Pregnancy Trimester Calculator: Which Trimester Am I In?
Enter your last period or due date to see your current trimester and the dates of all three trimesters.
- Nothing you type is stored
- Free
- No signup
You are in trimester
1
1st trimester- Weeks pregnant
- 0 weeks
- Next trimester starts
- Wed, 10 Feb 2027
- Days left in this trimester
- 98 days
An estimate for general information, not medical advice. Dates can differ by a week or two; confirm with your doctor or ANM.
Trimester dates
| Trimester | Weeks | From | To |
|---|---|---|---|
| 1 | 1–13 | Wed, 4 Nov 2026 | Tue, 9 Feb 2027 |
| 2 | 14–27 | Wed, 10 Feb 2027 | Tue, 18 May 2027 |
| 3 | 28–40 | Wed, 19 May 2027 | Wed, 11 Aug 2027 |
How to use
- Choose last period or due date.
- Enter the date.
- See your trimester, when the next one starts and the dates of each trimester.
Good to know
Trimesters as defined by ACOG: 1st trimester from week 1 to 13 weeks 6 days, 2nd from 14 weeks 0 days to 27 weeks 6 days, 3rd from 28 weeks 0 days until birth (due date at 40 weeks).
The 1st trimester is when most organs form and nausea and tiredness are common. Many women feel better in the 2nd, when the anatomy scan (about 18–20 weeks) is done. The 3rd brings faster growth and more frequent check-ups.
Some books and apps split trimesters slightly differently (for example 1–12, 13–27). The dates here follow ACOG and are counted from your last period, so they are estimates; your doctor may adjust them after a scan.
Questions
When does the second trimester start?
At 14 weeks 0 days, counted from the first day of your last period.
When does the third trimester start?
At 28 weeks 0 days.
How long is each trimester?
About 13–14 weeks each; the third ends with birth, usually between 37 and 42 weeks.
Which months are in each trimester?
Roughly months 1–3 in the first, 4–6 in the second and 7–9 in the third.
Is my data saved?
No. Dates are calculated on your device and never sent anywhere.