39 weeks in months: how far along you are
39 weeks pregnant is month 9 of pregnancy, in the third trimester. In calendar terms, 39 weeks is about 9.0 calendar months (almost 9 months). You’re 98% of the way to a 40-week due date, with 1 week to go.
A calendar calculation, not medical advice. Your provider’s dating ultrasound is the reference for your due date. Nothing you type leaves this page.
39 weeks at a glance
| Measure | At 39 weeks |
|---|---|
| Pregnancy month | Month 9 (weeks 36–40) |
| Trimester | Third |
| Calendar months | 9.0 (almost 9 months) |
| Counting 4-week months | 9.8 |
| Days pregnant | 273 |
| Weeks left until 40 | 1 |
Why some charts say 39 weeks is 9 months and others say 8
Pregnancy months are counted in two ways. Most US pregnancy charts group the 40 weeks into nine “pregnancy months” of four or five weeks each, which puts week 39 in month 9. A calendar month is about 4.35 weeks (30.44 days), so 39 weeks of calendar time is 9.0 months. Both answers are correct for what they measure; your provider will track the pregnancy in weeks.
What’s usually on the calendar around week 39
- You’re in the third trimester, which starts at week 28. (source)
- From week 36 until delivery, visits are usually weekly. (source)
- Testing for group B strep is routine from week 36. (source)
- Early term runs from 37 weeks through 38 weeks and 6 days. Full term runs from 39 weeks through 40 weeks and 6 days. (source)
Every pregnancy is different, and your provider’s schedule comes first.
Weeks around week 39
| Week | Pregnancy month | Calendar months | Trimester |
|---|---|---|---|
| 37 weeks | Month 9 | 8.5 | Third |
| 38 weeks | Month 9 | 8.7 | Third |
| 39 weeks | Month 9 | 9.0 | Third |
| 40 weeks | Month 9 | 9.2 | Third |
| 41 weeks | Past 40 weeks | 9.4 | Third |
See every week from 1 to 42 on the pregnancy weeks to months chart.
Questions
How many months is 39 weeks?
About 9.0 calendar months, or month 9 on a standard pregnancy chart.
Is 39 weeks pregnant 9 months?
On a standard pregnancy chart, yes: week 39 falls in month 9. In calendar time it’s 9.0 months, so counting only finished calendar months gives 8.
How do you convert 39 weeks to months?
Divide the days by the average calendar month: 39 × 7 = 273 days, and 273 ÷ 30.44 = 9.0 months (almost 9 months). On a pregnancy chart, week 39 is month 9.
How many days is 39 weeks pregnant?
273 days, counted from the first day of your last menstrual period.
What trimester is 39 weeks?
The third trimester.
39 weeks is how many months on a calendar?
39 weeks in months is about 9.0 calendar months. Counted in 4-week blocks instead, it’s 9.8.
Track every week on paper
The printable pregnancy planner has this chart, trimester calendars, an appointment log and a 40-week countdown.
Sources
- ACOG, “How Your Fetus Grows During Pregnancy”
- Cleveland Clinic, “Your Prenatal Appointment Schedule”
- NICHD, “Know Your Terms”
This page explains calendar math. It isn’t medical advice; ask your provider about your own pregnancy.