Increasing a tenant's rent under the new Renters' Rights Act has changed completely. Here's how to fill out Form 4A correctly, with a worked example.
If you've been increasing rent by writing to your tenant, relying on a rent review clause, or just agreeing a new figure over text, that stopped working on 1 May 2026. Under the Renters' Rights Act 2025, the only way to increase rent on an assured tenancy is through a Section 13 notice using the new Form 4A. Rent review clauses are void. Informal agreements are unenforceable. If you increase rent any other way, the tenant can challenge it — and win.
What Changed on 1 May 2026?
Before the RRA, landlords had three routes to increase rent:
- A rent review clause in the tenancy agreement
- A mutual written agreement with the tenant
- A Section 13 notice (the formal route, rarely used)
Now, only the Section 13 route is available. And the form you need has changed from the old Form 4 to the new Form 4A.
The key rules that trip landlords up:
- No increase in the first 12 months of a tenancy — the "protection period"
- No more than one increase per 12-month period — measured from when the last increase took effect, not when it was served
- At least 2 months' notice must be given before the increase takes effect
- The effective date must fall on the first day of a rent period — if your tenant pays on the 1st, the increase can only start on a 1st
- The tenant can refer the increase to the First-tier Tribunal, which can now reduce the rent — not just cap it at the current level, as before
That last point is the big one. Under the old rules, the worst outcome of a Tribunal referral was the rent staying the same. Under the RRA, the Tribunal can set the rent lower than what the tenant currently pays. Proposing an aggressive increase is now a genuine financial risk.
Worked Example: Raising Rent from £950 to £1,050
Let's walk through a real scenario step by step.
The situation:
- Tenant: Sarah Jones
- Property: 14 Oak Lane, Leeds LS6 2AB
- Tenancy started: 1 March 2025
- Current rent: £950/month, paid on the 1st
- Last increase: none (first increase)
- You want to increase to: £1,050/month
- Today's date: 2 May 2026
Step 1 — Check eligibility
Before you even think about Form 4A, check two things:
- Has the tenancy been running for at least 12 months? Sarah moved in on 1 March 2025. Today is 2 May 2026. That's 14 months. ✓
- Has there been an increase in the last 12 months? No, this is the first increase. ✓
If either of these fails, stop. You can't serve the notice yet.
Step 2 — Calculate the earliest effective date
The increase must take effect at least 2 months after you serve the notice, and it must fall on the first day of a rent period.
- Today: 2 May 2026
- 2 months from today: 2 July 2026
- Sarah pays on the 1st of each month
- 1 July 2026 would be less than 2 full months from 2 May — so it's not valid
- The earliest valid effective date is 1 August 2026
This is where most landlords get caught. They calculate "2 months" loosely and end up with an invalid notice. The notice period must be a full 2 months — 1 July is only 1 month and 29 days from 2 May.
Step 3 — Complete Form 4A
Form 4A is the prescribed form. You can download it from GOV.UK by searching "Form 4A prescribed form for rent increase." Fill in:
- Tenant name: Sarah Jones
- Property address: 14 Oak Lane, Leeds LS6 2AB
- Current rent: £950 per month
- Proposed new rent: £1,050 per month
- Date increase takes effect: 1 August 2026
- Landlord name, address, and signature
- Date of notice: 2 May 2026
Double-check every field. If you use the old Form 4 (which was replaced on 1 May 2026), the entire notice is invalid and you have to start again.
Step 4 — Serve the notice
You need to get the completed Form 4A to Sarah. Valid methods:
- Hand it to her in person — ask for a signed receipt
- Post it — use Royal Mail Signed For so you have proof of delivery
- Email it as a PDF attachment — not a link, the actual form
Whichever method you use, keep proof of when and how it was served. If the tenant challenges the notice, you'll need to show the Tribunal that it was properly served.
Step 5 — Wait for the response
Sarah now has until the effective date (1 August 2026) to either:
- Accept the increase (or simply not respond — silence counts as acceptance)
- Refer it to the First-tier Tribunal for a determination
If she accepts, the rent increases to £1,050 on 1 August.
If she refers it to the Tribunal, they'll assess whether the increase is reasonable based on comparable market rents in the area. And here's the risk: under the RRA, they can set the rent at whatever they consider the market rate — which could be less than £950.
The Tribunal Risk: Why This Matters
Under the old rules, the worst a Tribunal could do was keep the rent at £950. Under the RRA, if the Tribunal decides the market rate for 14 Oak Lane is actually £900, Sarah's rent drops by £50/month — and you've lost money by trying to gain £100.
The practical advice: research comparable rents in your area before proposing anything. If your increase is within 5–10% of comparable properties, the Tribunal is unlikely to reduce the rent. Try jumping 20%+ without evidence, and you're inviting a fight you might lose.
Doorkeep tracks rent history per tenant and logs comparable rent data, so you can evidence your proposed increase if it's challenged.
Where to Get Form 4A
Form 4A is available on GOV.UK. Search for "Form 4A prescribed form for rent increase" or go to the Renters' Rights Act guidance page. The old Form 4 is no longer valid — using it makes the notice invalid.
How Doorkeep Helps
Doorkeep's rent increase engine handles the validation that catches most landlords out:
- 12-month protection period check — won't let you create an increase within 12 months of the tenancy start
- Cooldown enforcement — prevents more than one increase per 12-month period
- Earliest effective date calculation — factors in the 2-month notice period and aligns to the tenant's rent period start date
- Serving method and evidence logging — records the proposed increase, the date served, the method of service, and the outcome in the Evidence Vault
- Tribunal outcome tracking — if the tenant challenges, record whether the rent was upheld, reduced, or delayed
You still need to complete Form 4A itself (Doorkeep doesn't generate the PDF), but the system ensures you don't breach the timing rules — which is where most landlords get caught.
Start a Doorkeep trial for 99p and check your rent increase eligibility in the dashboard.
Common Questions
Can I still use the old Form 4? No. Form 4 was replaced by Form 4A on 1 May 2026. Using the old form makes the notice invalid — you'd have to start the entire process again.
What about rent review clauses in the tenancy agreement? They're void under the RRA. Even if your tenancy agreement has a rent review clause, it can't be used. Section 13 / Form 4A is the only route.
Can I increase rent more than once a year? No. One increase per 12-month period, measured from when the last increase took effect — not when the notice was served. If rent went up on 1 August 2026, the next increase can't take effect until 1 August 2027 at the earliest.
What if the tenant and I just agree to a new rent informally? Informal agreements are no longer enforceable for rent increases. If the tenant later disputes it, you'd have no legal basis. Always use Section 13 / Form 4A.
What if I have a fixed-term tenancy? Fixed-term ASTs were automatically converted to periodic tenancies on 1 May 2026 under the RRA. The Section 13 rules apply to all periodic tenancies.
Does this apply in Scotland, Wales, or Northern Ireland? No. The Renters' Rights Act 2025 applies to England only. Scotland, Wales, and Northern Ireland have separate housing legislation with different rent increase rules.
What if I served a Section 13 using the old Form 4 before 1 May 2026? Notices served before 1 May using the old Form 4 remain valid under the transition rules, provided they were correctly served at the time. New notices from 1 May onward must use Form 4A.
Published 2 May 2026. Based on GOV.UK guidance current at the date of publication. This is informational content, not legal advice. Always check the latest version on GOV.UK.