Section 13 rent increase notices: what they cost, how the timeline works, and what voids them

If you have gone looking for a section 13 rent increase notice — the form, the price, the template — the short answer is that the notice itself costs nothing. The prescribed form, Form 4A, is a free download from GOV.UK. What a section 13 notice can cost you is time: get the dates wrong and you don't get a fine, you get a void notice, a restart, and two more months on the old rent. That is the part almost nobody puts a number on, so this guide does.

TL;DR

Landlords in England must now increase rent on an assured periodic tenancy by serving Form 4A (a section 13 notice) with at least two months' notice, no more than once every 12 months, and the new rent must start at the beginning of a rent period. Form 4A is published free by the Ministry of Housing, Communities and Local Government on GOV.UK — any charge for a "section 13 template" is a charge for something the government gives away. If your tenant applies to the First-tier Tribunal before the start date, the tribunal cannot set the rent higher than the figure you proposed, and under the Renters' Rights Act 2025 the new rent generally takes effect from the tribunal's decision rather than being backdated to your notice date. So the true cost of a section 13 notice is measured in months of forgone increase, not in pounds paid for paperwork.

What does a section 13 rent increase notice cost?

A section 13 rent increase notice costs a landlord in England nothing to serve. Form 4A: Landlord's notice proposing a new rent is published on the GOV.UK assured tenancy forms page for privately rented properties and is free to download, complete and hand over. GOV.UK's own guidance for landlords on rent increases under assured periodic tenancies confirms you complete Form 4A and give it to the tenant at least two months before the increase starts.

Here is where money actually enters the picture:

The notice is free. The timeline is where the money is.

That last row is the real answer to "how much should a section 13 notice cost". Take a Manchester three-bed terrace let at £950 a month, where the market has moved to £1,025. That is £75 a month, or £900 a year. Miss the rent-period alignment and slip a month, and you have handed back £75. Serve it a week short of two months and have to start again, and you are two months down: £150 gone, on a form that cost nothing.

What is the section 13 timeline from notice to new rent?

The section 13 timeline in England runs on three separate clocks, and your proposed start date has to satisfy all of them at once. Form 4A's own guidance notes set these out as three requirements drawn from section 13(2) of the Housing Act 1988, as amended by section 6 of the Renters' Rights Act 2025.

1. Check the 12-month clock first. You cannot increase the rent in the first year of the tenancy, and a further increase cannot take effect until at least a year after the last one did. GOV.UK confirms this applies even where the previous increase happened before 1 May 2026 under Form 4 or a rent review clause.
2. Work out your market figure and write it down. The increase must be no higher than the open market rent — what you would expect if you relet the property today. Keep the comparables you used; they are your evidence if the tenant goes to the tribunal.
3. Pick a start date that is the first day of a rent period. If the tenancy runs from the 12th of the month, the new rent must start on the 12th. Not the 1st, not "from next month".
4. Count back at least two full months from that date. Serve Form 4A on or before that day, by a method the tenancy allows — in person, by post, or by email only if the tenancy agreement permits email service.
5. Do nothing else. Once served, the increase takes effect automatically on the date in the notice unless the tenant applies to the tribunal or you both agree a lower figure in writing.

Worked example: a monthly tenancy with a 12th-of-the-month rent day

Say a landlord in Lancashire lets a two-bed terrace at £780 a month. The tenancy began on 12 March 2024 and the rent last went up on 1 October 2025 under an old rent review clause. She wants £830.

• The 12-month clock: the last increase took effect on 1 October 2025, so a new increase cannot take effect before 1 October 2026.
• The rent-period rule: rent periods start on the 12th, so the candidate dates are 12 October, 12 November, and so on.
• The notice period: for a 12 October start she would have had to serve by roughly 11 August. It is 1 September. So her first realistic date is 12 November 2026, served in the first week of September.

That is the whole game. Two months' notice in practice usually means around ten to eleven weeks, because the notice period and the rent-period alignment rarely land on the same day. If you want the increase in the bank by a given quarter, work backwards from the rent day, not from today.

