Pregnancy Due Date Calculator
Find your estimated due date, see how far along you are, and follow your pregnancy week by week. Free, private, and everything stays in your browser.
Calculate your due date
This tool provides general information only and is not medical advice. Confirm your due date and care plan with your healthcare provider.
How the calculation works
- Last period: we add 280 days (40 weeks) to the first day of your last period, then adjust for your cycle length. A 32-day cycle shifts the due date 4 days later than a 28-day cycle.
- Conception date: pregnancy lasts about 266 days (38 weeks) from conception, so we add 266 days to the date you entered.
- IVF transfer: a day 5 transfer is dated as 19 days of pregnancy already; a day 3 transfer as 17 days. We add the remaining days (261 or 263) to reach 280.
- Known due date: from an ultrasound, we count backward to show your current week and day.
Trimesters at a glance
First trimester: weeks 1 to 13. The foundation of development, and often the toughest weeks for nausea and fatigue.
Second trimester: weeks 14 to 27. Many people feel more energy here. The anatomy scan usually happens around week 20.
Third trimester: weeks 28 to 40. Rapid growth, and your baby prepares for birth. Week 24 is considered the viability milestone.
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