The 12-month rule explained
Under the Renters’ Rights Act, the rent on an assured periodic tenancy can only be increased once a year. It sounds simple, but the detail catches people out: what the 12 months is measured from, how it interacts with the two months’ notice, and when the clock starts on a brand-new tenancy. This guide works through all three, with examples.
Last reviewed: 1 July 2026 · Reflects the Renters’ Rights Act 2025, in force from 1 May 2026The rule in one sentence
A new rent cannot take effect until at least 52 weeks after the last increase took effect – or, where the rent has never been increased, until at least 12 months after the tenancy began. That is the whole rule. Everything else is about measuring it correctly.
Measure from the effective date, not the service date
This is the single most common mistake. The 12-month gap runs from the date the previous increase took effect – the date the higher rent first became payable – not the date the previous notice was served. Because a Section 13 notice period is usually two to three months long, measuring from the wrong point can put your new effective date months too early, which voids the notice.
How it interacts with the two months’ notice
The 12-month gap is only one of three date rules a Section 13 notice has to satisfy. The other two are the two months’ minimum notice and the requirement that the new rent take effect on a rent due date. All three apply at once, and the binding constraint is whichever pushes the effective date latest.
- If plenty of time has passed since the last increase, the two months’ notice (rolled forward to the next rent due date) is usually what governs the earliest date.
- If you serve soon after a previous increase, the 12-month gap governs instead – and serving even earlier will not bring the date forward, because the gap is the wall you are hitting.
The Section 13 date calculator applies all three rules together and tells you which one is binding, so you can see at a glance whether it is worth serving sooner.
Worked examples
Example 1: the gap is the binding rule
Rent is due on the 1st. The last increase took effect on 1 March 2026. The landlord serves a new notice on 1 June 2026. Two months from service is 1 August – but 52 weeks from 1 March 2026 runs to 28 February 2027, so the notice rule is not the constraint. The earliest valid effective date is 1 March 2027. Serving in June was lawful but did nothing to bring the date forward: the 12-month gap decides it.
Example 2: a new tenancy’s first increase
A tenancy started on 1 June 2026 with rent due on the 1st, and the rent has never gone up. The first increase cannot take effect before 1 June 2027 – 12 months after the tenancy began – however early the notice is served. To hit 1 June 2027 exactly, the landlord must serve Form 4A on or before 1 April 2027, so that the two months’ notice is also satisfied.
Example 3: the notice rule is the binding rule
Rent is due on the 10th and the last increase took effect well over a year ago, on 10 January 2026. The landlord serves a notice on 15 August 2027. The 12-month gap was cleared long ago, so the two months’ notice governs: two months from 15 August is 15 October, which rolls forward to the next 10th – 10 November 2027.
Why the once-a-year limit exists
The 12-month rule gives tenants predictability: the rent can rise, but not more than once in any year, and always with at least two months’ notice through the Section 13 procedure. For landlords, the discipline is to plan ahead – know the earliest date you can next increase the rent, diarise it, and serve a correctly dated Form 4A when the window opens. For the full process, see how to serve a Section 13 rent increase, and to avoid the errors that void notices, read what makes a Section 13 notice invalid.
Frequently asked questions
How often can rent be increased?
Once every 12 months. The new rent cannot take effect until at least 52 weeks after the previous increase took effect, or 12 months after the tenancy started if the rent has never been increased.
Is the gap measured from the notice date or the increase date?
From the date the previous increase took effect, not the date the previous notice was served. Measuring from the service date is a common mistake that voids the notice.
When can a landlord increase the rent for the first time?
A first increase cannot take effect until at least 12 months after the tenancy began. The two months’ notice and rent due date rules still apply on top.
Can serving the notice earlier bring the increase forward?
No, not when the 12-month gap is the binding constraint. Serving early is lawful, but the effective date still cannot beat the 52-week gap or the 12-month point from the tenancy start.
Is this legal advice?
No. This page is general guidance. For advice on your situation, check GOV.UK or speak to a solicitor or professional adviser.
Disclaimer: TenancyTools.uk provides general guidance and calculation tools, not legal advice. The Section 13 rules described on this page apply to assured periodic tenancies in England under the Housing Act 1988 as amended by the Renters’ Rights Act 2025. Different rules apply in Wales, Scotland and Northern Ireland. While we work hard to keep every page accurate and up to date, you should verify dates and requirements against the current prescribed form and guidance on GOV.UK before serving or responding to a notice, and take professional advice where the outcome matters.