# Weeks pregnant in months

> A pregnancy of 40 weeks is about 9 months and 1 week, because a month averages 4.345 weeks. To convert, divide the weeks by 4.345: 24 weeks is 5.5 months, so month 6 of pregnancy. Counting 4 weeks per month falls short, since 9 × 4 is only 36 weeks. The chart below converts all 40 weeks.

Source: https://www.calterix.com/en-us/calculator/due-date/weeks-pregnant-in-months/ · Updated 11/06/2026 · en-US

## Chart: weeks pregnant in months

The chart turns each of the 40 weeks into a pregnancy month, completed months, and trimester.

| Week | Pregnancy month | Completed months | Trimester |
| --- | --- | --- | --- |
| 1 | Month 1 | 0 | 1st trimester |
| 2 | Month 1 | 0 | 1st trimester |
| 3 | Month 1 | 0 | 1st trimester |
| 4 | Month 1 | 0 | 1st trimester |
| 5 | Month 2 | 1 | 1st trimester |
| 6 | Month 2 | 1 | 1st trimester |
| 7 | Month 2 | 1 | 1st trimester |
| 8 | Month 2 | 1 | 1st trimester |
| 9 | Month 3 | 2 | 1st trimester |
| 10 | Month 3 | 2 | 1st trimester |
| 11 | Month 3 | 2 | 1st trimester |
| 12 | Month 3 | 2 | 1st trimester |
| 13 | Month 3 | 2 | 1st trimester |
| 14 | Month 4 | 3 | 2nd trimester |
| 15 | Month 4 | 3 | 2nd trimester |
| 16 | Month 4 | 3 | 2nd trimester |
| 17 | Month 4 | 3 | 2nd trimester |
| 18 | Month 5 | 4 | 2nd trimester |
| 19 | Month 5 | 4 | 2nd trimester |
| 20 | Month 5 | 4 | 2nd trimester |
| 21 | Month 5 | 4 | 2nd trimester |
| 22 | Month 6 | 5 | 2nd trimester |
| 23 | Month 6 | 5 | 2nd trimester |
| 24 | Month 6 | 5 | 2nd trimester |
| 25 | Month 6 | 5 | 2nd trimester |
| 26 | Month 6 | 5 | 2nd trimester |
| 27 | Month 7 | 6 | 2nd trimester |
| 28 | Month 7 | 6 | 3rd trimester |
| 29 | Month 7 | 6 | 3rd trimester |
| 30 | Month 7 | 6 | 3rd trimester |
| 31 | Month 8 | 7 | 3rd trimester |
| 32 | Month 8 | 7 | 3rd trimester |
| 33 | Month 8 | 7 | 3rd trimester |
| 34 | Month 8 | 7 | 3rd trimester |
| 35 | Month 9 | 8 | 3rd trimester |
| 36 | Month 9 | 8 | 3rd trimester |
| 37 | Month 9 | 8 | 3rd trimester |
| 38 | Month 9 | 8 | 3rd trimester |
| 39 | Month 9 | 8 | 3rd trimester |
| 40 | Month 9 | 9 | 3rd trimester |

Conversion at 4.345 weeks per month.

## How to convert weeks to months

```
Months = weeks ÷ 4.345
Current month = whole number of Months + 1
```
Example: 24 weeks ÷ 4.345 = 5.52. That is 5 completed months and the 6th month underway.

Many people use 4 weeks per month, which leaves out about 4 weeks of pregnancy: 9 × 4 = 36, and a full pregnancy is 40. A calendar month runs 4 to 4.5 weeks, so the right math uses the 4.345 average.

> Doctors speak in weeks because weeks are more precise. Months are a rough way to talk about pregnancy with friends and family.

Not sure how far along you are? Use the [due date calculator](https://www.calterix.com/en-us/calculator/due-date/) with your last period or ultrasound results.

## Frequently asked questions

### How many months is a 40 week pregnancy?

About 9 months and 1 week. A full pregnancy is 40 weeks, and a month averages 4.345 weeks.

### How many months is 20 weeks pregnant?

20 weeks is 4 months and 3 weeks, so you are in month 5 and about halfway through the pregnancy.

### How many months pregnant am I at 12 weeks?

At 12 weeks you are almost 3 months along, in month 3, at the end of the 1st trimester.

### When is a baby considered full term in months?

Full term starts at 39 weeks, about 9 months. Early term begins at 37 weeks, a little over 8 months.