Pregnancy Due Date Calculator
Estimated due date, current week and trimester from the last period.
Result
How to use
- 1
Pick the first day of your last menstrual period.
- 2
Adjust the cycle length if it is not 28 days.
- 3
See the estimated due date, current week and trimester.
Questions
How is the due date estimated?
By Naegele's rule: 280 days (40 weeks) from the first day of the last period, adjusted for cycle length.
How accurate is it?
Only a small share of babies arrive exactly on the due date. Your doctor may update it after an ultrasound scan.
About this Due Date tool
Pregnancy Due Date Calculator — Estimated due date, current week and trimester from the last period. It is one of 200 free tools on namasivayam.in, made by software engineer Namasivayam Vadivelan for everyday use in India.
Everything is calculated instantly in your browser: nothing you type or upload is sent to any server, there is no sign-up, and it works on mobile and desktop. Pick the first day of your last menstrual period.
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Results are estimates to help you plan. They are not financial, tax or medical advice.