How much could remortgaging save?

A 1% rate cut on a £180,000 balance saves roughly £100 a month - but the honest answer amortises both deals in full, nets off the fees, and compares over the same remaining term, which is exactly what this calculator does.

What is the remortgage term trap?

Taking a new deal over a longer term than you have left cuts the monthly payment - and can still cost thousands MORE in total interest, because you pay for more years. Always compare the new deal at your current remaining term first.

When should I start looking?

Deals can typically be secured up to six months ahead - start before your fix ends, or you roll onto the standard variable rate, usually the most expensive rate a lender offers.

Remortgage calculator: with the term trap made visible

Both deals amortised in full: the monthly change, the total interest saved net of fees, how fast the fees pay back, and a warning when a lower rate over a longer term would quietly cost you more. The same amortisation the Hundred Summers app uses. Your figures never leave your browser.

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Worked example

Computed when this page was built by the same engine that runs the calculator above, so the figures below and the live tool can never disagree. Change any input above to see your own.

Inputs
Balance	£180,000
Current deal	5.2% over 18 years
New deal	4.1% over 18 years
Fees	£1,200

Results
Monthly payment now / new	£1,285 / £1,180
Monthly saving	£105
Interest saved over the term	£21,546
Fees paid back in	12 months

The next question

Overpay the mortgage or invest? →Mortgage overpayment calculator

Or answer it with everything else: the full Hundred Summers plan connects your pay, pensions, savings, property, tax and spending year by year, and stress-tests them across 500 simulated market histories.

Read the guides

Overpay the mortgage or invest? The honest arithmetic →
Overpaying earns your mortgage rate guaranteed and tax-free; investing has to beat it after fees, tax and nerve. How to compare the two properly, including what happens after the mortgage clears early.
Your mortgage: how the payment is built, what the term costs, and what a rate change does →
Why half of every early payment is interest, what stretching the term to 35 years really costs, the interest-only trap, and how a two-point rate rise moves the monthly figure, with the arithmetic behind each.

The comparison most calculators fudge

The seductive number is the monthly saving; the honest number is total interest over the same remaining term, net of fees. Stretching the term almost always cuts the monthly cost and often adds total interest: the term trap this page flags explicitly. Fees matter more on smaller balances: a £1,200 fee against a £90,000 balance eats years of a small rate advantage, and fee-free deals at slightly higher rates often win.

Add any early repayment charge from your current deal to the fees, and check the payback period against how long you'll actually keep the new deal. The full Hundred Summers plan models the remortgage inside your whole picture on the Property tab, where the overpay-or-invest question usually follows.

Education, not advice. Affordability checks, product availability and your credit position are the lender's call, not arithmetic. For a personal recommendation speak to an FCA-regulated financial adviser; free impartial guidance is available from MoneyHelper.