A previous Homecost analysis found that on a £270,000 mortgage at the rates currently advertised in Bank of England Bankstats Table A5.4, a 10-year fix would cost a borrower £170,972 over the decade — about £10,253 more than the same loan held on a 5-year fix that resets at exactly the same rate, but about £7,175 less than a 5-year fix that resets at +2 percentage points. That spread is the "certainty premium": the price of buying out future rate risk for the remainder of the decade.
That number, however, was computed on headline rates with zero product fees. In practice, the longest fixes available in the UK market — Habito One, April Mortgages and Perenna — typically carry product (arrangement) fees of £999 to £1,995, and shorter fixes carry their own fees that load onto a borrower's day-one cost every time they remortgage. Once fees are included, the certainty-premium arithmetic shifts in two directions at once.
The headline rate is not the borrower's day-one cost
The Bank of England's quoted-rate series (75% LTV, 5-year fix) sat at 4.32% on the most recent monthly release (series 75LTV5Y, April 2026 snapshot). Two-year and ten-year fixes are typically priced about 20bps below and 50bps above the 5-year benchmark respectively, putting indicative headline rates at roughly 4.10% and 4.85%.
Those are the rates a borrower sees in a comparison table. The number that actually leaves their account on day one is the rate plus the product fee — either paid upfront in cash or added to the loan and accruing interest at the same rate as the rest of the balance. The FCA's Mortgage Conduct of Business rules require lenders to disclose product fees alongside the headline rate, and the APRC (annual percentage rate of charge) figure on the official illustration is the closest single number to the borrower's true cost.
Fees on the three flagship long-fix products in the UK market — characterised here from each lender's publicly advertised product literature in mid-2026, and subject to change — sit in a fairly narrow band:
| Product | Typical product fee |
|---|---|
| Habito One (10–40 year fix) | ~£1,995 |
| April Mortgages (5–15 year fix) | ~£999 |
| Perenna (10–30 year fix) | ~£999 (some fee-free deals) |
Mainstream 2-year and 5-year fixes from the high-street banks typically range £999–£1,495, often advertised in two tiers ("fee-free" rate vs "fee-paid lower rate"). For the worked examples below, the 5-year base case carries a £999 fee and the 10-year £1,499 — both treated as paid in cash upfront for clarity.
Three ways to load the fee
The certainty-premium question — how much more does a borrower pay over a decade to lock a 10-year fix rather than roll 5-year fixes? — has three reasonable answers, depending on how fees are treated. All numbers below are on the same £270,000 / 30-year baseline used in the prior analysis.
1. Fee-free baseline
| Reset scenario at year 6 | 5-year strategy, decade total | 10-year strategy, decade total | 10y premium |
|---|---|---|---|
| Flat (same rate) | £160,719 | £170,972 | +£10,253 |
| +1pp | £169,219 | £170,972 | +£1,753 |
| +2pp | £178,147 | £170,972 | −£7,175 |
The 10-year fix overtakes the 5-year strategy somewhere between a +1pp and a +2pp reset — about +1.20pp on a straight-line interpolation. Below that line, 5-year-and-roll has the lower decade cost; above it, the 10-year fix does.
2. Asymmetric fees (10-year fee only)
Suppose a borrower compares a fee-paid 10-year fix at £1,499 with a fee-free 5-year fix. Adding the fee to the 10-year decade total moves it from £170,972 to £172,471 — and shifts every line of the table:
| Reset scenario | 5y total (fee-free) | 10y total (+£1,499 fee) | 10y premium |
|---|---|---|---|
| Flat | £160,719 | £172,471 | +£11,752 |
| +1pp | £169,219 | £172,471 | +£3,252 |
| +2pp | £178,147 | £172,471 | −£5,676 |
The 10-year still has the lower cost at +2pp, but by £1,499 less. The implied crossover shifts from about +1.20pp to about +1.36pp — meaning the rate would need to rise slightly further before the lock pays for itself.
