The four things you need, and where they are
Your outstanding balance and your years remaining are on your most recent annual mortgage statement and in your lender's app. Your current rate is the fixed rate you are on now. The date your fix ends is on your original offer document and usually in the app too. Averages are useful for understanding a market and useless for planning a household, which is why this calculator asks for your own four numbers.
Where the rates sat in September 2026
The Moneyfacts average two-year fix was 5.84% and the average five-year fix 5.88%. The best-buy two-year fix was 4.66% and the best-buy five-year 4.70%, both from Danske Bank, both up to 85% loan to value, both with a £1,124 arrangement fee. The average Standard Variable Rate was 7.13%. Those are advertised averages across every product on the shelf. The Bank of England's effective rate on mortgages actually completed in July 2026 was 4.45%, because completed loans skew towards lower loan-to-value lending where rates are cheapest. You will land somewhere between the two, and where depends almost entirely on your loan to value.
Two rules of thumb worth carrying
Every one percentage point costs roughly £60 a month for every £100,000, on a twenty-year term. Check it against the table above.
The shorter the term remaining, the less a rate rise hurts. On a short term most of each payment is capital, and capital repayment is not affected by the rate. That rule has a sting in it: extending your term lowers the payment and raises the share of it that is interest, which makes you more exposed to the next rate move, not less.
What the market did in 2026
Bank Rate has been 3.75% since 18 December 2025 and has not moved once in 2026. Over the same stretch the average two-year fix went from 4.84% in March to 5.84% in September, because swap rates climbed above 4.70%. Waiting for the Bank of England to cut was advice about the wrong number.
Before you use this
This is general information, not financial advice. It does the math on the numbers you type in. It does not know your circumstances, and it does not recommend any lender, product or course of action. Nothing you type here is stored or sent anywhere. It stays on your phone and disappears when you close the page. There is no account, no sign-up and nothing saved.
