Fixed Rate vs Tracker: A Complete Mortgage Comparison
When you're choosing between a fixed rate and a tracker mortgage, you're making one of the biggest financial decisions of your life — and the difference between the two can cost or save you tens of thousands of pounds over the lifetime of your loan. A fixed-rate mortgage locks your interest rate for a set period (usually 2, 3, or 5 years), so your monthly payment stays the same no matter what the Bank of England does. A tracker mortgage moves with the base rate — if rates fall, you pay less; if they rise, you pay more. This complete guide breaks down both options with real scenarios and numbers to help you decide which fits your situation.
How Fixed-Rate Mortgages Work
A fixed-rate mortgage is exactly what it sounds like: your interest rate is frozen for a set period, typically 2, 3, 5, or 10 years. During that time, the Bank of England could cut rates to zero or raise them to 8%, and your monthly payment doesn't budge.
Example: You borrow £250,000 at 5.2% fixed for 5 years over a 25-year term. Your monthly payment is £1,484 — every single month for 60 months, no surprises. Even if the base rate rises to 7%, your payment stays at £1,484. That certainty is worth something, even if it costs a bit more upfront.
When your fixed-rate deal ends (after 2, 5, or 10 years), you remortgage. You could fix again, move to a tracker, or try a discount deal. Most people fix again because they want the certainty back. Use our mortgage calculator to work out what your fixed payment would be on your specific numbers.
Pros of fixed rates:
- Payment certainty — you know exactly what to budget for
- Protection against rising rates — if the base rate jumps, you don't feel it
- Psychological comfort — no monthly surprises
Cons of fixed rates:
- Usually more expensive than trackers when rates are falling
- You're locked in — if you want to leave the lender early, you'll pay an early repayment charge (typically 1–5% of the remaining balance)
- You can't benefit from rate cuts without paying to remortgage early
How Tracker Mortgages Work
A tracker mortgage is pegged directly to the Bank of England base rate, plus a margin set by your lender. If the base rate is 4.5% and your lender's margin is 1.5%, your rate is 6.0%. When the base rate moves, your rate moves immediately (or within a month, depending on the deal).
Example: You borrow the same £250,000 on a tracker at base rate + 1.5%. When the base rate is 4.5%, your rate is 6.0% and your monthly payment is £1,582 over 25 years. Six months later, the base rate falls to 3.5%, your rate drops to 5.0%, and your new monthly payment is £1,460. You save £122 a month automatically.
Pros of tracker mortgages:
- You benefit immediately when rates fall — the savings hit your account straight away
- Usually cheaper than fixed rates (lower headline rate)
- No early repayment charges on most trackers — you can remortgage whenever you want
- Transparent — the rate is always base rate + a fixed margin, no guessing
Cons of tracker mortgages:
- Your payment rises when the base rate rises — potentially painfully
- No payment certainty — budgeting is harder when you don't know next month's bill
- If rates keep rising, your costs can spiral quickly
Fixed vs Tracker: Side-by-Side Comparison
Here's where the numbers get interesting. Over 5 years, which actually costs more? Let's model two realistic scenarios.
Assumptions:
- Loan: £250,000
- Term: 25 years
- Fixed rate: 5.2% fixed
- Tracker: base rate + 1.5% margin
Scenario 1: Rates stay flat or fall slightly
| Year | Base Rate | Tracker Rate | Tracker Payment | Fixed Payment | Monthly Difference |
|---|---|---|---|---|---|
| 1 | 5.0% | 6.5% | £1,615 | £1,484 | Fixed saves £131 |
| 2 | 4.5% | 6.0% | £1,485 | £1,484 | Tracker saves £1 |
| 3–5 | 4.0%–3.5% | 5.5%–5.0% | £1,380–£1,460 | £1,484 | Tracker saves £24–£104 |
Over 60 months: fixed costs £89,040; tracker costs £85,200. Tracker wins by £3,840.
Scenario 2: Rates rise sharply (as they did 2021–2023)
| Year | Base Rate | Tracker Rate | Tracker Payment | Fixed Payment | Monthly Difference |
|---|---|---|---|---|---|
| 1 | 5.0% | 6.5% | £1,615 | £1,484 | Fixed saves £131 |
| 2 | 6.0% | 7.5% | £1,722 | £1,484 | Fixed saves £238 |
| 3–5 | 6.5%–5.5% | 8.0%–7.0% | £1,788–£1,650 | £1,484 | Fixed saves £166–£304 |
Over 60 months: fixed costs £89,040; tracker costs £96,720. Fixed wins by £7,680 — and that's before considering the stress of your payment rising by £300+ a month.
The maths is clear: tracker is cheaper when rates fall, fixed is cheaper when rates rise. The trick is predicting which way they'll go — and nobody consistently gets that right. Compare different mortgage term lengths with our calculator to see how payment period affects your total cost.
