Even a small difference in your mortgage interest rate can cost or save you tens of thousands of pounds over the life of a loan. In this guide, we’ll show you exactly how to compare mortgage rates correctly, what to look for beyond the headline figure, and how to use real numbers to make the best decision for your situation.
Why the Headline Rate Isn’t Enough
Most people compare mortgages by headline rate alone — but this is a mistake. A mortgage with a 4.1% rate and a £2,000 arrangement fee might cost more over two years than a 4.3% rate with no fee, depending on your loan size. The only accurate way to compare is to calculate the total cost over the full deal period, including all fees.
This is why our mortgage calculator is so useful — enter both deals with their respective rates and fees, and compare total costs side by side before committing.
How a 1% Rate Difference Affects Your Mortgage
The impact of seemingly small rate differences is genuinely significant over a 25-year mortgage. Here’s how a 1% difference plays out on different loan sizes:
| Loan Amount | Rate 4% | Rate 5% | Extra Monthly Cost | Extra Total Cost (25yr) |
|---|---|---|---|---|
| £150,000 | £791/month | £877/month | +£86/month | +£25,800 |
| £200,000 | £1,056/month | £1,169/month | +£113/month | +£33,900 |
| £250,000 | £1,319/month | £1,462/month | +£143/month | +£42,900 |
| £300,000 | £1,583/month | £1,754/month | +£171/month | +£51,300 |
| £400,000 | £2,111/month | £2,338/month | +£227/month | +£68,100 |
On a £300,000 mortgage, a single percentage point difference in rate costs over £51,000 more across a 25-year term — more than the annual salary of many UK workers.
Fixed vs Tracker Mortgages — Which Is Right Now?
Whether to fix or track depends on where interest rates are expected to go. In a rising rate environment, fixing is safer. In a falling rate environment, trackers let you benefit from cuts without waiting for your deal to expire.
| Mortgage Type | Rate Type | Benefit When | Risk When |
|---|---|---|---|
| 2-Year Fixed | Fixed | Rates rise | Rates fall sharply |
| 5-Year Fixed | Fixed | Rates stay high or rise | Rates fall significantly |
| Tracker | Follows base rate | Rates fall | Rates rise |
| Standard Variable (SVR) | Variable (lender sets) | Flexible exit | Usually most expensive |
| Discount | SVR minus % | SVR drops | SVR rises |
2-Year vs 5-Year Fixed: Which Should You Choose?
This is one of the most common questions for existing homeowners remortgaging. Here’s how to think about it:
Choose a 2-year fix if: You expect rates to fall in the next 2–3 years and want to be free to remortgage sooner. You’re planning to move home in the next few years. You’re comfortable with the uncertainty of your next deal not yet being known.
Choose a 5-year fix if: You want payment certainty for longer. You’re risk-averse and don’t want to think about remortgaging for a while. You believe rates will stay elevated or increase further.
Currently in 2025, 5-year fixes are priced very similarly to 2-year fixes — making the 5-year deal attractive for those who value stability. Use our mortgage calculator to compare both options with your actual numbers.
How to Get the Best Mortgage Rate
- Improve your credit score — Pay all bills on time, reduce credit card balances below 30% of limits, and avoid applying for new credit in the 3–6 months before applying
- Increase your deposit — Moving from 10% to 15% or 25% deposit can significantly drop the rate you’re offered
- Use a whole-of-market broker — Brokers access deals unavailable direct to consumers and can advise on which lenders to target based on your profile
- Check your eligibility first — A soft search (mortgage in principle) doesn’t affect your credit score; multiple hard searches in a short window can
- Don’t focus only on rate — A slightly higher rate with lower fees and flexible overpayment terms may save more money overall
Mortgage Rate Comparison FAQ
How often should I remortgage?
You should remortgage whenever your current deal ends — typically every 2 or 5 years depending on your fix period. When your deal ends, you’ll roll onto the lender’s Standard Variable Rate (SVR), which is almost always significantly higher. Start looking for a new deal 3–6 months before your current one expires to avoid a gap on the SVR.
Can I overpay my mortgage to reduce interest?
Yes — most fixed-rate mortgages allow overpayments of up to 10% of the outstanding balance per year without an early repayment charge. Even modest overpayments can save thousands in interest and shorten your mortgage term significantly. Always check your lender’s overpayment limit before paying extra.
What is a good mortgage rate in 2025?
In 2025, a competitive 5-year fixed rate for borrowers with a 20–25% deposit sits between 3.9–4.5%. For 10% deposits, expect 4.5–5.2%. Rates are highly personal — your exact rate depends on your LTV, credit score, income, and the lender’s current offers.
Does a longer mortgage term mean lower monthly payments?
Yes — but a longer term means paying far more total interest. A £200,000 mortgage at 4.5% costs £1,111/month over 25 years (total interest: £133,380) versus £879/month over 35 years (total interest: £169,192). You’d pay £35,812 more in interest for the lower monthly payment. Use our mortgage calculator to compare.
Related Calculators
- Mortgage Calculator — Compare monthly payments at different rates
- Loan Calculator — Calculate costs on personal and secured loans
- Savings Calculator — Build your deposit faster
- Percentage Calculator — Calculate LTV and rate comparisons