Section 13 Notice Period: The Two-Month Rule Explained

Two Full Calendar Months, Not 60 Days

Every Section 13 rent increase in England requires at least two full calendar months between the date the tenant receives Form 4A and the proposed effective date. This is a calendar-month count, not a day count. Two months from 15 January is 15 March — regardless of whether February has 28 or 29 days.

If you serve on the last day of a month that is longer than the month two months later, the rule still applies. Serve on 31 August and two full calendar months takes you to 31 October. Serve on 30 November and two full months ends on 30 January.

The Effective Date Must Also Align With a Rent Period

Meeting the two-month minimum is not enough on its own. The proposed effective date on Form 4A must fall on the first day of a tenancy rental period. For a monthly tenancy where the rental period starts on the 1st, the effective date must be the 1st of a month. For a tenancy where the rental period starts on the 15th, the effective date must be a 15th.

This creates a practical constraint. You might calculate that two months from service lands on 14 March, but if the rental period starts on the 1st, the earliest valid effective date is 1 April — the next rent-period start after the two-month minimum has passed.

Postal Deeming Adds Extra Days

If you serve Form 4A by first-class post, the tenant is deemed to have received it two working days after you post it. The two-month notice period starts from that deemed service date, not from the date you dropped the letter at the post office.

Working days exclude weekends and bank holidays. Post on a Thursday before Good Friday, and the two working days are the following Tuesday and Wednesday — skipping the Friday, Saturday, Sunday, and Monday bank holiday.

Build a three-day buffer into your posting date to absorb any deeming-day uncertainty. Better to serve a week early than to miss by a day and have the entire notice ruled invalid.

Timing Examples

Monthly tenancy, rental period starts on the 1st:

You want the new rent to start 1 March 2027. Two full calendar months before that is 1 January 2027. If you serve personally on or before 1 January, the timing is valid. If you serve by post, you need deemed service to complete by 1 January — meaning you should post by 29 December 2026 at the latest (allowing two working days), or earlier if those dates fall on a weekend or bank holiday.

Monthly tenancy, rental period starts on the 15th:

Target effective date: 15 April 2027. Two months before: 15 February 2027. Personal service must happen by 15 February. For postal service, post by Thursday 11 February at the latest so deemed service occurs by 15 February, assuming no bank holiday affects the count.

Weekly tenancy, rental period starts Mondays:

Target effective date: the first Monday that is at least two full calendar months after service. If you serve personally on 10 June 2027, two calendar months is 10 August. The first Monday on or after 10 August becomes the effective date, if the tenancy rental period starts on Mondays.

What Happens If You Get It Wrong

A Form 4A notice served with less than two full calendar months' notice is invalid. The tenant can ignore it, and if you try to enforce the increase, they can refer it to the First-tier Tribunal where it will be struck down as procedurally defective.

Crucially, an invalid notice does not count toward the 52-week frequency limit. But it does mean you must serve a fresh, correctly dated Form 4A — and the full two-month clock restarts from that new service date. The practical cost is delay: months of lost rental income that you cannot recover.

Get the Full Timeline Right

The two-month notice period is one piece of a three-part timing puzzle: the 52-week frequency rule, the two-month minimum notice, and the rent-period alignment. Our Section 13 rent increase guide walks through all three with worked date calculations and a printable timeline planner so nothing slips through the cracks.

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