Form 4 vs Form 4A: which rent increase form to use

The short answer

If you are a private landlord in England increasing the rent on an assured periodic tenancy, use Form 4A. Form 4 is now for the social rented sector. The switch happened on 1 May 2026, when the main changes in the Renters’ Rights Act 2025 came into force. A Form 4 notice served before that date still applies. A notice served on the wrong form since then may not be valid, so the safest fix is usually to serve a fresh Form 4A with a new start date.

This guide explains the difference between Form 4 and Form 4A, which one to use and what to do if you used the wrong one. It is general information for landlords in England, not legal advice.

Form 4 vs Form 4A: which one do you need?

Both forms are notices under section 13 of the Housing Act 1988 proposing a new rent. The gov.uk assured tenancy forms page sets out who uses which form.

Form 4A itself says, on its first page, that it is for use in the private rented sector in England only, and that tenancies in the social rented sector use Form 4.

The rule of thumb is simple. If you are a private landlord, the form you need has an “A” on the end.

What changed on 1 May 2026

Before 1 May 2026, private landlords also used Form 4 to propose a new rent. Since then, private landlords use Form 4A. The change came with wider reforms to rent increases for private assured periodic tenancies:

• Section 13 is the only route. Form 4A is the only way to increase the rent. Rent review clauses in tenancy agreements no longer work for increases that would take effect after 1 May 2026.
• Once a year. You can increase the rent no more than once a year, and not within the first 52 weeks of the tenancy.
• Two months’ notice. Serve the notice at least two months before the new rent starts.
• First day of a rent period. The new rent must start on the first day of a rent period.
• Tribunal challenge. Your tenant can refer the proposed rent to the First-tier Tribunal before the start date. The tenant will not pay more than the rent you proposed. See what happens if a tenant challenges a rent increase.

Gov.uk guidance also says you should follow the section 13 process each time, even if you have already agreed the increase with your tenants. For more on this, see rent increase letter vs Section 13 notice.

Notices served before 1 May 2026

If you used Form 4 to give notice of a rent increase before 1 May 2026, gov.uk guidance says the notice period and rent increase stated in the form still apply, even if the new rent starts after that date.

Whatever form was used, you cannot increase the rent again until at least a year after the last increase took effect. This also applies where the last increase came from a rent review clause in the tenancy agreement.

What if you used the wrong form?

Section 13 requires the notice to be in the prescribed form. For a private tenancy in England since 1 May 2026, that is Form 4A. A notice on Form 4 is a form meant for social housing, and may not be treated as valid.

The tenant can refer a notice to the First-tier Tribunal. Form 4A says a tenant can do this if they believe the rent is above the market rate, or if they believe there is another problem with the notice.

If you have served Form 4 on a private tenant since 1 May 2026, the safest course is usually:

1. Do not rely on the old notice. Do not demand the new rent from the date in it.
2. Tell the tenant. Explain in writing that you are replacing the notice.
3. Serve a new Form 4A. Work out a fresh start date that meets every rule in Note A of the form.
4. Keep proof of service. See how to serve a notice.

If the tenant has already paid the higher rent under a defective notice, take advice on how to put it right. For more detail, see what to do if a Section 13 notice was served on the wrong form.

Worked example: replacing a Form 4

A private tenancy began on 1 August 2025. Rent is £1,000 a month, due on the 1st. There has been no increase since it began.

On Thursday 1 October 2026, the landlord used an old Form 4 template saved on their computer. It proposed £1,050 a month from Sunday 1 November 2026. That notice has two problems. It is on the wrong form, and it gives only one month’s notice.

The landlord replaces it. They hand a new Form 4A to the tenant on Friday 9 October 2026.

So question 4.6 of the new Form 4A reads 1 January 2027. The tenant keeps paying £1,000 a month until then. The two-month delay compared with the original plan is the cost of the wrong form.

Our free rent increase date calculator works out this date for you. For more scenarios, see how to work out the earliest rent increase date.

How to make sure you have the right form

• Look at the title. Form 4A is headed “Landlord’s notice proposing a new rent for assured tenancies in the private rented sector”.
• Check the version. The current Form 4A on gov.uk is marked version 05.26.
• Delete old templates. Remove any Form 4 you saved before May 2026, so nobody in your business picks it up by mistake.
• Check your agent. If a letting agent serves notices for you, ask which form they use.

Our Section 13 notice page fills in Form 4A for you, based on the gov.uk form, and checks your start date before you download it.

Common mistakes

• Reusing an old Form 4. Since 1 May 2026, private landlords use Form 4A.
• Relying on a rent review clause. Section 13 is now the only route to a rent increase.
• Giving one month’s notice. The minimum is now two months.
• Starting the new rent mid-period. It must start on the first day of a rent period.
• Increasing twice in a year. Wait at least a year after the last increase took effect.
• Editing the form. Do not remove section 5 or the notes. The tenant needs them.

Frequently asked questions

Is Form 4 still valid?

Yes, for social landlords. Private landlords in England have used Form 4A since 1 May 2026.

My Form 4 notice was served in April 2026. Is it still valid?

Gov.uk guidance says a Form 4 notice given before 1 May 2026 still applies, including the notice period and increase in it, even if the new rent starts after that date.

Can the tenant challenge a Form 4A notice?

Yes. They can refer it to the First-tier Tribunal before the start date in question 4.6. They can challenge the amount, or another problem with the notice.

What is Form 5A?

It is the private sector form for proposing a new rent or licence fee for an assured agricultural occupancy. Most private landlords will not need it.

How do I fill in Form 4A?

See how to fill in Form 4A, question by question.

Next steps

• Create your notice on the Section 13 notice (Form 4A) page.
• Check the start date first with the free rent increase date calculator.
• Read how to fill in Form 4A before you serve.

If your tenant disputes the increase, speak to a solicitor; tenants can get advice from Shelter.