Calculator
What a fall-through actually costs your agency
Most calculators multiply your fee by your fall-through rate and hand you a frightening number. That overstates it by about four times, because roughly three-quarters of collapsed sales are re-agreed. Here is the honest version, with the arithmetic shown.
Last updated 27 September 2026
- Sales that collapse
- 22.0
- a year
- Never come back
- 5.7
- of those
- Expected cost
- £20,703–£23,997
- a year
Your fee per completed sale, excluding VAT£3,231
Fees lost to sales that never complete£18,507
Progression time wasted on collapsed files£2,196–£5,490
If none of them ever came back£70,942
For comparison, a year of Completer on the Agency plan is £1,190 per branch — about 37% of the fee on a single completed sale. Stopping one permanent collapse a year covers it.
Why the headline number is wrong
The figure you usually see multiplies the full agency fee by the number of sales that collapse. Two things are wrong with it.
Most collapsed sales come back. Rightmove’s listing-level data found 23% of agreed sales in England fall through at least once, but only about 6% never complete within twelve months. So roughly three in four are re-agreed, often to a new buyer within weeks. The sale is delayed and the work is repeated, but the fee still arrives.
The fee you quote is not the fee you keep. A 1.42% sole-agency fee is quoted including VAT. The agency never keeps the VAT, so the loss is the ex-VAT figure — about 17% lower than the number on the invoice.
Put together: on an average UK sale the fee is roughly £3,880 including VAT, £3,230 without it, and the expected loss per fall-through is closer to £950–£1,100 once you weight for the three-quarters that return and add the wasted progression time.
What the calculator assumes
- Permanent losses are 26% of fall-throughs, derived from Rightmove’s 23% and 6%. This is a floor: a vendor who relists with a different agent does complete, just not for you.
- £100–£250 of wasted progression labour per collapsed file, based on 9–18 hours for a full file at £23–£28 an hour, with roughly half of that spent by the time a mid-way collapse happens.
- Defaults are UK averages. If you sell in the South East your average price and fee will both be higher — change them.
It deliberately excludes the cash-flow cost of a delayed fee, the risk of losing the instruction altogether, and the reputational cost of a vendor who tells people about it. Those are real and we have not tried to put a number on them.
Sources
Fall-through rates: Rightmove, February 2026 (23% of listings collapse at least once, 6% never complete within 12 months); TwentyCi via ValuQ, 2025 (24.4%). Average sale price: HM Land Registry / ONS UK House Price Index, July 2026. Agency fee: HomeOwners Alliance, February 2026 (1.42% including VAT, range 1.2–1.8%). Progression hours are inferred from reported caseloads of 40–80 concurrent files, not a measured time-and-motion study, and are the least certain input here.