How far along am I? Pregnancy week calculator

Your gestational age is the number of days since the first day of your last period, written as weeks + days. Providers write 23+4 or 23w4d; both mean 23 full weeks and 4 days. When people say they are 23 weeks pregnant, they usually mean 23 completed weeks, so they are in the 24th week.

Worked example: your last period started on 06/01/2026 and today is 11/13/2026.

• Days since your LMP: 165
• 165 ÷ 7 = 23 weeks, remainder 4 days, so you are 23 weeks 4 days pregnant
• That's the second trimester
• Estimated due date: 06/01/2026 + 280 days = 03/08/2027

The calculator does this for you, adjusts for cycles that aren't 28 days, and also shows a progress bar for how much of the 40 weeks is behind you.

This page adds a date picker the due date calculator doesn't have. Enter any date, and you get your gestational age and trimester on that day.

Example: with the same LMP of 06/01/2026, on 12/25/2026 you will be 29 weeks 4 days, in the third trimester. On 01/01/2027 you'll be 30 weeks 4 days.

That's handy when you're:

• planning a trip or a wedding and want to ask your provider whether the timing works
• telling your employer when you plan to start leave
• booking a class, a photo session or a visit from family
• matching a past date to your week, such as when you first felt movement

If the date falls before the pregnancy started or more than 44 weeks after your LMP, the calculator tells you it's outside the pregnancy.

Providers use weeks because months have different lengths. Here's how the weeks line up, using ACOG's trimester and term definitions:

Weeks + days	Where you are
0+0 to 13+6	First trimester
14+0 to 27+6	Second trimester
28+0 onward	Third trimester
37+0 to 38+6	Early term
39+0 to 40+6	Full term
41+0 to 41+6	Late term
42+0 or later	Postterm

Forty weeks (280 days) is a little more than nine calendar months. From an LMP of 01/10, for example, the due date of 10/17 is 9 months and 7 days later. Ways of turning weeks into months differ from one book or app to the next, so it's easiest to go by weeks, the way your provider does.

The calculator gives the same answer from any of its five starting points, as long as your input is accurate. Choose the one you trust most:

• Last period: the default. Best if you know the date and your cycles are fairly regular.
• Ultrasound: enter the scan date and the age it measured. ACOG considers a first-trimester ultrasound the most accurate way to date a pregnancy.
• Due date: if your provider has already given you one, enter it so your weeks match their chart.
• IVF transfer: enter the transfer date and embryo age (day 3, 5 or 6). See the IVF due date calculator for how this works.
• Conception date: if you know when you ovulated or conceived.

The due date calculator also compares your LMP date with your ultrasound and tells you which one ACOG's rule favors.

Besides your week and trimester today, you'll see your estimated due date and days to go, your ACOG term stage, the estimated conception date, and the dates you reach 37, 40 and 42 weeks. A timeline lists key windows such as first-trimester screening, the anatomy scan and glucose screening, and you can download it as a calendar file (.ics).

There is also a link to your current week in pregnancy week by week, with your baby's size and what to expect.

Everything runs in your browser and nothing is saved. This calculator is informational and is not a substitute for medical advice. Whatever week you're in, call your provider or labor and delivery right away for bleeding, leaking fluid, severe pain or a baby who is moving less than usual; in an emergency, call 911.