Trimester Calculator
See the exact date range for each trimester, which one you're in now, and what to expect.
About this calculator
Enter your last menstrual period to see the calculated date range for all three trimesters, which one is currently active, how many days remain in it, and a brief summary of what's generally expected during that stage. Trimester boundaries here follow the standard convention used in prenatal care (first trimester through 13 weeks 6 days, second through 27 weeks 6 days, third from 28 weeks onward).
Frequently asked questions
- Do all providers use the same trimester boundaries?
- The boundaries used here (13w6d and 27w6d) are the standard convention, but you may occasionally see slightly different week cutoffs used informally — the differences are minor and don't affect the overall picture of your pregnancy's progress.
- Is what happens in each trimester the same for everyone?
- No — the summaries here describe general, commonly-reported experiences. Every pregnancy is different, and this isn't a substitute for guidance from your own healthcare provider.
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🔒 All calculations run entirely in your browser — nothing you enter is ever sent anywhere. These are estimates based on standard averages, not medical advice — consult your healthcare provider for guidance specific to you.