How much can I increase rent by and how often?

The rules on rent increases changed on 1 May 2026, when the Renters' Rights Act 2025 took effect and they're easy to get wrong.

The short version: yes, you can still increase the rent, but there's now only one lawful way to do it, you can only do it once a year, and how you set the figure matters more than it used to.

How often can you increase the rent?

Once every twelve months, no more. You can't raise the rent within the first 52 weeks of the tenancy, and after that, only once in any twelve month period. The days of small, frequent increases are over.

If you increased the rent shortly before the rules changed — whether through a rent review clause or an informal agreement — you'll need to wait a full 52 weeks from that point before a new increase can take effect.

How much can you increase it by?

There's no fixed legal cap on the amount you can propose. But that doesn't mean you can put it up by whatever you like, because of one important safeguard: your tenant can challenge the increase, and it has to stand up as being in line with the open market rent for similar properties in the area.

In practice, the local market is your ceiling. Propose something well above it and you're likely to have it knocked back (more on that below).

So the honest answer is: as much as the market genuinely supports, and no more.

There's now only one lawful way to do it

This is the change that catches most landlords out. From 1 May 2026, the only legal way to increase the rent on a periodic tenancy is by serving a formal Section 13 notice using the prescribed Form 4A. That's it.

Crucially, rent review clauses no longer work. Any clause in your tenancy agreement that automatically raised the rent (a fixed percentage each year, a CPI or RPI link, a stepped increase, anything like that) is now void, on both new and existing tenancies. Likewise, an informal "we'll put it up by £50 from next month" agreement isn't a valid increase. If it's not done by Form 4A, it doesn't count.

You must also give your tenant at least two months' notice before the new rent takes effect (up from one month under the old rules).

Your tenant can challenge it — and the risk now sits with you

Tenants have always been able to refer a proposed increase to the First tier Tribunal, but the rules have flipped in a way every landlord needs to understand.

Under the new system, the tribunal can only confirm or reduce the rent you proposed. It can never set it higher. Previously, a tribunal could actually raise the rent above what the landlord asked for, which put tenants off challenging. That deterrent is gone. Now a tenant can challenge an increase for a £47 application fee (at the time of writing) knowing the figure can only stay the same or come down, so challenges are expected to become far more common.

Three more things that shifted in the tenant's favour:

No backdating. If a tenant challenges, the rent stays at the old figure throughout the process, and any increase the tribunal allows only takes effect from a date the tribunal sets — usually the next rent date after its decision, not the date on your notice. So a challenge effectively delays your increase.

Hardship deferral. If paying the new rent straight away would cause the tenant genuine hardship, the tribunal can push the start date back by up to a further two months.

A rejected increase costs you a full year. If the challenge succeeds, the clock resets — you cannot serve another Section 13 notice for 52 weeks from the date of the tribunal's determination. So the cost of over asking isn't just the difference in rent; it's twelve months of not being able to try again.

There is a deadline on the tenant's side, though. They must get their application to the tribunal before the new rent is due to start — once that date passes without a challenge, the increase simply takes effect.

The practical message: there's no upside to over asking. Propose a punchy, above market figure and the best case is the tribunal trims it to market anyway, while you've lost time and goodwill. A sensible, market based increase is far more likely to be accepted without challenge which is exactly what you want.

The mistakes that invalidate an increase

Because the process is now strict, small errors cost you the whole increase and mean starting again:

Using the old Form 4 instead of Form 4A. Giving less than two months' notice. Trying to increase too soon — inside 52 weeks of the tenancy, or within twelve months of the last increase. Setting a start date mid period. The new rent must take effect at the start of a rent period. If your tenant pays on the 5th, the increase has to begin on the 5th, not the 1st. Relying on an old "rent increase" clause in the agreement. These no longer work. You must serve a Form 4A notice to raise the rent, whatever the agreement says.

There's no such thing as a partly valid notice, if it's wrong, the rent simply doesn't go up until a correct notice has run its full course.

Getting it right

The smart approach now is to treat a rent increase as something to evidence, not just declare.

Before you propose a figure, look at what genuinely comparable properties in the area are actually letting for, so your number is defensible if it's ever questioned. Keep a note of those comparables at the time you serve the notice, not months later if a challenge lands.

Download Form 4A fresh from GOV.UK each time rather than reusing a saved copy. The wording is updated periodically, and serving a superseded version hands a challenging tenant an easy argument.

Then serve the correct form, give the full notice, and keep it to once a year. Done that way, increasing the rent stays perfectly straightforward, and it simply rewards a bit of preparation.

Renting out in Greenford?

If you'd like a realistic view of what your property could achieve in today's Greenford market, whether you're thinking about a rent review or just weighing up your options, we're always happy to help.

Get in touch with the team at Argant Estates for a free, no obligation valuation. No strings, and no need to be looking to switch or sign up to anything.

Argant Estates — local property specialists, Greenford

Disclaimer

This article is for general informational purposes only and does not constitute legal, financial, or professional advice. While we strive to ensure accuracy, property laws, regulations and market conditions may change over time. We do not guarantee the completeness, reliability or current validity of the information provided.

Readers should independently verify information and seek professional guidance before making any property related decisions. Argant Estates is not liable for any losses or damages resulting from reliance on this content.