Family leave
Maternity leave dates calculator
One due date and one planned start: every deadline and every end date of your maternity leave, on a Sunday-to-Saturday calendar.
Checked by Radif Partners · Editorial policy · Method and sources
Statutory Maternity Leave is 52 weeks long for every employee, whatever their length of service, hours or pay: 26 weeks of Ordinary Maternity Leave followed by 26 weeks of Additional Maternity Leave. The earliest it can start is the Sunday 11 weeks before the expected week of childbirth, and your employer must know the due date and your chosen start by the end of the qualifying week, 15 weeks before that week. Two events can start it sooner than planned: a birth before the chosen date, which starts leave the next day, and any pregnancy-related absence in the 4 weeks before the due week. 2 weeks after the birth are compulsory, 4 for factory workers. If the baby is due on 20 April 2027 and leave starts on 4 April 2027, the full leave ends on 1 April 2028, and returning before then needs 8 weeks’ notice.
Return to work after the full 52 weeks on
2 April 2028
| Expected week of childbirth starts (Sunday) | 18 April 2027 |
| Qualifying week (15th week before) | 3 January 2027 to 9 January 2027 |
| Tell your employer about the pregnancy and leave by | 9 January 2027 |
| Earliest start of maternity leave | 31 January 2027 |
| Pregnancy-related absence triggers leave from | 21 March 2027 |
| Ask for SMP (28 days before it starts) by | 7 March 2027 |
| Ordinary maternity leave ends | 2 October 2027 |
| SMP ends (39 weeks) | 1 January 2028 |
| Additional maternity leave ends (52 weeks) | 1 April 2028 |
Weeks run Sunday to Saturday. If the baby arrives before leave starts, leave starts the day after the birth. To come back before the 52 weeks are up, give 8 weeks’ notice of the new date.
The example, date by date
The calculator opens on a baby due on 20 April 2027 and leave planned from 4 April 2027. Here is what it works out, and why:
| Step | Date | Rule |
|---|---|---|
| Expected week of childbirth begins | 18 April 2027 | The Sunday on or before the due date |
| Qualifying week | 3 January 2027 to 9 January 2027 | 15th week before the due week |
| Tell your employer by | 9 January 2027 | End of the qualifying week |
| Earliest possible start | 31 January 2027 | 11 weeks before the due week |
| Pregnancy-related absence starts leave from | 21 March 2027 | 4 weeks before the due week |
| Ordinary Maternity Leave ends | 2 October 2027 | 26 weeks from the start |
| Additional Maternity Leave ends | 1 April 2028 | 52 weeks from the start |
| First day back | 2 April 2028 | No notice needed |
Suppose the plan changes and you want to come back on 2 January 2028, the day after the last week of Statutory Maternity Pay. You would need to tell your employer by 7 November 2027, 8 weeks before.
Why the halfway point matters
The 26-week boundary between ordinary and additional leave changes what you come back to. After ordinary leave alone, you return to the same job. After additional leave, you return to the same job unless that is not reasonably practicable, in which case the employer must offer another job that is suitable for you and appropriate in the circumstances (regulation 18 of the 1999 Regulations). Anyone planning to stay away for six calendar months should check the end date: six months is a few days longer than 26 weeks, which is enough to fall into additional leave.
The automatic triggers
You do not fully control the start. If you are off work for a reason connected with the pregnancy on any day from the Sunday 4 weeks before the due week, leave and pay start the next day, even if you had planned to work until the due date. Ordinary sickness unrelated to the pregnancy does not trigger it. A birth before your planned start date also starts leave on the following day, and your employer will then need the birth certificate or a document signed by a doctor or midwife giving the actual date. The calculator keeps the deadlines that depend on the due date, which do not move when the baby arrives early.
Northern Ireland
The leave calendar is the same: 52 weeks split into two halves of 26, notice by the 15th week before the due week, earliest start 11 weeks before, and 8 weeks’ notice to come back early (nidirect, Statutory Maternity Leave). To add the money to the dates, use the maternity pay calculator; to see how holiday builds up during these weeks, read holiday on maternity leave.