Predicted
£820,000
Offrly Sale Valuation Accuracy Report (2026)
How accurate is Offrly's sale valuation? Every valuation we publish is frozen at quarter-end and, six months later, auto-joined to the actual sold price in HM Land Registry data — no admin in the loop. We publish the headline metrics and the per-property-type breakdown, the good and the bad.
Offrly's accuracy figures are tracking but not yet published: every BUY valuation we issue is frozen at quarter-end and auto-joined to the eventual HM Land Registry sold price 6 months later. The first published metrics land on 2026-12-30.
Valuations issued
293
BUY valuations logged to date
This quarter (2026Q2)
293
to be frozen on 2026-06-30
Snapshots frozen
0
0 valuations sealed for auto-join
First metrics due
2026-12-30
when HMLR catches up to 2026-06-30 sales
Illustrative example
How a single auto-joined pair will look
Once the first quarterly snapshot resolves, every pair on this page will be computed exactly like this. The numbers below are made up for illustration — no specific home is implied.
- Offrly issues a sale valuation on a flat in
SW11 4AB: predicted £820,000. - At quarter-end, the valuation row is frozen to the immutable snapshot — postcode, prediction, timestamp.
- About six months later, HM Land Registry publishes a sold record for the same postcode, dated after the valuation: actual £795,000.
- The auto-join pairs them with no human curation. The metrics below pop out automatically.
HMLR sold
£795,000
|Error|
£25,000 · 3.1%
Verdict
Hit ≤ ±10%
How we measure accuracy
Offrly's accuracy figures are computed against HM Land Registry Price Paid Data — the authoritative record of every residential property transaction in England and Wales, published monthly under the Open Government Licence.
This is a prediction-vs-outcome report rather than a synthetic back-test. Each figure traces back to a real Offrly prediction and a real HMLR sold-price row, with no admin in the loop:
- Every BUY valuation Offrly issues in a given quarter is frozen at quarter-end into an immutable snapshot — postcode, predicted price, timestamp and 95% confidence band.
- Across every quarterly snapshot we collapse to the latest BUY valuation per full postcode. A property revalued in a later quarter only contributes its most recent prediction, so the same postcode never lands in the sample twice.
- Six months later, when HM Land Registry has published the matching sold-price data, each surviving valuation is auto-joined to sales on the same full postcode with a sold date after the valuation was made.
- If a postcode has more than one matching sale, the closest-by-price sale is selected — the same tie-break rule used on the per-quarter benchmark. We document it openly rather than hiding it.
- The metrics on this page aggregate every quarterly snapshot into a single lifetime view: hit rate within ±10% and ±20%, MdAPE and MAE.
What this number means, and what it doesn't.
Hit rate within ±10% is the share of Offrly estimates that land within 10% of the actual sold price. A 60% hit rate means 6 in 10 estimates were within ±10% — comparable to where mainstream automated valuation models (the postcode-average tools most free portals run on) typically land for UK homes. The conceptual difference matters: a traditional automated valuation model gives every property on the same street roughly the same number, because it can only see beds, postcode and broad type — not what the home actually looks like. Offrly's photo-aware AI reads each comparable the way a human analyst would, paired with hyperlocal pricing that resolves at the street level rather than the postcode — so two homes on the same road that look very different get priced very differently. A valuation is still a market estimate, not a guaranteed sale price. For probate, mortgage or insurance purposes, use a RICS-qualified surveyor.
What's in the report, transparently
- Scope: sale valuations only. Rentals are not included — there's no public sold-price equivalent for rentals to pair them against.
- Ground truth: HM Land Registry Price Paid Data — every arms-length freehold and most leasehold residential sales in England and Wales.
- Licence: Open Government Licence v3.0 — reusable, citable.
- Sample: tracking from day one. 293 BUY valuations issued to date, 0 sealed across 0 quarterly snapshots. The first auto-joined pairs land on 2026-12-30. We publish the denominator so coverage stays auditable from the start.
- Leakage controls: by construction, every prediction was made strictly before its matched HMLR sold date — predictions never see future sold prices.
- Update cadence: a new snapshot freezes at each quarter-end; metrics for that snapshot land six months later as HMLR catches up. The page recomputes on every load.
How we compare to the rest of the market
Mainstream automated valuation models — the postcode-average tools most free portals run on — publish hit-rate-within-±10% figures broadly in the 60–70% band. Offrly's differentiator isn't just the point estimate, it's the model architecture: a photo-aware AI that reads each comparable the way a human analyst would, paired with hyperlocal pricing that resolves down to the street rather than the postcode. Free, no mandatory signup, with the methodology fully auditable on this page.
All accuracy claims age quickly as the market moves. As fresh HMLR data lands and new quarterly snapshots resolve, the figures here update.
For the per-quarter view of the same data, see the sealed quarterly benchmark — each individual snapshot, dated and immutable. Both pages compute their metrics from the same auto-join; this one just pools every quarter so the sample is bigger.
Frequently asked questions
What does 'hit rate within ±10%' mean?
It's the share of Offrly sale estimates that land within 10% of the actual sold price across every valuation we've matched to an HM Land Registry sale. A 60% hit rate means 6 in 10 estimates were within ±10% — an industry-standard way of measuring how close an automated valuation model gets to the true price.
How are predictions paired to HMLR sales?
Every BUY valuation issued in a given quarter is frozen to an immutable snapshot at quarter-end. Across every snapshot we collapse to the latest BUY valuation per full postcode, so a property revalued in a later quarter only contributes its most recent prediction. Six months later, when HM Land Registry has published the matching sold-price data, each surviving valuation is auto-joined to sales on the same full postcode that completed after the valuation date. There is no human review. When a postcode has more than one sale in the window, the closest-by-price sale is selected — the same rule used on the per-quarter benchmark.
Does this cover rentals?
No. The accuracy report is for sale valuations only. There is no public sold-price equivalent for rentals, so we cannot publish a comparable rental accuracy figure honestly.
How is this different from the per-quarter benchmark?
The metrics on this page aggregate every quarterly snapshot into a single lifetime view. The /benchmark URL shows a single quarter's snapshot, sealed and dated. Both pages compute their metrics with the same auto-join — this one just pools the snapshots so the sample is bigger.
Why should I trust these figures more than a marketing claim?
Because the ground truth is HM Land Registry, published under the Open Government Licence — and the pairing is fully automated, with no admin choosing which pairs make the cut. Each figure on this page traces back to a frozen Offrly prediction and the closest-by-price HMLR sold row that followed it on the same postcode.
Should I use an Offrly valuation instead of a surveyor?
No. Offrly estimates are indicative market guidance. For probate, mortgage, insurance or tax-binding figures, use a RICS-qualified surveyor. Offrly is for orientation, negotiation and informal decision-making — not for binding purposes.
Source: HM Land Registry Price Paid Data, licensed under Open Government Licence v3.0. Offrly estimates are indicative market guidance — not regulated valuations and not financial, tax or legal advice.