Pregnancy Week Calculator
Find out how many weeks pregnant you are and what trimester you're in based on your last menstrual period.
You Are
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Trimester
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Days Pregnant
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Estimated Due Date
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Days Until Due Date
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Progress
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How to Use the Pregnancy Week Calculator
- Enter your LMP: Provide the first day of your last menstrual period.
- Adjust cycle length: Enter your average cycle length if different from 28 days.
- View your results: See your current week, trimester, due date, and progress.
Trimester Breakdown
| Trimester | Weeks | Key Developments |
|---|---|---|
| First | 1 - 12 | Organ formation, heartbeat begins |
| Second | 13 - 26 | Movement felt, gender visible on ultrasound |
| Third | 27 - 40 | Rapid growth, lung maturity, birth preparation |
Frequently Asked Questions
How are pregnancy weeks counted?
Pregnancy weeks are counted from the first day of your last menstrual period (LMP), not from conception. This means you are already considered "2 weeks pregnant" at the time of conception.
How long is a full-term pregnancy?
A full-term pregnancy is 39-40 weeks. Babies born between 37-38 weeks are considered early term, and those born after 42 weeks are post-term.