Pregnancy Due Date Calculator
Pregnancy Due Date Calculator estimates your due date from your last period (adjusted for cycle length) or conception date, and shows gestational age, trimester ranges and days remaining.
Last updated: July 2026
A due date calculator estimates when your baby is due by adding 280 days to the first day of your last menstrual period, adjusted for your cycle length, or 266 days to the conception date. It also shows your current gestational age in weeks and days and your trimester date ranges.
How to use Pregnancy Due Date Calculator
- Choose to calculate from your last period or conception date.
- Enter the date (and your average cycle length for the period method).
- Read your estimated due date, gestational age and trimester dates.
Frequently asked questions
How is the due date calculated?
280 days from the first day of your last period, adjusted by your cycle length minus 28 — or 266 days from the conception date.
How accurate is it?
It's an estimate based on averages — only about 1 in 20 babies arrive on their due date. Your provider may adjust it after an ultrasound.
Is my data stored?
No — all calculations run in your browser. Nothing is uploaded or saved.
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