---
title: "Remortgage Calculator: What Happens When My Fix Ends?"
description: "See how much your monthly mortgage payment changes when your fixed rate ends and you move to a new rate, and what a longer term would do."
url: https://housemaths.com/tools/remortgage-calculator/
publisher: House Maths (https://housemaths.com)
editor: Daniil Shumko
note: General information about UK property, not financial advice. Check the dated figures against the sources listed.
---

# Fixed rate ending? Remortgage calculator

Enter what you still owe, the years left and your old and new rates. You'll see the change in your monthly payment, a year's difference, and the effect of a longer term.

Rates checked 3 November 2026 Checked by [Daniil Shumko](https://housemaths.com/about/#editor), editor

> **Interactive calculator.** Use it at https://housemaths.com/tools/remortgage-calculator/. The figures below are its worked example with the default inputs.

Change in your monthly payment

**+£311**

From £835 to £1,146 a month: £3,732 more a year.

Payment now**£835**

Payment at the new rate**£1,146**

New rate, 5 years longer term**£1,035**

A longer term lowers the monthly payment but means paying interest for longer. Compare the total cost, and any arrangement fees, before you choose. This is arithmetic, not advice on which deal to take.

## How it's worked out

Your payment is recalculated on what you still owe, over the years you have left, at each rate, using the standard repayment formula. The difference between the two is what the new rate costs you each month. Bank Rate rose to 4% on 5 November 2026, and fixed rates had already moved up ahead of it.

This doesn't include arrangement or valuation fees, early repayment charges if you leave a deal early, or overpayments. It isn't a mortgage offer or advice, and we don't recommend lenders.

## Common questions

### How much will my mortgage go up when my fix ends?

It depends on what you still owe, the years left and the gap between your old and new rates. On £180,000 over 22 years, moving from 1.9% to 5.2% adds about £311 a month.

### When should I start looking for a new deal?

Many lenders let you secure a new rate up to six months before your current deal ends. If you do nothing, you usually move to the lender's standard variable rate, which is often higher.

### Why did mortgage rates rise when Bank Rate only went up a little?

Fixed rates follow what markets expect rates to do over the fixed period, not just today's Bank Rate. The Bank of England noted that benchmark two-year mortgage rates had risen by nearly 0.5 percentage points between early September and November 2026.

## Sources

1.  [Bank of England: Monetary Policy Summary, November 2026](https://www.bankofengland.co.uk/monetary-policy-summary-and-minutes/2026/november-2026)
2.  [Rightmove: current UK mortgage rates](https://www.rightmove.co.uk/news/articles/property-news/current-uk-mortgage-rates/)

This calculator gives a general figure, not tax, legal or financial advice. Where the government publishes worked examples, we test it against them. Found a problem? [Tell us](mailto:support@housemaths.com).

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