Remortgage Break-Even Calculator

The decision comes down to one comparison: the interest you would save on a lower rate between now and the end of your current deal, against the early repayment charge and the fees you pay to switch. If the saving is bigger, switching early puts you ahead. If it isn't, waiting until your deal ends and remortgaging penalty-free is cheaper.

The months remaining on your deal matter more than most people expect. The same rate gap that easily covers a 1% ERC with two years to run may not cover it with four months to run, because there is simply less time for the saving to accumulate.

What is an early repayment charge?

An early repayment charge (ERC) is a charge set out in your mortgage contract for repaying all or part of the loan during the deal period. It is commonly expressed as a percentage of the balance outstanding on the day you redeem, which means the cash amount falls as you pay capital off. Not every lender uses the same structure — some products use a fixed sum, some step the percentage down each year, and some drop it entirely in the final months. Your offer document or a redemption statement is the only reliable source. To isolate the penalty on its own, use the ERC calculator.

How do I know whether paying an ERC is worthwhile?

The arithmetic is:

• interest saved on the new rate over the months left on your current deal
• minus the early repayment charge
• minus product, legal, valuation, broker and exit fees
• plus any cashback or lender contributions
• adjusted for any difference in the balance you owe at the end of the period

The last line is why simple payment-difference sums mislead. Part of every repayment-mortgage payment reduces your debt rather than being spent, so a mortgage with a lower monthly payment can leave you owing more. This calculator amortises both mortgages month by month and compares interest and cash costs, then charges any higher ending balance against the saving.

Why the lowest mortgage rate isn't always cheapest

Products with the sharpest headline rates often carry the largest arrangement fees. On a smaller balance, a fee-free product a little above the market-leading rate frequently costs less overall, because the fee is a fixed cost while the rate saving scales with how much you borrow. Run both versions through the calculator and compare the net benefit figures rather than the rates. The total mortgage cost calculator shows the same effect across a full term.

Should I add a mortgage product fee to the loan?

Adding the fee avoids an immediate cash payment, but it increases your borrowing, so you pay interest on it for as long as it stays on the balance — potentially the rest of the term. Paying it upfront is usually cheaper where you can afford to. Toggle the option in the calculator to see the difference in your own numbers.

Should I wait for my ERC to reduce?

That depends on how quickly the charge falls, the size of the rate gap, your balance and how long is left. Waiting saves ERC but costs extra interest at your current higher rate every month you delay. If your deal steps down — say 2% now and 1% in six months — enter the schedule and the calculator compares the interest cost of waiting against the ERC saved, and estimates the cheapest month to switch.

Product transfer vs remortgage

A product transfer moves you to a new rate with your existing lender. It typically involves less paperwork, often no legal or valuation work, and many lenders waive the ERC on an internal switch — though this is not universal. A remortgage moves you to a different lender, which can access a wider range of rates but usually brings more fees and a full affordability assessment. Neither is automatically better; the comparison option in the calculator scores both against staying put. If your circumstances have changed, check the mortgage affordability calculator before assuming a new lender will lend the same amount.

Timing your application

You do not have to wait until the day your deal ends to arrange the next one. Mortgage offers are usually valid for a period, so many borrowers line up a new deal in advance and complete when the old one expires. Validity periods and lender processes vary, so this calculator estimates the economics of when the old mortgage is actually redeemed rather than assuming a fixed application window.