over the full term for each. A 0.5% rate difference on a £250,000 mortgage over 25 years typically changes the monthly payment by £60-£70 and alters total interest paid by £17,000-£20,000. This makes rate comparison essential when choosing between fixed-rate, tracker, or variable products.
UK mortgages commonly offer an initial fixed or discounted period (typically 2 or 5 years) before reverting to the lender's Standard Variable Rate (SVR). The calculator models both the initial rate period and the SVR reversion to show true total cost of ownership. Early Repayment Charges during the initial period are also factored in when comparing whether remortgaging at a new rate saves money after fees.
Comparing two fixed rates on a £280,000 mortgage over 25 years
- Rate A: 4.29% fixed for 5 years, monthly payment: £1,521
- Rate B: 4.79% fixed for 5 years, monthly payment: £1,596
- Monthly saving with Rate A: £75 per month
- Total interest over 25 years at Rate A: £176,340 vs Rate B: £198,720
- Lifetime saving choosing Rate A: £22,380 (even accounting for a £999 product fee on Rate A)
Frequently Asked Questions
- What does the Mortgage Interest Rate Comparison do?
- Compare monthly payments at different interest rates. See how rate changes affect your mortgage. All calculations are performed in your browser using official UK rates and thresholds.
- Is this based on current interest rates?
- You can enter any interest rate to model different scenarios. Check the Bank of England base rate and current mortgage deals from lenders for the latest rates.
- Should I get professional advice?
- This calculator provides estimates for guidance only. For a formal mortgage offer, speak to a mortgage broker or lender who can assess your full circumstances and provide personalised advice.