Your pregnancy, counted in days
Weeks are the standard way to describe a pregnancy, but days can be more satisfying — and more precise. This Due Days Calculator shows:
- Today’s pregnancy day — out of about 280;
- Days pregnant — completed days since the start of your last period;
- Days left until your due date and until full term at 39 weeks;
- Days to every milestone — the end of the first trimester, the anatomy-scan window, the third trimester, early and full term — or how long ago each one was.
Days, weeks and months
| Days pregnant | Weeks + days | Stage |
|---|---|---|
| 28 | 4w 0d | Around the missed period |
| 97 | 13w 6d | Last day of the first trimester |
| 140 | 20w 0d | Halfway |
| 196 | 28w 0d | Third trimester begins |
| 259 | 37w 0d | Early term |
| 280 | 40w 0d | Due date |
Note the off-by-one difference between “days pregnant” (completed days) and “day of pregnancy” (today’s number): on day 1 you are 0 days pregnant, just as a baby is 0 days old on the day it is born.
Why count days?
Some tests and treatments are timed to the day — for example screening windows that close at 13 weeks 6 days. Counting days removes any confusion between “week 20” and “20 weeks”. It is also a nice way to mark progress: day 100, day 200, and the final countdown. For a simple countdown to the due date, see the Days Until Due Date Calculator.