Rent Increase Letter vs Section 13 Notice: Which Do You Need?

If you are weighing up a rent increase letter against a formal Section 13 notice, the honest answer for England landlords in 2026 is that the two are not interchangeable, and getting the choice wrong can cost you the entire increase. Since the Renters’ Rights Act 2025 came into force on 1 May 2026, the rules on how, when and how often you can raise the rent have tightened considerably. A friendly letter still has its place, but it can no longer do the heavy legal lifting on its own. This guide explains exactly when a plain letter is appropriate, when only the prescribed statutory form will do, and how to combine the two so your increase actually sticks.

The short answer

For an assured periodic tenancy in England, which, post-Renters’ Rights Act, is now every assured tenancy, there is only one legally binding route to raise the rent without the tenant’s express agreement: serving the current prescribed Section 13 form on GOV.UK. A “rent increase letter” written in your own words has no statutory force unless the tenant signs to agree the new figure.

So the distinction comes down to consent:

• If the tenant agrees in writing to a new rent, a simple letter or written agreement records that consent and is binding by contract.
• If you want to impose an increase the tenant has not agreed to, you must use the statutory Section 13 procedure on the prescribed form. A letter alone will not bind them.

The rest of this guide unpacks what that means in practice, because the detail is where landlords slip up.

Why the rules changed in 2026

Before the Renters’ Rights Act, many tenancies were assured shorthold tenancies (ASTs) with fixed terms, and rent-review clauses were common, a clause might say “rent increases by 4% each year” or “rent rises in line with RPI.” Landlords often relied on those clauses, or on Section 21 as a backstop to remove a tenant who refused an increase.

That world is gone. As of 1 May 2026:

• Section 21 is abolished. There is no “no-fault” eviction to fall back on if a tenant resists a rise.
• All assured tenancies are periodic. Fixed terms are abolished, so there is no longer a fixed-term rent-review clause to invoke. See our guide to what a periodic tenancy is for the full picture.
• Rent-review clauses are banned. A tenancy agreement can no longer contain a clause that sets out automatic or formula-based increases. Any such clause is unenforceable.
• Section 13 is the only mechanism for a landlord-imposed increase, and it can be used only once in any 12-month period.

Because the contractual shortcuts have been removed, the prescribed Section 13 form has become the centre of gravity for almost every rent increase that is not freely agreed.

What is a rent increase letter?

A rent increase letter is simply a written communication from you to your tenant proposing a new rent. It is not a defined legal instrument. It might say something like: “From 1 September your rent will be £1,150 per month, please let me know if you are happy to continue on that basis.”

There are two scenarios where a letter is genuinely useful:

1. Recording an agreed increase. If you and the tenant discuss the rent and they agree to pay more, perhaps after you have improved the property, or simply as a sensible negotiated step, a letter (or a short written variation both of you sign) records that agreement. Because the tenant has consented, the new rent is binding as a matter of contract; you do not need Section 13 at all.
2. As a courteous heads-up before the formal notice. Many good landlords send a plain-English letter first, explaining why an increase is coming and what the new figure will be, then follow it with the prescribed form. The letter manages the relationship; the form does the legal work.

What a letter cannot do is force an increase on a tenant who has not agreed. If you write “your rent is now £1,150” and the tenant ignores it or objects, you have no enforceable increase. You would still need to serve the prescribed Section 13 form to make it bite.

What is a Section 13 notice?

A Section 13 notice is the statutory route under section 13 of the Housing Act 1988 for a landlord to propose a new rent on a periodic assured tenancy. It must be given on the current prescribed Section 13 form on GOV.UK, not a letter of your own design, and not an old template you downloaded years ago.

The key features in 2026 are:

• Once a year only. You can serve a valid Section 13 notice no more than once in any 12-month period.
• Minimum notice period. The notice must give the tenant at least the statutory minimum period before the new rent takes effect (generally a minimum of one month for tenancies with periods of less than a month, and at least the standard statutory notice for monthly periodic tenancies, confirm the current minimum on the prescribed form and GOV.UK guidance).
• Tenant’s right to challenge. The tenant can refer the proposed rent to the First-tier Tribunal (Property Chamber) before the increase date. Crucially, since the Renters’ Rights Act, the tribunal cannot set the rent higher than the figure you proposed, it can only confirm your figure or set a lower, market-justified one. That change removes the old deterrent where tenants risked the tribunal raising the rent above the landlord’s proposal.
• Effective date. The new rent only takes effect from the date stated in the notice (or a later date the tribunal sets), provided the form was valid and properly served.

