Key takeaways
- The Bank of England's quoted five-year fix at 75% loan to value was 1.28% in September 2021 and 4.78% in August 2026, a gap of 3.50 percentage points.
- On a £200,000 balance with 20 years left, that moves a capital repayment mortgage from £945 a month to £1,296. The increase is £351.
- The pound increase hardly moves with the remaining term: £168 a month on £100,000 over 15 years, £182 over 25 years. The percentage increase runs from 28% to 47%.
- Multiplying the rate change by the balance gives £583 a month on £200,000, which overstates the real increase by £233.
- The Bank's July 2026 Financial Stability Report counts nearly 750,000 households paying under 3% whose fixes end in 2026, at an average of £170 a month more.
What a fixed rate ending in 2026 does to the monthly payment
You've had the letter, or you've counted the months, and your fixed rate is ending. The question is what the payment becomes. Here's the answer on the Bank of England's own quoted rates, before the reasons yours might land somewhere else.
In September 2021 the average quoted five-year fix at 75% loan to value was 1.28%. In August 2026 the same series stood at 4.78%. A five-year deal struck in the autumn of 2021 matures now, into a rate 3.50 percentage points higher. On a £200,000 balance with 20 years still to run, a capital repayment mortgage goes from £945 a month to £1,296. That's £351 more.
The table holds the remaining term constant in each row, because that's the comparison you actually face. You aren't restarting a 25-year mortgage. You're repricing the balance you have left over the years you have left.
| Balance | Years left | At 1.28% | At 4.78% | Increase a month | Increase |
|---|---|---|---|---|---|
| £100,000 | 15 | £611 | £779 | £168 | 28% |
| £100,000 | 20 | £472 | £648 | £175 | 37% |
| £100,000 | 25 | £390 | £572 | £182 | 47% |
| £200,000 | 15 | £1,222 | £1,559 | £337 | 28% |
| £200,000 | 20 | £945 | £1,296 | £351 | 37% |
| £200,000 | 25 | £779 | £1,144 | £364 | 47% |
| £300,000 | 15 | £1,833 | £2,338 | £505 | 28% |
| £300,000 | 20 | £1,417 | £1,944 | £526 | 37% |
| £300,000 | 25 | £1,169 | £1,716 | £546 | 47% |
Every row runs on the same two quoted rates and assumes no fees. The chart plots the fifth column, the monthly increase in pounds, across all nine combinations.
Annualised, the 20-year rows come to £2,104, £4,209 and £6,313 a year. Held for the length of a new five-year fix, they come to £10,522, £21,044 and £31,566.
Why the increase is smaller than the rate change makes it look
Most people do this the quick way. Take the rate change and multiply by the balance: 3.50% of £200,000 is £583 a month. The real increase over 20 years is £351. The shortcut overstates it by £233, and the next paragraph is where that £233 goes.
A capital repayment mortgage has two parts, and only one of them is interest. At 1.28% the £945 payment splits into roughly £213 of interest and £732 of capital. At 4.78% the £1,296 payment splits into roughly £797 of interest and £499 of capital. Interest did rise by £583, exactly as the shortcut said. The capital element fell by £233 at the same time, because a higher rate pushes more of each early payment into interest and less into the balance.
That £233 isn't a saving. The loan still clears in 20 years, so what you don't repay early you repay later. It's deferred, not avoided. The distinction matters if you're weighing whether to overpay the mortgage or invest, because the interest an overpayment saves scales with the rate you're about to pay, not the one you've been paying.
The pound increase barely moves with the term. The percentage nearly doubles.
Read down the £100,000 rows. Fifteen years left gives £168 a month more. Twenty-five years left gives £182. Ten extra years of term move the increase by £14.
Now read the last column on those same three rows: 28%, 37% and 47%. Nineteen percentage points separate the shortest term from the longest, on an increase that differs by £14 in cash.
The reason is the denominator. A long remaining term makes the starting payment small, because the capital is spread thin across many months. The extra interest is much the same in pounds either way, so it lands as a far bigger share of a small payment. Anyone judging affordability as a share of income, which is how lenders and the Bank both do it, sees a different problem from someone counting pounds out of the monthly budget. The Bank put the share of post-tax household income going to mortgage repayments at 7.5% at the end of 2025.
Two years, five years or variable, at the August 2026 quotes
The quoted two-year fix at 75% loan to value was 4.92% in August 2026 and the five-year was 4.78%. Fourteen basis points apart. On £200,000 over 20 years that's £1,311 against £1,296, a difference of £15 a month. The same quoted two-year series read 5.13% in September 2026, while mortgage rates in October 2026 on the Moneyfacts average of every fixed product on sale stood at 5.98% on 5 October.
The quoted two-year variable deal in the same band was 4.23%, which is 69 basis points below the two-year fix. On the same balance and term that's £1,236 a month, £59 below the five-year fix. A variable rate can move the month after you take it and a fix cannot, so the two are not measuring the same thing. Which of them has paid off over a long run is a separate question, and the fixed vs variable mortgage record is where it gets settled.
The loan to value band moves the number more than the term does: the five-year quote at 60% loan to value was 4.62% and the two-year quote at 90% was 5.16%, a spread of 54 basis points. That is almost four times the two-year against five-year gap. In 2026 Q2, 47.5% of gross mortgage advances were above 75% loan to value, the highest share since 2007 Q4.
