How many months is 13 weeks pregnant?
13 weeks pregnant is month 3 of pregnancy, in the first trimester. In calendar terms, 13 weeks is about 3.0 calendar months (almost 3 months). You’re 32% of the way to a 40-week due date, with 27 weeks 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.
13 weeks at a glance
| Measure | At 13 weeks |
|---|---|
| Pregnancy month | Month 3 (weeks 9–13) |
| Trimester | First |
| Calendar months | 3.0 (almost 3 months) |
| Counting 4-week months | 3.2 |
| Days pregnant | 91 |
| Weeks left until 40 | 27 |
Why some charts say 13 weeks is 3 months and others say 2
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 13 in month 3. A calendar month is about 4.35 weeks (30.44 days), so 13 weeks of calendar time is 3.0 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 13
- You’re in the first trimester, which runs through 13 weeks and 6 days. (source)
- In a healthy pregnancy, prenatal visits are usually about every four weeks until week 28. (source)
- NIPT, a blood test for genetic conditions, is typically available after 10 weeks. (source)
- The quad screen, a blood test, is offered between weeks 15 and 20. (source)
Every pregnancy is different, and your provider’s schedule comes first.
Weeks around week 13
| Week | Pregnancy month | Calendar months | Trimester |
|---|---|---|---|
| 11 weeks | Month 3 | 2.5 | First |
| 12 weeks | Month 3 | 2.8 | First |
| 13 weeks | Month 3 | 3.0 | First |
| 14 weeks | Month 4 | 3.2 | Second |
| 15 weeks | Month 4 | 3.4 | Second |
See every week from 1 to 42 on the pregnancy weeks to months chart.
Questions
Is 13 weeks pregnant 3 months?
On a standard pregnancy chart, yes: week 13 falls in month 3. In calendar time it’s 3.0 months, so counting only finished calendar months gives 2.
How do you convert 13 weeks to months?
Divide the days by the average calendar month: 13 × 7 = 91 days, and 91 ÷ 30.44 = 3.0 months (almost 3 months). On a pregnancy chart, week 13 is month 3.
How many days is 13 weeks pregnant?
91 days, counted from the first day of your last menstrual period.
What trimester is 13 weeks?
The first trimester.
13 weeks is how many months on a calendar?
13 weeks in months is about 3.0 calendar months. Counted in 4-week blocks instead, it’s 3.2.
Track every week on paper
The printable pregnancy journal gives you a page for every week from 4 to 40, and the pregnancy planner has this chart, trimester calendars and an appointment log.
Sources
- ACOG, “How Your Fetus Grows During Pregnancy”
- Cleveland Clinic, “Your Prenatal Appointment Schedule”
This page explains calendar math. It isn’t medical advice; ask your provider about your own pregnancy.