Form 4A: the rent increase form, explained field by field

Form 4A is the prescribed government form a landlord must use to propose a rent increase on an assured periodic tenancy in England. Its full title is “Landlord’s notice proposing a new rent for assured tenancies in the private rented sector”, and it is the form that gives legal effect to a Section 13 rent increase under the Housing Act 1988.

It came into use on 1 May 2026, when the Renters’ Rights Act 2025 came into force, replacing the old Form 4. From that date, Form 4A is the only document that can increase your rent: rent review clauses in tenancy agreements are void, and a letter or email proposing a new figure has no legal effect on its own.

The official form is free to download from GOV.UK (on the Assured tenancy forms for privately rented properties from 1 May 2026 page). It runs to several pages, including guidance notes addressed to you, the tenant. Those notes are part of the prescribed form: a landlord who serves a cut-down version without them risks invalidating the notice.

Form 4A is required for any rent increase proposed on or after 1 May 2026 on an assured periodic tenancy in England, which since that date covers almost all private tenancies (fixed-term assured shorthold tenancies were converted to periodic assured tenancies by the Act).

There is no alternative route. If your landlord wants a higher rent, one of two things must happen: they serve a valid Form 4A, or nothing changes. This is why the form deserves close reading when it arrives. It is not an opening offer or a courtesy letter; it is a legal instrument with strict requirements, and it either meets them or it does not.

If you received a notice before 1 May 2026, it should have been on the old Form 4 and the old rules apply to it. Anything served since then must be Form 4A. For the wider changes, see what the Renters’ Rights Act changed about rent increases.

Here is what a landlord must complete, and the rule sitting behind each field:

• The property address. Must identify your home accurately. A wrong or incomplete address creates doubt about what the notice applies to.
• Tenant names. Every tenant named on the tenancy agreement should be named, and the notice must be served on you. A joint tenant left off, or names that do not match the agreement, is a defect.
• The date the tenancy began. This matters because rent cannot be increased in the first 12 months of a tenancy. An error here can conceal a too-early increase.
• The date of the last rent increase, if any. Rent can only rise once in any 12-month period. This field is where that rule gets checked, so an inaccurate date is significant, not cosmetic.
• The current rent. Must state what you actually pay now. If your landlord gets this figure wrong, the arithmetic of the whole notice is in doubt.
• The proposed new rent. The figure your landlord wants. There is no cap on what can be written here, but the open-market rent is the legal ceiling if you challenge, and since 1 May 2026 the tribunal cannot go above this proposed figure.
• The date the new rent starts. The strictest field on the form. This date must be at least 2 months after the notice is served on you, must fall on the first day of a rent period, and must be at least 12 months after the last increase (or the start of the tenancy). A date that fails any one of those three tests makes the notice defective.
• Landlord or agent details and signature. Who is serving the notice, their address, and a signature and date. Missing or incomplete details here are a common defect on hastily prepared notices.

One structural point worth knowing: the prescribed form includes the tenant guidance pages explaining your right to challenge. The form is meant to be served whole. Missing pages, altered wording, or blanked-out sections all put validity in question.

Since the form changed in May 2026, defects have been common. These are the ones to look for, and each is a potential ground to challenge:

• The wrong form entirely. Old Form 4 served after 1 May 2026, a home-made “rent increase letter”, or an email. None of these can raise the rent.
• Notice period too short. The start date is less than 2 months after service. Landlords often count from the date they wrote the form, not the date you were served, and lose days in the post.
• Start date not on the first day of a rent period. If you pay on the 1st, an increase “from 15 August” is defective.
• Too soon after the last increase. Less than 12 months since the last rise, or an increase within the first year of the tenancy.
• Name and detail errors. Missing joint tenants, misspelled names that do not match the agreement, wrong property address.
• Wrong current rent. A figure that does not match what you actually pay.
• Incomplete or altered forms. Blank mandatory fields, missing guidance pages, no signature.
• Bad service. Sent to an old address, or served in a way the tenancy agreement does not allow. A notice that was not validly served did not start its own clock.

None of this makes your landlord a villain; template confusion and date arithmetic catch out professionals too. But the consequence is the same regardless of intent: a defective Form 4A does not increase your rent, and the current rent continues until a valid notice is served.

A five-minute review when the notice arrives can save you months of overpaying. Work through this list with your tenancy agreement to hand:

1. Is it actually Form 4A, with the tenant guidance pages included?
2. Are all tenants named, correctly spelled, matching the agreement?
3. Is the current rent stated correctly?
4. Is the start date at least 2 months after the day you received the notice?
5. Does the start date fall on the first day of one of your rent periods?
6. Has it been at least 12 months since your last increase (or the start of your tenancy)?
7. Was it served to the right address, in a way your agreement allows?
8. Is the proposed figure realistic against what similar homes nearby let for?

Questions 1 to 7 are validity checks; question 8 is the market check. Our free tool runs all of them in one pass and tells you plainly whether you have grounds on either front.

Do not just ignore a defective notice; deal with it on the record. Write to your landlord (email is fine if your agreement allows service that way), identify the defect specifically, and state that the notice is invalid and your current rent continues. Keep a copy.

Most landlords, shown a genuine defect, will withdraw the notice and serve a fresh one correctly. That fresh notice starts its own 2-month clock, which buys you time either way. Meanwhile keep paying your current rent in full: a defective notice is not a rent holiday, and arrears would hand your landlord a genuine problem to point at.

If your landlord insists the notice is valid and starts demanding the higher figure, protect your position: if there is any chance the notice works, apply to the tribunal before its start date so that route stays open while the validity argument runs.

A correctly completed Form 4A settles the paperwork question, not the money question. You can still challenge the amount by applying to the First-tier Tribunal (Property Chamber) on Form MR1 before the start date on the notice. The fee is £47, there is no hearing fee, and the tribunal decides the open-market rent for your home. It cannot set a figure above the one on the form, and any increase it approves is not backdated.

Our guide to the rent tribunal covers the application, the evidence that matters, and realistic timelines. And if you want the groundwork done for you, our £14.99 pack includes the market evidence and a completed application template.