3. Symmetric fees (both products pay; 5-year pays twice)
The asymmetric view flatters the 5-year strategy because it pretends the rolling 5-year borrower never pays a fee. They do — once on the original deal, and again on the year-5 remortgage. Two £999 fees over the decade total £1,998:
| Reset scenario | 5y total (+ £1,998 fees) | 10y total (+ £1,499 fee) | 10y premium |
|---|---|---|---|
| Flat | £162,717 | £172,471 | +£9,754 |
| +1pp | £171,217 | £172,471 | +£1,254 |
| +2pp | £180,145 | £172,471 | −£7,674 |
Once both strategies carry realistic fees, the certainty premium narrows at the flat scenario (from £10,253 to £9,754) but widens at +2pp (from £7,175 to £7,674). The 5-year-and-roll borrower is double-billed for arrangement fees over a decade; the 10-year borrower is not. The implied crossover moves in the opposite direction from the asymmetric case — from about +1.20pp to about +1.14pp — meaning the lock pays for itself at a slightly lower rate shock when fees are accounted for symmetrically.
The direction of the fee adjustment depends entirely on which counterfactual the borrower is comparing.
Loan size scales the headline numbers, not the fees
Monthly payments scale linearly with loan size for a given rate and term, so the decade totals scale linearly with the loan as well — but the fees do not. A £999 fee is 0.50% of a £200,000 loan and 0.25% of a £400,000 loan. The smaller the loan, the larger the fee-adjusted shift in the certainty premium relative to the underlying number:
| Loan size | Fee-free 10y premium (flat reset) | Symmetric-fee 10y premium (flat reset) | Fee impact |
|---|---|---|---|
| £200,000 | £7,594 | £7,095 | −£499 |
| £270,000 (baseline) | £10,253 | £9,754 | −£499 |
| £400,000 | £15,190 | £14,691 | −£499 |
The absolute fee impact is the same in pounds (the £1,998-vs-£1,499 net-fee gap does not depend on loan size), but it forms a much larger share of the underlying premium on a £200,000 loan than a £400,000 one. On smaller loans, fees do proportionally more of the work in the decade calculation.
What the APRC already tells you
Borrowers do not have to redo this arithmetic from scratch every time. FCA Mortgage Conduct of Business rules require lenders to disclose the APRC on the official illustration, which folds the product fee and any periodic fees into a single percentage. APRCs are required for both the initial fixed period and the overall life of the mortgage on the assumption the borrower stays with the same lender. They are imperfect — the "stays with the same lender" assumption is unrealistic for short fixes — but they remove some of the visible work in side-by-side comparisons.
The headline rate itself can be sanity-checked against the Bank of England's quoted-rate series at the BoE Quoted Household Interest Rates dashboard, and against a specific loan size and postcode using the Homecost true-cost calculator. For background on how fix length itself shifts the certainty premium before fees are layered in, see the original fix-length sensitivity analysis; and for what happens during a 10-year fix if rates fall and the borrower wants out early, see Early Repayment Charges and the falling-rate remortgage. The full set of related decade-cost analyses lives in the Cost Intelligence category.
What this analysis does not do
It does not recommend a fix length. The certainty-premium arithmetic is descriptive: at any plausible distribution of future rates, a borrower can derive an expected cost from these numbers — but the right answer depends on income certainty, the prepayment plan, the size of any emergency fund, and the borrower's tolerance for being wrong by a few thousand pounds either way. The fee tables above are computed from publicly advertised product fees in mid-2026 and from BoE Bankstats headline rates; specific lender quotes will reflect each lender's pricing on the day, the borrower's LTV band and credit profile, and any product transition discounts.
Based on 75LTV5Y BoE Bankstats quoted rates as of April 2026 and publicly advertised product fees on the major UK long-fix products. This is general information, not advice. Speak to a qualified, FCA-regulated mortgage adviser before acting.