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How much will my mortgage go up?

Work out how much your mortgage could go up at higher rates, on a typical lender variable rate and at today’s average fixed rate.

3D glass house beside a rising glass arrow, for how much will my mortgage go up

Quick answer

How much will my mortgage go up? It depends on how much you owe, how long you have left and the rate you move to. On a £200,000 repayment mortgage over 25 years, each extra percentage point adds roughly £115 to £130 a month at today’s rates.

The calculator below shows your own figure at higher rates, at a typical lender variable rate and at today’s average 2 year fix.

Typical lender variable rate 
Average 2 year fix 
Rate pressure 
Each extra 1%About £115 to £130
On£200,000 over 25 years
Stress testIn the Theo app

Updated today

Typical lender variable rate
 
If you do nothing
Average 2 year fix
 
Across lenders
Bank Rate
 
Bank of England
Rate pressure
 
Theo’s reading
Each extra 1%
£115 to £130
A month, on £200,000
Rates tested
5
In the calculator
Stress test
2 minutes
In the Theo app
Theo reminders
5
Before your fix ends

Where rates are heading

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Reading today’s signals

Six levels, from Easing fast to Severe. Theo lights the gauge up to today’s level.

  • Easing fast
  • Easing
  • Steady
  • Building
  • High
  • Severe
Theo app rate rise stress test showing a payment now and the payment at higher rates, a typical lender variable rate and today's average 2 year fix
Example screen from the Theo app, October 2026.

How much will my mortgage go up, on my own figures?

In the Theo app, the stress test uses your own mortgage, with one tap. Premium adds what markets expect Bank Rate to be when your fix ends, and what you might pay then.

Theo’s read

Loading today’s read.

Every weekday Theo writes a plain English read of what moved in the market and what it has usually meant for fixed rates.

19 signalsUpdated through the dayPlain English

Your own figures

Use your mortgage from Theo in one tap.

How much will my mortgage go up?

Enter your mortgage. The typical lender variable rate and today’s average 2 year fix are added when Theo’s live figures load.

Your payment now
£1,112
At 4.50% over 25 years.
At 5.50%£1,228 (+£116)
At 6.50%£1,350 (+£238)
At 7.50%£1,478 (+£366)

Estimates only. Not an offer or advice.

What decides how much it goes up

Three things decide the rise: how much you owe, how many years you have left, and the gap between your current rate and the new one. The same rise in rates costs more on a bigger balance, and slightly more again when there are fewer years left, because more of each payment is interest.

On an interest only mortgage the rise is simpler and sharper: your payment moves in line with the rate. Each extra percentage point on £200,000 adds about £167 a month.

A worked example

Illustrative only. £200,000 repayment mortgage over 25 years.
RateMonthly paymentChange from 4.50%
4.50%£1,112
5.50%£1,228+£116
6.50%£1,350+£238
7.50%£1,478+£366

When your payment could go up

On a fixed rate, your payment stays the same until the deal ends. It can then go up if you move onto your lender’s standard variable rate, or if today’s deals are higher than your current rate. On a tracker or variable rate, it can go up whenever Bank Rate or your lender’s rate rises. See what happens when your fixed rate ends.

Ways people soften a rise

Securing a new deal before your current one ends avoids a spell on the variable rate. Overpaying while you are on a low rate shrinks the balance the new rate applies to, and can move you into a lower loan to value band. Some people choose a longer term to lower the monthly payment, although that means paying more interest overall. An FCA-authorised mortgage adviser can tell you which fits your circumstances.

If you are worried about keeping up with payments, speak to your lender early. Lenders must treat you fairly and can discuss options with you, and free help is available from MoneyHelper.

Common questions

How much will my mortgage go up?
It depends on what you owe, how long you have left and the new rate. On a £200,000 repayment mortgage over 25 years, each extra percentage point adds roughly £115 to £130 a month at today’s rates. Use the calculator on this page for your own figure.
How much does a 1% rise add to my mortgage?
On a £200,000 repayment mortgage over 25 years, about £115 to £130 a month at today’s rates. On an interest only mortgage of the same size, about £167 a month.
Will my mortgage go up if Bank Rate rises?
Only straight away if you are on a tracker or variable rate. A fixed rate stays the same until the deal ends, but rises in Bank Rate can push up the fixed rates on offer when you remortgage.
How much will my mortgage go up when my fix ends?
It depends on the rate you move to. If you do nothing you usually move to your lender’s variable rate, which is normally well above today’s fixed deals. The calculator shows both.
What can I do if my payment goes up too much?
Speak to your lender early. Options can include a new deal, a longer term or a temporary change, and free help is available from MoneyHelper. An FCA-authorised adviser can check what suits you.

Keep exploring

Written by Jason Foord, CeMAP-qualified mortgage adviser and Director of Verifi Mortgages Ltd (FCA No. 997175), and founder of Theo. Updated 16 October 2026. Live figures on this page update automatically.

Theo App Ltd is not authorised by the Financial Conduct Authority and does not give mortgage advice. This page is information only and is not a recommendation. Figures marked illustrative are examples, not offers. Speak to an FCA-authorised mortgage adviser about your own circumstances.

Your home may be repossessed if you do not keep up repayments on your mortgage.