If any of these requirements is missed, the notice can be invalid, and an invalid notice means no lawful increase. We cover the specific failure points in invalid Section 13 rent increases.

Side-by-side comparison

Feature	Rent increase letter	Section 13 notice
Legal status	Records consent only; no statutory force	Statutory procedure under Housing Act 1988 s.13
Binds a tenant who has not agreed?	No	Yes (if valid)
Prescribed form required?	No	Yes, current prescribed form on GOV.UK
Frequency limit	None (but any increase still needs consent)	Once per 12 months
Tenant can challenge at tribunal?	N/A (agreed)	Yes, before the increase date
Tribunal can raise above your figure?	N/A	No, it can only confirm or reduce
Best used for	Agreed increases; courtesy heads-up	Imposing a lawful increase without agreement
Risk if done wrong	Tenant simply keeps paying the old rent	Increase void; you wait 12 months to retry

A worked example

Scenario. Priya lets a two-bedroom flat in Leeds on an assured periodic tenancy. The rent is £950 per month. Local rents have risen and she wants to move to £1,025 from 1 September 2026. Her last increase took effect on 1 August 2025.

Step 1, Check the 12-month rule. Her last lawful increase was 1 August 2025. A new Section 13 increase taking effect on 1 September 2026 is more than 12 months later, so the timing is clear.

Step 2, Decide the route. Priya first sends a short, friendly rent increase letter explaining that local rents have risen, the property is in good order, and she proposes £1,025 from 1 September. She invites the tenant to agree.

• If the tenant agrees in writing, that letter (with the tenant’s written acceptance) is enough. The new rent of £1,025 is binding by agreement. No tribunal, no prescribed form needed.
• If the tenant does not respond, or objects, the letter alone achieves nothing. Priya must now serve the current prescribed Section 13 form on GOV.UK, proposing £1,025 and giving at least the statutory minimum notice before 1 September.

Step 3, Serve correctly. Priya completes the prescribed form in full, states the new rent and the date it takes effect (1 September 2026), and serves it in line with the tenancy agreement’s service rules, keeping proof of service.

Step 4, The tenant’s options. The tenant can accept the new rent (by paying it or doing nothing to challenge) or refer it to the First-tier Tribunal before 1 September. If they refer it, the tribunal will assess the open-market rent. Because it cannot exceed £1,025, Priya’s proposed figure, her downside is capped: the worst case is that the tribunal confirms £1,025 or sets something lower if £1,025 is above market.

Outcome. Priya gets either an agreed increase (via the letter) or a lawful imposed one (via the prescribed form), and she has documented the whole process. To sanity-check her figure she could use a free rent increase calculator before sending anything.

When a letter alone is genuinely enough

A standalone letter is sufficient only when both of these are true:

• The tenant expressly agrees to the new rent, ideally in writing; and
• You are not trying to rely on any statutory protection that requires the prescribed form.

Even then, best practice is to capture the agreed change as a short written variation that both parties sign and date, so there is no later dispute about what was agreed. A vague verbal “yeah, that’s fine” is hard to evidence if the relationship sours.

If you have any doubt about whether the tenant truly agreed, treat the situation as a contested increase and use the prescribed Section 13 form. It is the safer default.

When you must use the prescribed Section 13 form

Use the prescribed form whenever:

• The tenant has not agreed to the increase;
• You want certainty that the increase is legally enforceable;
• You may need to rely on the increase in any later possession or arrears proceedings; or
• You simply want to follow the statutory route as a matter of good housekeeping.

Because rent-review clauses are banned and Section 21 is gone, the prescribed form is now the workhorse of rent increases. Most landlords who increase rent regularly will be using it as their standard tool, with letters reserved for the friendly cover note. For the full mechanics, see Section 13 rent increases explained and the step-by-step guide to increasing rent legally.

