What is a variable-rate mortgage?
A variable-rate mortgage charges an interest rate that can change over time, meaning your monthly payment can go up or down during the deal, unlike a fixed rate which stays constant.
The rate typically moves in line with the Bank of England base rate or is set at the lender's discretion, depending on the specific type of variable deal you choose.
Variable deals can offer lower initial rates than fixes, but bring less certainty over what you'll be paying in a year or two's time.
How does a variable-rate mortgage work?
With a tracker mortgage, the rate is set at a fixed margin above the Bank of England base rate and moves automatically whenever the base rate changes.
With a discount variable mortgage, you get a set discount off the lender's standard variable rate, which the lender can adjust independently of the base rate, giving slightly less predictability.
Here's a fictional example:
Meet Tom, choosing a tracker mortgage
Tom takes a two-year tracker at base rate plus 0.75%, starting at 5.25% when the base rate is 4.5%, on a £200,000 mortgage.
Six months later the base rate falls by 0.5%, so his rate drops to 4.75% and his monthly payment falls by around £58 without him doing anything.
He accepts that if the base rate rises instead, his payments would increase by a similar amount, and keeps a small savings buffer in case that happens.
What types of variable-rate mortgage are there?
Tracker mortgage
Moves directly with the Bank of England base rate plus a fixed margin, so changes are transparent and predictable in direction.
Payments rise and fall automatically whenever the base rate changes.
Discount variable mortgage
A discount off the lender's own standard variable rate, which the lender can change independently of the base rate.
Slightly less transparent than a tracker, since the lender controls the underlying rate.
Standard variable rate (SVR)
The lender's default rate, charged automatically once an initial deal period ends.
Usually the most expensive option, so most borrowers remortgage before reaching it.
Capped rate mortgage
A variable rate with an upper limit (a cap) beyond which it cannot rise, offering a middle ground between a tracker and a fix.
Less common in the current UK market, but worth asking a broker about if you want partial protection.
Is a variable-rate mortgage right for me?
Variable deals tend to suit borrowers who:
- 1
Can absorb payment changes
You need enough of a financial buffer to cope if your payment rises unexpectedly.
- 2
Expect rates to fall
A tracker lets you benefit immediately if the Bank of England cuts the base rate.
- 3
Want flexibility to exit
Many tracker deals come with lower or no early repayment charges compared with fixes.
What do I need for a variable-rate mortgage?
Lenders assess these deals similarly to fixed rates, checking:
Affordability at a stressed rate: Lenders test whether you could still afford the mortgage if rates rose significantly, not just at today's rate.
Deposit size: From 5% upward, with lower loan-to-value bands unlocking better margins above the base rate.
Credit history: A clean file opens up more lenders and tighter margins above the base rate or SVR.
Income and existing commitments: Assessed to confirm the mortgage remains affordable even if payments increase.
A financial buffer: While not always a formal requirement, lenders and brokers will encourage a savings cushion given the payment can rise.
How to compare variable-rate mortgages
Look past the headline rate and check these five things:
- 1
Initial rate vs the follow-on rate
A cheap two-year fix can revert to a lender's standard variable rate of 7% or more once it ends, so know the exit point before you sign.
- 2
Fees, not just the rate
A lower rate with a £1,999 product fee can cost more overall than a slightly higher fee-free deal, especially on smaller loans.
- 3
Overall cost over the deal period
Compare the true cost of the initial period — rate, fees and any cashback combined — rather than the rate in isolation.
- 4
Early repayment charges
Fixed and tracker deals typically lock you in with charges of 1-5% of the balance if you remortgage or overpay heavily before the term ends.
- 5
Flexibility
Look for free overpayment allowances (usually 10% a year), porting rights if you move home, and payment holiday options.
Variable-rate mortgage pros and cons
Pros
- Can offer a lower starting rate than a fix
- Payments fall automatically if rates drop
- Often lower or no early repayment charges
- Useful if you expect to move or remortgage soon
Cons
- Payments can rise with little notice
- Budgeting is harder without a fixed payment
- Discount deals depend on the lender's own SVR decisions
- Can be stressful for borrowers with tight monthly margins
Variable rate or fixed rate — which is better?
A variable rate can be cheaper when interest rates are expected to fall, letting you benefit immediately without needing to remortgage.
A fixed rate is generally the safer choice for anyone on a tight budget, since it removes the risk of payment shocks entirely during the term.
Many borrowers hedge by choosing a shorter fix rather than a full variable deal, getting some certainty while still being able to reassess the market again soon.
What happens if I can't keep up mortgage repayments?
Missing payments on a variable-rate mortgage is reported to credit reference agencies and can ultimately put your home at risk, since the property is used as security for the loan.
Contact your lender as soon as you think you'll struggle. Under FCA rules, lenders must treat customers in financial difficulty fairly and can often offer a temporary reduced payment, a term extension or a short payment holiday.
Free, independent guidance is available from MoneyHelper and Citizens Advice, and speaking to your lender early keeps far more options on the table than waiting until arrears build up.
What are the alternatives to a variable rate?
If the uncertainty doesn't suit you, consider:
Fixed-rate mortgage
Locks your payment for a set period, removing the risk of rate rises entirely during the term.
Capped-rate mortgage
A variable rate with a ceiling, offering some of the upside of a tracker with a limit on the downside.
Offset mortgage
Reduces the interest charged using your savings, which can soften the impact of rate changes.
FAQs
About this guide
Written and reviewed by the Grow Your Business team, and kept up to date as rates, rules and provider terms change.
Ready to compare?
Tell us about your business once and we'll match you with providers that fit — it takes a couple of minutes and costs nothing.
Compare variable-rate mortgages