Pregnancy calendar week by week
Get a personal pregnancy calendar that shows when every week starts and ends, so you can match appointments to the right week.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter first day of your last period and average cycle length.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Start = first day of last period + (cycle length - 28). Week n starts 7 × (n - 1) days later and ends 7 × n - 1 days later. Weeks 1 to 14 are the first trimester, 15 to 28 the second, 29 to 40 the third.
Example
Inputs: First day of your last period = 2026-01-01, Average cycle length = 28 days. Result: Estimated due date: Thursday, October 8, 2026 (2026-10-08).
Limits and caveats
- The calendar follows the estimated date; if your doctor changes it after a scan, recalculate.
- The table runs to week 40, though some pregnancies go to 42 weeks.
Questions about this tool
Does week 12 mean 12 full weeks?
No. Week 12 means you have completed 11 weeks and are living through the days of the 12th week.
When does the first trimester end?
At the end of week 14 in the table, which is 13 weeks and 6 days.
Can I print the table?
Yes, use your browser’s print command to save it on paper or as a PDF.