Choosing between a fixed and variable rate mortgage is one of the first — and most important — decisions you'll make as a homebuyer. Get it right and you could save thousands. Get it wrong and rate rises could push your monthly payments up sharply when you can least afford it.
This guide explains both options clearly, shows the real-world numbers, and helps you decide which is right for your situation.
What Is a Fixed Rate Mortgage?
With a fixed rate mortgage, your interest rate is locked in for a set period — typically 2, 3, 5, or 10 years. During that period, your monthly payment stays exactly the same, regardless of what happens to the Bank of England base rate or general market rates.
How Fixed Rates Work
You agree a rate with your lender at the start. If the base rate rises 1%, your payments don't change. If rates drop 1%, you also miss out on the saving — but you keep your predictability. At the end of the fixed term, you revert to the lender's Standard Variable Rate (SVR) unless you remortgage.
Fixed Rate Pros and Cons
- ✅ Predictable monthly payments — easier to budget
- ✅ Protected from rate rises — no nasty surprises
- ✅ Peace of mind — especially useful if your income is tight
- ❌ Higher starting rate — typically slightly above variable rates
- ❌ Early repayment charges — penalties if you exit the deal early
- ❌ Missed savings — if rates fall, you don't benefit
What Is a Variable Rate Mortgage?
A variable rate mortgage means your interest rate can change at any time, based on market conditions or the lender's own decisions. There are three main types:
1. Tracker Mortgages
Your rate tracks the Bank of England base rate at a set margin above it. For example, "base rate + 1%". If the base rate is 5%, you pay 6%. If the base rate rises to 5.5%, you pay 6.5% — automatically. These can go up or down throughout your mortgage term.
2. Discount Rate Mortgages
You get a discount off the lender's Standard Variable Rate (SVR). So if the SVR is 7% and you have a 2% discount, you pay 5%. But if the lender raises their SVR, your rate rises too — even if the base rate hasn't moved.
3. Standard Variable Rate (SVR)
Every mortgage lender has an SVR. When your fixed or tracker deal ends, you're automatically moved onto it. SVRs are typically higher than deal rates — remortgaging when your deal ends almost always saves money.
Fixed vs Variable: Side-by-Side Comparison
| Feature | Fixed Rate | Variable / Tracker |
|---|---|---|
| Monthly payment certainty | ✅ Yes | ❌ Changes with rates |
| Starting interest rate | Usually slightly higher | Often lower initially |
| Protection from rate rises | ✅ Fully protected | ❌ Not protected |
| Benefits from rate falls | ❌ No | ✅ Yes |
| Early exit flexibility | Usually penalised | Often more flexible |
| Best when rates are... | Low (lock in the low rate) | High and expected to fall |
| Best for... | Tight budgets, first-time buyers | Risk-tolerant buyers, overpayers |
Real Numbers: How Much Could It Cost You?
On a £250,000 mortgage over 25 years:
- Fixed at 5.0%: Monthly payment = £1,461 / Total interest = £188,300
- Variable starting at 4.5%: Monthly payment starts at £1,389 / but rises if rates go up
- If variable rate rises to 6%: Payment jumps to £1,611 — £222/month more
A 1.5% rate rise adds £222/month — that's £2,664/year more. Over 5 years with sustained higher rates, that's over £13,000 extra spent versus a fixed deal.
How to Choose: A Simple Framework
Ask yourself these questions:
- Is my budget tight? → Fixed rate is safer
- Do I think rates will fall? → Tracker could be better
- Am I planning to sell or remortgage soon? → Check early repayment charges on fixed deals
- Am I a first-time buyer? → Fixed rate gives peace of mind
- Can I absorb payment increases of £200+/month? → Variable becomes viable
🎯 Verdict: Who Should Choose What?
Choose Fixed If...
You're a first-time buyer, on a tight budget, want payment certainty, rates are currently low, or you're risk-averse. 2 and 5 year fixes are the most popular choice.
Choose Variable If...
You have financial flexibility, expect rates to fall, plan to overpay heavily, want to avoid early repayment charges, or are buying a short-term property.
What About the Current Market?
Mortgage rates shift constantly based on Bank of England decisions, inflation, and lender competition. Always check current rates and speak to a whole-of-market mortgage broker who can access deals unavailable directly. Brokers are often free to use as they earn commission from lenders.
See the Numbers for Yourself
Use our mortgage calculator to compare fixed and variable rate scenarios side by side and see exactly how much difference the rate makes over your full term.
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