The ONS Price Index of Private Rents tells you how average rents have moved in a local authority, from official statistics. It cannot value an individual property. The statutory benchmark for a rent review in England is the open market rent of that property, decided by the First-tier Tribunal if the tenant challenges.

The Renters' Rights Act changed the ground rules for rent increases in England. Since it took effect on 1 May 2026, every rise on a private assured tenancy runs through a Section 13 notice on Form 4A, served at least two months ahead, which the tenant has the right to refer to the First-tier Tribunal before it takes effect.[4] That has sent agents looking for authoritative data, and the most authoritative rent data available is the ONS Price Index of Private Rents (PIPR). Used honestly, it is strong context for a proposed rent. Stretched into a valuation, it claims more than it can carry, and a well-advised tenant will notice. Here is the honest version.

What does the index get right?

PIPR is the official measure of private rent levels and inflation, published monthly and, in England, down to local-authority level.[2] The underlying data in England are achieved rents, not asking rents: Rent Officers at the Valuation Office Agency collect over 450,000 rents a year, across new, renewal, and existing tenancies.[2]

That collection basis is the defining feature. PIPR is a stock measure: it aims to reflect price changes for all private rental properties, not only those newly advertised.[2] It answers a question no portal index can: what has happened to rents across the whole market, sitting tenants included.

The August 2026 release puts the average private rent in England at £1,451 a month, up 3.8% in the 12 months to July 2026.[1] The spread matters more than the headline: the North East saw the highest regional inflation at 6.3%, the South East the lowest at 2.9%.[1] Figures update monthly, so check the current bulletin before quoting a number.

Bar chart of annual private rent inflation by English region in the 12 months to May 2026, shown as at the June 2026 release, North East highest at 5.9%, London lowest at 2.0%, England average 3.4% marked as a reference line, with rent levels England £1,442 and London £2,294 called out. ONS PIPR, June 2026 release, UK figure provisional

For a rent review, that standing is the point: the series is free, methodologically documented, and publicly checkable, so anyone can verify your working.[2] For the full definitional explainer, see what is the ONS Price Index of Private Rents.

How is the average made?

The published figures are not simple averages of the rents collected. Each property is described by its characteristics, such as bedrooms, floor area, property type, location, and furnished status, and a model estimates how much each characteristic contributes to rent.[2] Each January the ONS fixes a basket of properties from the previous year's data, then re-prices that same basket every month.[2] That mix-adjustment is what makes month-to-month comparison meaningful: a month where more one-bed flats happen to be collected does not drag the average down.

Two mechanics are worth knowing before you quote a local figure. A collected rent is assumed constant for up to 14 months if no update arrives, so part of the modelled stock reflects rents that have not been re-verified recently.[2] And below regional level the series are smoothed with a three-month moving average, because low collection volumes make some local authorities volatile.[2]

Six things the index cannot tell you

None of this makes PIPR weak. It makes it an average, and averages have limits. Six matter in a rent review.

  1. It cannot see the property. Condition, refurbishment, outside space, the EPC, the exact street: none of it is in a local-authority average. The index tracks the market around a property, never the property.
  2. It lags the new-let market. Because sitting tenancies are included, the stock average typically moves more slowly than newly advertised rents in a rising market.[2] An indexed figure is usually a conservative reference next to new-let evidence, which is defensible framing, but it is not "the market rate".
  3. It compounds whatever base it starts from. Index-linking assumes the current rent was at market when it was set. If the property was under-rented then, indexation carries that discount forward, review after review.
  4. Local authority is the floor. There is no postcode or street-level series, the City of London and the Isles of Scilly are not published at all, and one local authority can contain very different micro-markets.[2]
  5. It is a mean, not a median. Published levels are modelled means, which high-value stock can pull above the typical rent; the ONS is planning a separate median and quartile product precisely because PIPR does not provide one.[2][3]
  6. The newest months are provisional. The latest two months of UK estimates are revised monthly. Revisions are usually tiny, no more than 0.02 percentage points on the annual rate per ONS analysis, but flag provisional data when you rely on it.[2]

If an indexed figure goes in front of a landlord or a tenant, you should be able to recite these limits without looking them up.

Under the Housing Act 1988, as amended by the Renters' Rights Act, the benchmark for a challenged rent is the rent at which the property might reasonably be expected to be let in the open market by a willing landlord.[5] Government guidance for landlords puts it plainly: the rent you would expect to receive if you relet the property on the open market.[4] If the tenant refers your notice before the new rent's start date, the tribunal decides that figure.[4]

An index cannot answer that question, and no ONS publication will ever set or validate a specific rent. What speaks to the statutory test directly is evidence of what similar nearby properties actually let for; official guidance tells challenging tenants to gather exactly that.[6] The index shows the average drift around your evidence, which is why comparables carry the case and indexation supports it, not the other way round. The published tribunal record argues the same from the other direction: see what 1,000+ tribunal decisions tell agents about evidence.

Using indexation honestly in a rent review

Done properly, the method is short. Anchor to the right series: the property's local authority and, where relevant, its bedroom category.[2] Move the current rent by the index between the month the rent was last set and the latest settled month. Record the working, meaning the series, geography, months used, dataset edition, and provisional status, so the number is auditable and reproducible. Then present it as context alongside comparables, never instead of them.

Our Free Rent Indexation Tool does this from a postcode: it returns an indexed reference point and range with local-authority context, based on published ONS data. It is a starting point for framing a conversation about rent, not a market rent determination, and it covers England only. Inside MarketRent, PIPR is the default rent index, and indexation sits alongside comparables and the EPC in the evidence pack for each review. MarketRent does not tell you what rent to charge: you decide the figure, and the platform assembles the market context and comparable evidence around it.

The honest framing for landlords and tenants takes three sentences. The ONS index shows the average movement in local rents. Comparables show what similar homes actually let for. The legal test is open market rent, and only a tribunal can determine it if a tenant challenges.[5][4] Say all three, and the index becomes what it should be: context with real authority behind it, claiming nothing it cannot support.

For the statutory process end to end, from Form 4A dates to tribunal referral, see our complete guide to rent reviews under the Renters' Rights Act.

This article is general information for letting agents in England, not legal advice.

Sources

  1. ONS, Private rent and house prices, UK: June 2026 (released 17 June 2026)
  2. ONS, Price Index of Private Rents QMI (quality and methodology information)
  3. ONS, Private rental prices development plan (updated May 2026)
  4. GOV.UK, Assured periodic tenancies: a guide for landlords — rent increases
  5. Housing Act 1988, section 14, as amended (determination of rent by tribunal)
  6. GOV.UK, Apply for an open market rent determination