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When your deal ends: leave early, or wait for the SVR?
The end of a deal costs money in two ways. If your fix is still running, leaving early means paying an early repayment charge, and a better rate can save more than the charge before the fix would have ended. If the fix has ended, each month on the standard variable rate is interest you could avoid. Choose your situation and enter your numbers.
Which is your situation?
The SVR meter runs from the day a deal ends — not from the day the lender's letter arrives. Every month on it with these numbers is £325 of interest that a locked deal would not have charged.
What the calculator does
Leaving early: it amortises your balance twice over the months left on your fix — once at your current rate, once at the new rate with the charge and any fee added on day one — and finds where the cumulative costs cross. On the SVR: it compares the interest at your SVR with the interest at the rate you could take instead, this month and over a year. Both use standard level-payment amortisation and ignore tax.
The part everyone misses: the charge is not a constant
Early repayment charges step down on fixed dates written in your mortgage offer — 5%, then 4%, then 3%. A switch that loses money at 5% can pay for itself at 3%, so the date a step lands is often the most valuable date on your mortgage. A watch tracks those dates against the market and emails you when the answer flips, until your deal ends. It is from £5.99, once.
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Frequently asked questions
How do I work out if breaking my fixed mortgage is worth it?
Add up the cost of leaving — the early repayment charge plus any new-deal fee — and compare it with the interest you would save at the new rate over the months left on your fix. If the saving passes the cost before your fix would have ended, breaking pays for itself. The calculator does this month by month.
What is a typical early repayment charge?
Usually 1% to 5% of your outstanding balance, and it normally steps down each year of the deal — for example 5% in year one, 4% in year two, and so on. The exact percentages and the dates they change are written in your mortgage offer.
Why does the answer change over time?
Three inputs move: your early repayment charge steps down on set dates, the rates you could switch to move with the market, and the months left on your fix shrink. A 'no' today can flip to a 'yes' on the day your charge steps down — which is a date, not a guess.
What is a Standard Variable Rate (SVR)?
The rate your mortgage moves to when a fixed or tracker deal ends and nothing replaces it. Each lender sets its own SVR, usually well above the fixed rates the same lender offers, and can change it at any time.
How much more expensive is the SVR than a fixed rate?
On the Bank of England's figures for 2026-08-31, the revert-to-rate mortgage rate is 6.58% against 4.92% for a quoted 2-year fix at 75% loan-to-value — a gap of 1.66 points, roughly £277 a month of extra interest on a £200,000 balance. Your lender's own SVR and the deals open to you differ; the calculator works out your figure.
Do I have to stay on the SVR until I remortgage?
No. Most lenders will let you switch to one of their own new deals (a product transfer) quickly, often without a new affordability check, and many let you arrange a new deal before your current one even ends. The SVR is a default, not a requirement.
Does my lender have to tell me before my deal ends?
Lenders write to you as the end date approaches, but the letter can arrive close to the date and it is easy to miss. The SVR applies from the day after your deal ends regardless of when you notice.
Does this calculator store my numbers?
No. Everything is calculated in your browser and nothing you type is sent to a server or stored. Your figures are held in this browser tab only, so they carry between the calculators.
Figures are estimates based on the numbers you enter. Your lender's own redemption statement is the definitive figure for a charge. This is information, not financial advice; for advice on your circumstances, speak to a mortgage adviser regulated by the FCA.