Section 13 Rent Increases, Step by Step (Form 4A)

Since 1 May 2026 there is exactly one lawful way to increase the rent on an assured tenancy: a Section 13 notice on the prescribed form — Form 4A. Rent review clauses in tenancy agreements are unenforceable, informal agreements have no effect, and a notice with the wrong dates on it is simply invalid. This guide walks the process end to end.

The four rules every valid notice satisfies

1. The prescribed form. The notice must be on Form 4A. A letter, email, or message proposing a new rent is not a Section 13 notice.
2. At least two months' notice. The new rent cannot start sooner than two months after the notice is served.
3. Once every 12 months. Rent cannot rise more than once in any 12-month period — the earliest new increase is 52 weeks after the last one (or after the tenancy started).
4. Rent-period alignment. The new rent must start on the first day of a rent period. If rent is due on the 1st, a start date of the 15th invalidates the notice.

Step by step

Step 1 — Establish your market evidence

The proposed rent should be defensible as market rent. Before you pick a number, gather comparables: similar properties, same area, currently advertised or recently let. Keep them — if the increase is challenged, this is your case.

Step 2 — Work out the earliest valid start date

Take the later of: (a) two months from service, and (b) 52 weeks from the last increase. Then roll forward to the next rent-period start day. If you're posting the notice, add at least two working days for deemed service. The calculator does all of this for you.

Step 3 — Complete and serve Form 4A

Complete the form with the current rent, proposed rent, and the start date from Step 2. Serve it the way your tenancy agreement permits, and keep proof of service — a certificate of posting, a delivery photo, or a written acknowledgement.

Step 4 — The tenant's options

The tenant can accept (pay the new rent from the start date) or refer the notice to the First-tier Tribunal before the start date. If they refer it:

• The tribunal decides what the market rent is — it can confirm or reduce your proposed rent, but cannot set it higher.
• The determined rent is not backdated: it applies from the tribunal's decision date (or the notice's start date if the decision comes earlier).
• The tribunal can defer the increase by up to two months where paying from the decision date would cause hardship.

The mistakes that invalidate notices

• Using a letter or an old form instead of Form 4A
• A start date that isn't the first day of a rent period
• Less than two months between service and the start date
• Serving within 52 weeks of the previous increase
• No proof of service when the tenant disputes receiving it

Any of these means starting again — with a fresh two-month clock.

Keep the record

Whatever happens, file: the served Form 4A, your proof of service, your comparables, and any tribunal correspondence. Under the new regime your next increase, and any future possession claim, both lean on this history being findable.

Getting it right without damaging the tenancy

The process above is the law. Whether the tenancy survives it is a separate question, and a void costs more than most increases gain.

Three things are worth doing even though none is required. Give warning before the notice arrives. A Form 4A landing unannounced reads as a demand; a short message a few weeks earlier saying a review is coming, and why, reads as management. Explain the number. "In line with similar properties locally" with two or three examples is harder to resent than a figure with no reasoning behind it. Weigh the tenant you have. A reliable tenant of four years who has never missed a payment is worth more than the last £25, and replacing them costs a void, a referencing round and an inventory.

If the tenant pushes back, stay on the process rather than the relationship: the increase is a Section 13 notice, they have the right to refer it to the First-tier Tribunal, and the tribunal decides on market rent. Saying that plainly is usually less inflammatory than negotiating, because it makes clear the number is not personal.

Sources

• gov.uk — Rent increases
• gov.uk — Private renting
• Housing Act 1988 (as amended)

Change log: 20 Aug 2026 — first published. 19 Sep 2026 — absorbed the rent-review communication guidance from how-to-review-rent-annually-the-right-way, retired the same day and now 301ing here. That article had supplied this one’s banner image since August, which was the clue the two overlapped.