CALCULATOR · FREE免费 · Free
Due Date Calculator
Enter the first day of your last period to estimate a due date 280 days later. This is an estimate, not medical advice.
--Due year · year
--Due month · month
--Due day · day
--Due date · date
Estimates only; verify on site before ordering or building.
Example
| Item | Value | Unit |
|---|---|---|
| LMP year | 2026 | year |
| Month | 1 | month |
| Day | 1 | day |
| Due year | 2026 | year |
| Due month | 10 | month |
| Due day | 8 | day |
| Due date | 2026-10-08 | date |
Where people go wrong
- Swapping month and day, which moves the result by months.
- Adding 280 days to the conception date instead of the first day of the last period.
- Forgetting that an ultrasound can revise the due date.
FAQ
How accurate is a due date?
A due date is the center of a range, not an exact delivery day; only about 4 percent of babies arrive on it.
What if my cycles are irregular?
Use an early ultrasound, which is usually more accurate than LMP; have your clinician confirm.