Due Date Calculator
Estimated delivery date and pregnancy milestones.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Estimated due date
- 2026-12-06 (Sunday)
- Gestational age today
- 21 weeks, 2 days
- Trimester
- Second
- Conception (approx)
- 2026-03-15
- Days remaining
- 131
Quick answer
Naegele's rule estimates the due date as 280 days from the first day of the last menstrual period.
Due date = LMP + 280 days
How to use the Due Date Calculator
- 1Enter the first day of your last period.
- 2Adjust your average cycle length.
- 3Read the due date and current gestational age.
Frequently asked questions
How accurate is the due date?
Only about 4% of babies arrive on the estimated date; roughly 80% arrive within two weeks either side.
Why count from the last period?
Ovulation is hard to pin down, but the last period is a date most people know, so obstetrics standardised on it.