Do I have to use Form 4A, or will my own letter do?

Landlords in England should use Form 4A. The GOV.UK assured tenancy forms guidance is blunt about prescribed forms: use them so the notice is valid, and do not change the wording unless the form says you may. Shelter England's guidance notes that a landlord can give a letter containing the same information, but that is a fine judgement to make about your own paperwork when the downside is a void notice and a two-month restart. The prescribed form is free, it contains the guidance notes your tenant needs, and it removes the argument entirely.

The practical tip: the form asks for the current rent, the proposed rent, the start date, and any bills or service charges included in the rent — split out as "nil" or an amount. Fill those charge columns in properly. A blank table is one of the easier things for a tenant's adviser to pick at.

Our guide to calculating a defensible rent increase walks through how to evidence the market figure before you commit it to the form, and how much a landlord can increase rent covers the open-market-rent test in more depth.

What happens if the tenant challenges the section 13 notice?

If a tenant applies to the First-tier Tribunal before the start date in the notice, the tribunal decides what the open market rent should be. Two changes under the Renters' Rights Act 2025 matter enormously to your cash flow:

Read those two rows together and the incentive is obvious: a tenant who thinks the increase is above market has nothing to lose by applying, and every month the tribunal takes is a month at the old rent. The GOV.UK Guide to the Renters' Rights Act also gives the tribunal power to defer an increase by up to a further two months in cases of undue hardship.

This is not a reason to avoid increasing rent. It is a reason to propose a figure you can actually evidence, rather than an optimistic one you expect to negotiate down. A £30 stretch you cannot support with comparables can cost you far more than £30 a month in delay. If a challenge does land, our guide on preparing for a First-tier Tribunal rent increase hearing sets out what evidence carries weight.

What voids a section 13 notice?

The most common ways landlords in England invalidate a section 13 rent increase notice are all date and detail errors, not disputes about the amount:

• Giving less than two months' notice.
• A start date that is not the first day of a rent period.
• Serving within 12 months of the last increase taking effect, or in the first year of the tenancy.
• Serving by email where the tenancy agreement does not permit email service.
• Relying on a rent review clause instead of Form 4A.
• Joint landlords where not every landlord has signed (or authorised one to sign).

A tenant can ask the tribunal to rule on whether the notice is valid — the Renters' Rights Act 2025 expressly gives the tribunal that power. If it is not valid, the rent does not go up and you serve a fresh notice. Diary the 12-month anniversary of every increase across your portfolio alongside your CP12 and EICR dates; the section 13 clock is now just another compliance deadline. Our wider guide to rent increases under the Renters' Rights Act covers how this fits with the rest of the new regime.

If your tenancy is unusual — a company let, an assured agricultural occupancy, a succession tenancy, or anything with a mid-conversion notice already served — take advice from a solicitor rather than guessing at the form.

Frequently Asked Questions

How much does a section 13 notice cost a landlord?

Nothing. Form 4A is a free download from GOV.UK, and there is no fee to serve it on your tenant. Your only unavoidable outlay is postage if you post it rather than hand it over.

Can I use my own letter instead of Form 4A?

GOV.UK guidance tells landlords in England to complete Form 4A and warns against altering the wording of prescribed forms. Shelter England notes a letter with the same information can be used, but the prescribed form is free and removes any argument about validity, so it is the safer route.

How much notice must I give for a rent increase in 2026?

At least two months, and the new rent must start at the beginning of a rent period. In practice that usually means ten to eleven weeks between serving Form 4A and the money changing, because the two clocks rarely align on the same day.

Can the First-tier Tribunal set the rent higher than I proposed?

No. The GOV.UK Guide to the Renters' Rights Act confirms that tenants never pay more than the landlord asked for, so the figure on your Form 4A is now a ceiling rather than an opening bid.

Can I increase the rent twice in a year if my tenant agrees?

No. GOV.UK guidance is clear that you can only increase the rent once a year and must follow the section 13 process every time, even where you have already agreed the increase with your tenant. A mutually agreed second increase inside 12 months is not enforceable through section 13.