Common mistakes that void an increase

Even landlords who reach for the right document trip over the detail. Watch for these:

Using an old or self-made form

Only the current prescribed Section 13 form on GOV.UK is valid. A form you saved a couple of years ago may be out of date, and a letter dressed up to look official is not a substitute. Always download the current version at the time you serve.

Increasing more than once in 12 months

You cannot stack increases. A second Section 13 notice within the same 12-month window is invalid. Plan your timing so each increase is at least 12 months after the last.

Getting the notice period or effective date wrong

If the date the new rent is meant to start does not give the tenant the statutory minimum notice, the notice fails. Count carefully from the date of service.

Treating silence as agreement on a letter

If you only sent a letter and the tenant said nothing, you do not have an agreed increase, and you do not have a valid statutory increase either. You have nothing. Silence on a letter is not consent, and a letter is not a Section 13 notice.

Trying to rely on a rent-review clause

Any automatic-increase or formula clause in the agreement is unenforceable post-Renters’ Rights Act. Ignore it and use Section 13.

A pre-send run-through against our rent increase compliance checklist catches most of these before they cost you a year.

Frequently asked questions

Can I just send a letter saying the rent is going up?

You can send the letter, but it only creates a binding increase if the tenant agrees to it. If they do not agree, the letter has no legal effect and you must serve the current prescribed Section 13 form on GOV.UK to impose the increase lawfully.

Is a rent increase letter ever legally binding?

Yes, when it records an increase the tenant has expressly agreed to. In that case the new rent is binding as a matter of contract. The cleanest approach is a short written variation that both you and the tenant sign and date. Without the tenant’s agreement, a letter is not binding.

How often can I increase the rent?

Through the statutory route, no more than once in any 12-month period using a valid Section 13 notice. If the tenant agrees to an increase, that agreement is contractual, but you cannot use repeated agreed increases to dodge the spirit of the once-a-year statutory limit, and most landlords align increases to an annual cycle.

Can the tribunal raise my rent above what I asked for?

No. Since the Renters’ Rights Act 2025, if a tenant refers your Section 13 proposal to the First-tier Tribunal, the tribunal cannot set a rent higher than the figure you proposed. It can confirm your figure or set a lower, market-justified one, so your proposed rent is effectively the ceiling for that round.

Do I still need a Section 13 notice if my tenancy agreement has a rent-review clause?

Yes. Rent-review clauses are banned and unenforceable under the Renters’ Rights Act. You cannot rely on the clause, so any landlord-imposed increase must go through the Section 13 process on the prescribed form unless the tenant separately agrees in writing.

What happens if my Section 13 notice is invalid?

An invalid notice produces no lawful increase, and you generally have to wait until you can serve a fresh valid notice, potentially losing a year of higher rent. Common causes are using an out-of-date form, breaching the once-a-year rule, or getting the effective date wrong. See our guide to invalid Section 13 rent increases.

Bringing it together

The practical takeaway is simple. A rent increase letter is a relationship tool: use it to propose a figure, explain your reasons and capture an agreed increase. The prescribed Section 13 notice is the legal tool: use it whenever you need to impose an increase the tenant has not agreed, or whenever you want cast-iron enforceability. Many of the best landlords use both, a courteous letter first, then the prescribed form to make it binding if needed, and they diary the 12-month cycle so they never serve too soon. For the exact wording, see our Section 13 rent increase template.

Coming soon

Tenancy Pilot is launching soon, and its rent increase notice generator is built precisely for the choice this guide describes. It will help you draft a clear cover letter, produce a compliant notice aligned to the current prescribed form, check your 12-month timing automatically, and store proof of service, all from one command centre with deadline alerts so you never serve too early. Want it the moment it goes live? Join the waitlist and be first to use the rent increase tools.

This guide is general information for England landlords, not legal advice. Rules change and individual circumstances vary. Always check the current position on GOV.UK and legislation.gov.uk, use the current prescribed forms, and consult a qualified solicitor before acting.