How to read it
Each row is one completed week, dated from your last period or worked back from your due date. The coloured bar on the left marks the trimester. Milestones are the timings most antenatal schedules share; your clinic's letter always wins if it differs.
Two things surprise people. First, you are "4 weeks pregnant" on the day your period is due, because counting starts two weeks before conception. Second, the due date is week 40 but the calendar runs to week 42, because roughly half of first babies arrive after the due date.
Related tools
For a single weeks-and-days figure, use how far along am I. To convert weeks to months, the weeks to months calculator does it. And the maternity leave planner lays your leave over the same dates.
Frequently asked questions
How is a pregnancy calendar counted?
From the first day of your last period, which is week 0. Each row covers seven days, so week 12 runs from 12 weeks 0 days to 12 weeks 6 days. Your due date is the first day of week 40. If you enter a due date instead, the calendar counts back 280 days to find week 0.
When do the trimesters start and end?
The first trimester is weeks 0 to 13, the second is weeks 14 to 27, and the third is week 28 until birth. Different sources shift the boundaries by a week or so; the calendar uses the most common 14 and 28 week split that ACOG describes.
Which appointments and scans are on the calendar?
The usual timings: a first antenatal visit at 8 to 10 weeks, NIPT from 10 weeks, a dating scan at 11 to 14 weeks, the anatomy scan at 18 to 22 weeks, glucose screening at 24 to 28 weeks, the whooping cough vaccine at 27 to 36 weeks, anti-D at 28 weeks if you are Rh negative, and the group B strep swab at 36 to 37 weeks. Your clinic's schedule may differ.
Why does the calendar show 42 weeks?
Because pregnancies routinely run past the due date. Weeks 40 and 41 are late term and most clinicians discuss induction during week 41. A pregnancy reaching 42 weeks is post-term, and induction is generally recommended by then.
Can I print it?
Yes. The Print button prints the table with the trimester colour bars and milestones, without the form. The address bar keeps your dates so you can bookmark the page.
These calculators give estimates based on cycle averages and standard formulas. They are for general information only and are not medical advice. For anything concerning your health or pregnancy, talk to a qualified healthcare provider.