Pregnancy Weeks to Months Converter
Enter how many weeks pregnant you are to see which month of pregnancy you are in, your trimester and the exact calendar months, or pick a month to see the weeks it covers. The full chart from week 1 to 40 is below.
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How to use the Pregnancy Weeks to Months Converter
- Choose a direction: weeks to months, or month to weeks.
- Enter weeks pregnant (and extra days if you know them), or pick a month.
- Press Convert to see the month, trimester and exact calendar months.
- Use the 40-week chart below to look up any other week.
Pregnancy month chart
| Month | Weeks pregnant | Trimester |
|---|---|---|
| Month 1 | Weeks 1–4 | First |
| Month 2 | Weeks 5–8 | First |
| Month 3 | Weeks 9–13 | First |
| Month 4 | Weeks 14–17 | Second |
| Month 5 | Weeks 18–22 | Second |
| Month 6 | Weeks 23–27 | Second |
| Month 7 | Weeks 28–31 | Third |
| Month 8 | Weeks 32–35 | Third |
| Month 9 | Weeks 36–40 | Third |
Two ways to count months
The pregnancy month chart (above) groups the 40 weeks into nine blocks so each trimester is three months. It is what people usually mean by "how many months pregnant".
Exact calendar months divide the days since your last period by the average month length: months = (weeks × 7 + days) ÷ 30.4375. For example, 30 weeks = 210 days ÷ 30.4375 ≈ 6.9 months. The two methods can differ by close to a month, which is why friends and apps sometimes give different answers. Neither is wrong; they just count differently.
Remember that the count starts from the last period, about two weeks before conception, so the baby's own age is roughly two weeks less than the pregnancy age.
Frequently asked questions
How many months is 24 weeks pregnant?
24 weeks pregnant is in the 6th month of pregnancy on the standard chart (month 6 covers weeks 23 to 27). In exact calendar terms, 24 weeks is 168 days, about 5.5 months since the first day of the last period.
Why can't I just divide weeks by 4?
Months are longer than 4 weeks: an average month is about 4.35 weeks (30.44 days). Dividing by 4 makes a 40-week pregnancy look like 10 months. The usual pregnancy chart splits 40 weeks into 9 months of 4 or 5 weeks each, so it matches the familiar "nine months".
Is pregnancy 9 months or 10 months?
Both descriptions are used. A 40-week pregnancy counted from the last period is 280 days, which is about 9.2 calendar months. Grouped in exact 4-week blocks it would be 10 "lunar months". Most US doctors and apps use the 9-month chart shown here.
What weeks are each trimester?
The first trimester is weeks 1 to 13 (through 13 weeks 6 days), the second is weeks 14 to 27, and the third is week 28 until birth. Some sources start the third trimester at week 27 or 29; this converter uses 28, as ACOG does.
Does "13 weeks pregnant" mean the 13th week?
Not exactly. 13 weeks pregnant means 13 full weeks have passed, so you are in the 14th week. This converter follows the common convention of charting completed weeks, so 13 weeks pregnant appears in month 3 and the first trimester.
How are pregnancy weeks counted?
From the first day of your last menstrual period (LMP), about two weeks before conception. That is why you are already considered "4 weeks pregnant" around the time of a missed period.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.