๐คฐ Pregnancy Week Calculator
Enter your last period date to calculate
This estimate uses Naegele's rule and is for reference only. Follow your doctor's guidance for actual care.
Enter your last menstrual period to calculate your current gestational age and an estimated due date. Useful as a reference alongside your prenatal checkup schedule or when thinking about when to share the news.
How to use
- Enter the first day of your last menstrual period.
- Your current gestational age and trimester are shown automatically.
- Check your estimated due date and the number of days remaining.
FAQ
How is the due date calculated?
Using Naegele's rule โ 280 days (40 weeks 0 days) after the first day of your last menstrual period.
What if my doctor gave me a different due date?
This tool uses a general formula as a reference. An ultrasound-based estimate from your doctor is more accurate, so always defer to your healthcare provider's assessment.
How are the trimesters defined?
It follows the common convention of weeks 0-15 as the first trimester, 16-27 as the second, and 28 onward as the third.
Is this accurate if my cycle isn't 28 days?
This formula assumes a standard 28-day cycle. If your cycle differs significantly, the estimate may drift from your actual gestational age, so confirm with your healthcare provider.
Can I use this to plan prenatal checkup timing?
Yes โ knowing your current gestational age gives you a rough sense of upcoming checkup timing, though you should always follow your provider's actual schedule.