Maternity dates start from your due date
Most maternity leave and pay rules are calculated from your due date. This calculator takes your due date and works out the dates you are most likely to need, using the UK system as a detailed example because it defines its milestones precisely, plus general return dates that apply anywhere.
UK statutory milestones
| Milestone | How it is worked out |
|---|---|
| Expected week of childbirth (EWC) | The Sunday-to-Saturday week containing your due date |
| MATB1 certificate | Can be issued from 20 weeks before the EWC |
| Qualifying week | The 15th week before the EWC — tell your employer by the end of it |
| Earliest leave start | The start of the 11th week before the EWC |
Rules, eligibility and pay change over time, so always check the current official guidance (GOV.UK in the UK) and your employer’s policy.
Other countries
Leave rules vary widely. In the United States, the Family and Medical Leave Act (FMLA) provides up to 12 weeks of unpaid, job-protected leave for eligible employees, and some states add paid leave. Many countries offer longer paid leave and parental leave that can be shared. Your HR department or a government website is the best source for your situation.
Return dates
The calculator shows when you would return after 12, 16, 26, 39 or 52 weeks if your leave starts on your due date. If your leave starts earlier — or your baby arrives early — the return date moves accordingly. The Date Calculator can count from any start date.