Open market rent calculator
Open market rent is the yardstick the First-tier Tribunal applies when a tenant challenges a Section 13 increase. Enter your postcode, bedrooms and the rent in question to see where it sits against the local range built from ONS private rent statistics.
What the calculator is estimating
There is no formula in the legislation. Section 14 of the Housing Act 1988 asks what rent your home might reasonably be expected to fetch on the open market from a willing landlord, letting it on the same kind of tenancy. The tribunal answers that question with evidence — recent lets of similar homes nearby — and its own knowledge of the area. The calculator gives you the statistical version of the same answer: the range of rents ONS records for your bedroom count and area, so you can see at a glance whether the figure you've been given is ordinary or unusual.
What the tribunal leaves out of the calculation
Open market rent is assessed as if the property were being let fresh, with three deliberate blind spots. It ignores any improvement you paid for yourself (a new kitchen you fitted doesn't justify a higher rent to you). It ignores any disrepair you caused. And it ignores the fact that you are already living there, so a landlord can't argue for a premium because moving would be inconvenient for you. Disrepair the landlord is responsible for cuts the other way: a flat with damp or a broken boiler is not worth the open market rent of one in good order.
How to calculate it yourself, in three steps
- Collect comparables. Three to five recent lets or current listings for the same bedroom count within about a mile. Asking prices run high, so note which figures are agreed rents and which are advertised ones.
- Adjust for the obvious differences. Furnished or not, parking, outdoor space, floor level, condition. Keep a one-line note of each adjustment; that note becomes your evidence.
- Place your rent in the range. If it sits above the comparables and above the ONS range the calculator shows, you have a case worth putting to your landlord — or to the tribunal.
Common questions
Is there an official open market rent calculator on gov.uk?
No. Gov.uk explains the rules and the tribunal publishes its outcomes, but neither offers a calculator. The official input is the data: the ONS Price Index of Private Rents, which is what this calculator uses to build the local range. Everything else — comparables, adjustments for condition — is judgement, which is why the tribunal hears evidence rather than running a formula.
What does 'open market rent' mean in law?
Section 14 of the Housing Act 1988 asks what rent the property might reasonably be expected to fetch on the open market from a willing landlord under an assured tenancy. The tribunal ignores any value added by improvements you paid for and any disrepair you caused, and it ignores the fact that you are a sitting tenant. Since 1 May 2026 it can only confirm the rent in a Section 13 notice or set a lower one — never a higher one.
Is open market rent the same as the average rent?
Not quite. The average is one figure for an area; open market rent is a judgement about one property. A well-kept two-bed near the station can sit above the area average and still be at open market rent, and a tired flat on a main road can sit below it. The calculator shows a range for that reason, and the result says how closely your postcode and bedroom count were matched.
How do I calculate open market rent myself?
Three steps. Collect three to five recent lets or listings for the same bedroom count within a mile; adjust them for anything obviously different (furnished, parking, floor, condition); then place your rent in the range they describe. Our comparables guide walks through it, and the calculator gives you the statistical range to sanity-check the result against.
What can I do if my rent is above open market rent?
Negotiate first — a short, evidenced letter settles many cases. If the figure comes from a Section 13 notice you can also apply to the First-tier Tribunal on form MR1 before the new rent is due to start (£47 for notices dated from 1 May 2026; Help with Fees can reduce it). Keep paying your current rent while you wait; the tribunal's figure isn't backdated.
See also: what is open-market rent? · how to find rent comparables · rent checker by postcode · rent comparison tool.
Last updated: 1 November 2026 · Renters' Rights Act 2025 framework.
- Rent checker by postcodeYour rent against the local ONS range.
- Rent price checkerBefore you sign, at renewal, or when it feels off.
- Rent prices in your areaLocal rent levels by postcode and bedrooms.
- Rent comparison toolCompare a rent with similar homes nearby.
- How much should my rent be?Market rate and affordability, side by side.
- Fair rent calculatorWhat “fair” means in England and how yours scores.
- Is my rent too high?A quick verdict on a rent or an increase.
- Rent increase calculatorPercentage, £ and inflation modes.
- Section 13 checkerReceived a rent increase notice? Start here.
Go deeper on the market figure
The legal standard tribunals use when assessing whether a proposed rent is fair.
Read moreWhere to look, what to record and how to adjust for differences between homes.
Read moreStep-by-step through the First-tier Tribunal route, with deadlines, costs and outcomes.
Read more