Estimate your due date from the first day of your last period (adjusted for cycle length), from the conception date, or from an IVF transfer date.
See how far along you are in weeks and days, your trimester, the days to go and a table of key milestones and common check-ups.
How to use it
- Choose the calculation method.
- Enter the date and your usual cycle length if using last period.
- Read the due date, pregnancy age and timeline.
Features
- 4 methods: last period, conception, IVF day 3 or day 5.
- Adjusted for cycle length.
- Weeks, days and trimester.
- Milestones and check-up dates.
- Visual progress bar.
Tip: Note the first day of your last period accurately and bring the result to your first appointment; your doctor will confirm it by ultrasound.
How is the due date calculated?
The standard medical method (Naegele's rule) adds 280 days — 40 weeks — to the first day of your last period, assuming a 28-day cycle. If your cycle is longer or shorter, the tool shifts the date by the difference. For IVF the calculation is more precise because the transfer date is known exactly.
Pregnancy stages by week
| Stage | Weeks |
|---|---|
| First trimester | 1 to 13 |
| Second trimester | 14 to 27 |
| Third trimester | 28 to birth |
| Full term | About 39 to the end of 40; 37–42 is within the usual range in medical classifications |
The calculator's date is an estimate for planning. Your doctor sets the official date, usually by a first-trimester ultrasound, which is the most accurate.
Important: this tool doesn't replace care from a doctor or midwife. For any bleeding, severe abdominal pain, severe headache with vision changes, leaking fluid or a clear drop in baby's movements, contact your doctor or go to the emergency department straight away.
Privacy
The tool runs in your browser and your data is not sent to our servers. Free, with no sign-up.