Remortgage Calculator UK
Compare staying on your lender's standard variable rate with switching to a new fixed deal, after fees, legal costs, cashback and any early repayment charge.
Last updated: October 2026
Your mortgage now
The rate you will pay if you do nothing, usually the lender's standard variable rate once a deal ends.
Only if you are leaving a current fixed or tracker deal early. 0 if your deal has ended.
The new deal
Many remortgage deals include a free valuation and free legal work. Enter 0 if so.
Saving over the 5-year fixed period
£28,729
Monthly payment falls by £366.32. Switching pays for its costs after 2 months.
Over the 5-year fixed period
| Stay | Switch | |
|---|---|---|
| Amount borrowed | £200,000 | £200,000 |
| Monthly payment | £1,477.98 | £1,111.66 |
| Payments made | £88,679 | £66,700 |
| of which interest | £72,144 | £42,416 |
| Upfront costs (fee, legal, ERC, less cashback) | £0 | £999 |
| Balance owed at the end | £183,465 | £175,716 |
| Total cost (payments + costs + balance) | £272,144 | £243,415 |
Payments saved, less costs
£20,980
Less owed at the end
£7,749
Break-even
2 months
How it works
The calculator works out two monthly payments on your remaining balance and remaining term: one at the rate you would pay by staying put (usually your lender's standard variable rate, the SVR) and one at the new fixed rate. Both use the standard capital-and-interest formula with interest charged monthly at the annual rate divided by 12, the same convention as our mortgage calculator.
It then follows both mortgages through the fixed period and compares the total cost: every payment you make, every upfront cost of switching, and the balance you still owe at the end. Counting the end balance matters, because a lower rate means more of each payment clears capital, and a fee added to the loan means you owe more.
Worked example. £200,000 left over 25 years. On a 7.5% SVR the payment is £1,477.98 a month. On a 4.5% five-year fix it is £1,111.66, a saving of £366.32 a month. Over five years that is £21,979 less in payments, or £20,980 after the £999 fee, and you also owe £7,749 less at the end, so you are £28,729 better off overall. The fee is recovered within 2 months.
Adding the arrangement fee to the mortgage avoids a cash outlay, but you pay interest on it for the whole term unless you overpay. In the example above, adding the £999 fee pushes the payment to £1,117.22 and leaves you £28,517 better off over five years, against £28,729 if you pay it upfront. Some lenders also charge interest on an added fee at the full rate from day one, so check the illustration.
A deal with a large fee and a low rate usually suits a large balance. On a small balance a fee-free deal at a slightly higher rate often wins. For example, with £60,000 left over 8 years, moving from 4.6% to a 4.2% two-year fix with a £999 fee leaves you £561 worse off over the two years, because the fee wipes out the saving.
Mortgage calculators
This calculator is part of a family. The main calculator covers the general case.
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Reviewed by Alexandre Bernier, LLM (UK), CFP®
Educational tool: estimates only. Not individual financial, investment, tax or legal advice. Using it does not create an adviser-client relationship. Rules and figures change; check them against current HMRC and GOV.UK guidance and speak to a qualified professional. Editorial policy →
Sources
Every rate and threshold used by this calculator is taken from the official pages below. If a figure here disagrees with one of these, the official page is right, please tell us.