Data sources
The market-rent comparison is calibrated to two publicly available UK datasets, both of which are used by housing officers, tribunals and local-authority strategy teams:
- ONS Private Rental Market Statistics. Monthly UK rent index published by the Office for National Statistics. We use the regional and local authority breakdowns to anchor headline rent levels.
- VOA Private Rental Market Summary Statistics. Local-authority-level private rents data from the Valuation Office Agency, broken down by property type (room, studio, 1-bed, 2-bed, 3-bed, 4-bed+) with lower quartile, median and upper quartile. This is the closest public proxy for the open-market range a tribunal would consider for a given area.
How a single check works
When you enter a postcode, property type and bedroom count, we resolve a comparison in this order:
- Postcode prefix match. We take the first part of the postcode (e.g.
E8,SW2,M14) and look up the local-authority VOA series for that area, filtered to your property type and bedroom count. - Local-authority fallback. If we can't resolve the postcode prefix cleanly, we fall back to the local authority implied by the postcode and use its VOA summary statistics for the same property type and bedroom count.
- Regional fallback. If neither lookup returns a usable sample, we fall back to the relevant ONS regional rent for the property type. We label this on the result so you know it's a regional rather than postcode-level comparison.
The output is a three-figure range — lower quartile, median, upper quartile — for properties of your type in your area. Your proposed rent is then placed on that range and classified into one of four bands: below market, around market, at the top of the market or above market.
Update cadence
The ONS publishes the Private Rental Market Statistics monthly. The VOA refreshes its local-authority private rents publication quarterly. We pull the latest published vintage into RentCharter within a calendar week of each publication. Every result page shows the publication date of the underlying data so you can confirm how current it is.
What this is not
- Not a regression on live listings. We don't predict rent from listing features (square footage, EPC, distance to a tube station). We compare against a published distribution.
- Not a regulated valuation. The output is indicative. A formal valuation would require a RICS-registered surveyor visiting the property.
- Not a substitute for the tribunal. A First-tier Tribunal decision uses comparable evidence specific to the individual property and area. Our check is a fast first-pass that tells you whether the proposed figure is in the right ballpark.
- Not personalised legal advice. Every page is labelled “information only, not legal advice” — and we signpost to Shelter and Citizens Advice for advice on your specific situation.
Showing uncertainty
Every comparison comes with a confidence label that reflects:
- The size of the underlying VOA sample for your area and bedroom count.
- How close the proposed rent sits to the lower/upper quartile.
- Whether the lookup was postcode-prefix, local-authority or regional.
A “low confidence” label doesn't mean the result is wrong — it means the underlying public sample is thin (typically rural local authorities or rare property types). In those cases, tribunal-grade evidence usually comes from agent-supplied comparables rather than published statistics, and we say so.
What we plan to add
The roadmap is open. The current priority list:
- Tenant-submitted rents, moderated and aggregated, to fill in the gaps the published statistics don't cover.
- First-tier Tribunal outcome data so we can show, for similar challenges, what the tribunal actually decided.
- Licensed listing snapshots for cross-validation against published statistics.
- Letting agent-submitted comparable evidence, attributable and dated.
Audit and reproducibility
Every check produces an evidence pack. The pack shows the underlying comparison range, the publication date of the data, the lookup method we used, and the confidence label. If you challenge a rent to the First-tier Tribunal, that pack is what you attach — and any surveyor or tribunal member can re-derive the comparison from the same public source data.
Questions, corrections, suggestions
If you spot something wrong or you'd like to suggest a methodological improvement, write to elliot@rentcharter.org.