Free tool · nothing stored
Should I break my fixed-rate mortgage?
Leaving a fix early means paying an early repayment charge — but if the rate you could move to is far enough below (or your current rate far enough above) the market, the saving can outrun the charge before your fix ends. There is no general answer; there is only your numbers. Put them in and the chart shows both paths racing month by month, including the exact month — if any — where breaking pulls ahead.
With these numbers, the charge and fee are never recovered before your fix ends — staying is £4,472 cheaper. The answer flips as your charge steps down or rates move.
What the calculator does
It amortises your balance twice over the months left on your fix: once at your current rate, once at the new rate with the early repayment charge and any product fee added on day one. Both lines are cumulative cost; where they cross is your breakeven. It assumes the charge is paid from savings rather than added to the loan, and it ignores tax and any difference in monthly payment you would reinvest.
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 handsomely at 3%. Run the calculator with the next step down and see how the verdict moves; the date that step lands is often the single most valuable date on your mortgage. A watch tracks those dates against the market for you and emails you when the answer flips — one payment, £7.99, until your deal ends.
Run a site or blog? This calculator is free to put on your own pages — the code adds a small "Free calculator by WatchMyMortgage" link at the bottom of the widget, and that's the only thing we ask for in return.
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 on this page 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.
Does this calculator store my numbers?
No. Everything is calculated in your browser and nothing you type is sent to a server or stored.
Figures are estimates based on the numbers you enter, using standard level-payment amortisation. Your lender's own redemption statement is the definitive figure. This is information, not financial advice; for advice on your circumstances, speak to a mortgage adviser regulated by the FCA.