Real Scenarios: When Each Makes Sense
Fixed is better if:
- You're already stretched on your budget and need certainty — the peace of mind is worth the extra cost
- You believe rates will rise (no prizes for predictions, but worth thinking through)
- You're in the early years of your mortgage — stability matters when you're still adjusting to homeownership
- Your household income isn't rising predictably — you can't rely on earning more to cover rate rises
- You have a mortgage payment that's already close to your maximum affordability limit
Tracker is better if:
- You have a cash buffer (3–6 months of expenses) to cover rate rises without panicking
- You believe rates will fall or stay low — and you're comfortable with that bet
- You can afford to absorb a 2–3 percentage point rate rise without cutting into savings or essentials
- You plan to overpay when rates are low and payments are cheaper — this compounds your saving
- You're early in a longer mortgage and expect your income to rise
Read about repayment vs interest-only mortgages to understand how payment structure interacts with your rate choice.
The Impact of Rate Changes
This is where intuition breaks down. A 1 percentage point rise doesn't sound like much — until you see your actual payment.
On £250,000 at 25 years:
- At 5%: £1,460/month
- At 6%: £1,582/month (+£122, +8%)
- At 7%: £1,711/month (+£251, +17%)
- At 8%: £1,847/month (+£387, +27%)
If you're on a tracker and rates rise from 5% to 8%, your monthly payment jumps by £387. That's £4,644 a year more. Over 3 years of rising rates, you're easily looking at £10,000–15,000 in extra payments you didn't budget for. Fixed-rate holders don't feel that pain. It's why many people choose fixed — not because it's mathematically optimal, but because it's emotionally sustainable.
Meanwhile, if rates fall to 3%, your tracker payment drops to £1,265/month. But by then, you've probably already remortgaged into a new fixed deal anyway.
Use our mortgage calculator to model what your payment would be at different rates and see the real impact on your budget.
Remortgaging and Deal Length
Most fixed deals are 2, 3, or 5 years. Shorter deals (2 years) mean you remortgage more often, which exposes you to rising rates but lets you lock in lower rates if they fall. Longer deals (5 years) give more certainty but you might miss a rate cut.
Check our 2-year vs 5-year fix analysis to understand the trade-offs in deal length.
There's no universally "best" length — it depends on your conviction about future rates and your tolerance for uncertainty. If you believe rates will fall, a 2-year fix lets you remortgage sooner. If you believe they'll rise, a 5-year fix locks in today's rate longer. If you think they'll stay flat, you're in the rare camp of people with perfect rate predictions.
Frequently Asked Questions
Q: Can I switch from a tracker to a fixed rate, or vice versa, mid-deal? A: Yes, but you may pay an early repayment charge (typically 1–5% of the remaining balance). If you want to switch with your current lender, ask if they offer a "product switch" — it's often cheaper than full redemption. Always calculate whether the switching cost is worth the savings you'd make. Our calculator can help you model the payback period.
Q: What happens when my fixed-rate deal ends? A: You have four options: remortgage with the same lender at their standard variable rate (which you can then fix or track again); remortgage with a different lender; switch to interest-only; or continue paying down the mortgage. Most people remortgage to a new fixed deal. Start shopping 3–6 months before your deal ends so you lock in a new rate before the old one expires.
Q: If I overpay on a tracker, do I save more than on a fixed rate? A: Yes, mathematically. On a tracker, every extra £100 you pay reduces the balance that accrues interest at the (potentially rising) base rate plus margin. On a fixed rate, you also reduce the balance, but interest is charged at a lower fixed rate anyway, so the percentage saving is smaller. Overpaying works on both, but it's more powerful on a tracker.
Q: Can I afford a tracker if I'm already stretching on affordability? A: Lenders now stress-test you at a higher rate (usually base rate + 2%) to check you can afford a significant rise. If you pass that test, you can technically afford a tracker. But "can afford" isn't the same as "should take" — if you're already tight, a fixed rate removes a major source of anxiety and lets you sleep at night.
Q: Is the base rate the same as my mortgage rate? A: No. The base rate is what the Bank of England charges banks to borrow. Check the current base rate on the Bank of England website. Your mortgage rate is base rate + your lender's margin. A tracker mortgage is base rate + 1.5%, for example. That margin doesn't change, only the base rate does.
Q: What's the difference between a tracker and a discount mortgage? A: Both move with the base rate, but a discount is a percentage off the lender's standard variable rate (SVR), while a tracker is base rate + a fixed margin. Trackers are usually cheaper and more transparent.
Q: Which should I choose? A: If you can absorb rate rises without stress, trackers are mathematically cheaper over time. If you can't afford uncertainty, a fixed rate is worth the premium. There's no universally "right" answer — it depends on your income stability, cash buffer, and risk tolerance. The best choice is the one you can afford and sleep at night on.
Making Your Choice
The best way to decide is to run both scenarios with your actual numbers. Use our mortgage calculator to calculate what you'd pay at different rates on a tracker, and what you'd lock in on a fixed deal.
Ask yourself:
- What's my minimum monthly buffer after mortgage and all other expenses? (If it's under £300, fixed is safer.)
- Do I believe rates will fall, stay flat, or rise in the next 5 years?
- Can I afford a 2–3 percentage point rise without cutting into savings or essentials?
- How long do I plan to stay in this house? (Your time horizon affects which option pays off.)
A tracker is the mathematically optimal choice if rates fall or stay low. A fixed rate is the psychologically optimal choice if you can't afford the stress of uncertainty. Many people choose fixed even though trackers are cheaper, and that's completely reasonable — the best mortgage is the one you can afford and feel confident about.