Maternity leave dates calculator

Every date that follows from a due date: when to tell your employer, when leave can start, when pay stops and when leave ends.

The one people miss is the notice deadline. It falls at the end of the fifteenth week before the birth — about six months beforehand — and passing it can delay your pay.

The due date on your MATB1 certificate.

Optional. Leave blank to use the earliest possible date.

Compulsory leave after the birth is four weeks rather than two.

The short version

Notice deadline
The end of the 15th week before the baby is due. Roughly six months ahead.
Earliest start
11 weeks before the expected week of childbirth.
Compulsory leave
Two weeks after the birth, four for factory work. It cannot be waived.
Automatic start
Leave begins on its own if the baby comes early, or on a pregnancy-related absence in the last four weeks.
Everything counts back
All the dates run from the Sunday starting the expected week, not from the due date itself.

Common questions

When do I have to tell my employer I am pregnant?

By the end of the 15th week before the baby is due — about six months beforehand. You must give the due date and when you want leave to start. Missing it can delay your statutory maternity pay, though your right to leave itself is not lost if it was not reasonably practicable to tell them in time.

When is the earliest I can start maternity leave?

Eleven weeks before the expected week of childbirth. Starting that early means the leave and the pay both start then, so most people start later to keep more of the paid period after the birth.

What happens if the baby comes early?

Leave starts automatically the day after the birth, whatever you had planned. The full 52 weeks still runs from that point, so nothing is lost — the dates simply move.

Can I change my leave start date?

Yes, with 28 days’ notice before the new date or the original one, whichever is earlier. Employers can be more flexible, but 28 days is the statutory requirement.

Do I have to take all 52 weeks?

No, only the compulsory two weeks after the birth — four if you work in a factory. Beyond that you can return whenever you like, giving eight weeks’ notice of an early return.

Does holiday build up while I am on maternity leave?

Yes, throughout all 52 weeks, including bank holidays if they form part of your entitlement. Most people take the accrued leave immediately before or after the maternity leave itself.

What the terms mean

Expected week of childbirth (EWC)
The week the baby is due, running Sunday to Saturday. Every maternity date is counted from the Sunday that starts it.
Qualifying week
The 15th week before the expected week of childbirth. Both the service test and the earnings test are measured against it.
Compulsory maternity leave
Two weeks immediately after the birth, four in a factory, which you must take. It is the only leave in UK law that cannot be waived.
Ordinary maternity leave
The first 26 weeks. You return to the same job.
Additional maternity leave
The second 26 weeks. You may return to a similar job if it is not reasonably practicable to return to the same one.
MATB1
The certificate from a midwife or doctor confirming the due date, issued from around week 20 and needed to claim statutory maternity pay.

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