What happens if the fix simply runs out
A fix that ends without a replacement reverts to the lender's variable rate. The FCA's description is that variable rate mortgages can rise at any time, because the rate is typically set by your lender and isn't directly linked to an external rate. None of the quoted series above describes that rate, and it isn't the same product as a tracker.
The Mortgage Charter is the reason most people never find out what theirs is. The FCA reports 47 signatories, representing around 90% of the mortgage market, committed to let customers lock in a new deal up to 6 months ahead of the end of a fixed rate deal. In 2026 Q2, 381,364 mortgages did exactly that, down from 499,271 in the first quarter. Remortgages for owner occupation made up 31.2% of gross advances in the same quarter, the highest since 2024 Q1, against an outstanding residential mortgage stock of £1,760.6 billion.
If the payment itself is the problem rather than the comparison, the FCA tells borrowers worried about paying their mortgage to contact their lender as soon as possible, and points them to MoneyHelper for more information on the support available. Where the balance is small against the savings you hold, the relevant comparison may not be another fix at all: an offset mortgage is priced against the savings rate you'd otherwise be earning.
Where the Bank's £170 average comes from, and why yours differs
The July 2026 Financial Stability Report puts a figure on the 2021 cohort. Nearly 750,000 households paying less than 3% are rolling off fixes during 2026, at an average repayment increase of £170 a month.
That sits close to the £100,000, 20-year line in the table, which gives £175. The closeness is two offsetting differences cancelling out, not a confirmation. The Bank's group starts anywhere below 3%, not only at 1.28%, and a starting rate near 3% produces a much smaller jump. The same group also holds balances well above £100,000, which pushes the average the other way.
The methods differ too. The Bank assumes borrowers refinance onto a fixed rate implied by the overnight index swap curve at the point their contract ends, not onto August's quoted average. For a deal ending in late 2027 those two can sit far apart, because the swap curve already prices a different rate for that date.
A fixed rate ending calculator runs the same two lines of arithmetic the table does, and inherits the same assumption: that one quoted average can stand in for the deal you'd actually be offered. A UK remortgage calculator asking only for balance, term and rate is not modelling your loan to value band, your fees, or your lender's product transfer range.
The strongest objection: most people face no jump at all
The same report makes the opposite point, and for most readers it's the more important one. For the typical owner-occupier rolling off a fixed rate in the two years from June 2026, the projected increase is £45 a month. The Bank's judgement is that most borrowers on a two-year fixed mortgage expiring by the end of 2028 remortgage close to their existing rate and see little change in repayments.
Both things hold at once. Anyone who last fixed after rates had already risen absorbed the repricing then, and the median increase between the end of 2022 and the end of 2024 was around £120. The 750,000 are what's left of the 2021 five-year cohort, and that group shrinks every month. The Bank counts a little over 5 million households seeing repayments rise by the end of 2028, against nearly 4 million in the December 2025 report. That revision came from higher market rates, not from a fresh wave of cheap fixes maturing.
So UK mortgage rates rising through 2026 hit a narrow group hard and most of the book barely at all. The average across everyone is not the number on your statement, which is the whole reason for reading it off a table rather than a headline.
What this arithmetic cannot tell you
The Bank's quoted series are, in its own words, calculated monthly as weighted averages for a range of lending and deposit products offered to households. Offered, not transacted, and averaged across lenders. No individual borrower was ever charged exactly 4.78%.
The table also ignores fees, and that is its largest limitation over a short fix. A product fee of several hundred pounds, plus valuation and legal costs where they apply, can reverse which of two rates is cheaper over two years, and the lowest headline rate often carries the largest fee. An early repayment charge on the outgoing deal works the same way in the other direction.
It assumes the balance and the term stay where they are. They often don't: around 22,400 mortgages in 2026 Q2 had monthly payments reduced by a temporary switch to interest-only payments or a term extension, which lowers the payment without touching the rate. It assumes you still qualify in the loan to value band you were in five years ago, which rests on a valuation you haven't had yet. And it cannot tell you whether your existing lender's product transfer beats the open market, because those rates never enter the quoted series.
What would change these numbers
Take the rate side first. Bank Rate stood at 3.75% after the September 2026 decision, held by a 6 to 3 vote at the meeting ending 16 September, with three members preferring 4%. CPI inflation was 3.1% in August. The UK short-term interest rate curve was upward sloping, peaking at around 4.9% by end-2027.
Fixed mortgage rates price off swaps rather than off Bank Rate directly, so the quoted five-year rate can move well ahead of any decision. The Bank's September minutes record the quoted two-year fixed rate as around 95 basis points higher than before the Middle East conflict. If that unwinds, a fixed rate ending in 2027 reprices into something below August 2026's 4.78% and every figure in the table overstates the jump. If the curve keeps climbing, they understate it.
The cohort side decides how long any of this lasts. The sub-3% five-year fixes were written in 2021 and they run out during 2026. In January 2021 the same quoted series was 1.92%, well above September's 1.28%, so even within one year the size of the jump depends on the month the deal was struck. The two-year fix at 75% loan to value was 1.20% in September 2021, and that cohort repriced three years ago. Once the last of the five-year cohort clears, the gap between the old rate and the new one closes on its own, whatever the Bank does next.