Free tool

Pregnancy Trimester Calculator

Enter your last menstrual period or due date to find out which trimester you're in and see the exact calendar date ranges for all three trimesters.

Enter a date to see your trimester breakdown.

How to use this calculator

Choose your input method — either the first day of your last menstrual period (LMP) or your estimated due date (EDD) — then enter the date. The calculator shows your current trimester, current week and day, and the calendar date range for each of the three trimesters, with your current trimester highlighted.

Understanding your result

Pregnancy is divided into three trimesters as a convenient way to track development and plan care. Trimester 1 (weeks 1–13) covers early development and includes the period most associated with morning sickness. Trimester 2 (weeks 14–27) is often when energy returns and the bump becomes visible. Trimester 3 (weeks 28–40) is the final stretch leading to birth. The trimester dates shown are calculated from your LMP-equivalent start date, following the standard 280-day (40-week) model.

Disclaimer

Menstrual cycles, fertility, and pregnancy vary significantly between individuals. Results from this tool are statistical estimates and may not reflect your personal health. This is not medical advice, a diagnosis, or a substitute for professional care. If you have concerns about your pregnancy or reproductive health, consult a gynaecologist or healthcare provider.

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Frequently asked questions

When does each trimester start and end?

Trimester 1 covers gestational weeks 1–13 (from your last menstrual period through early pregnancy). Trimester 2 covers weeks 14–27, often called the "middle trimester." Trimester 3 covers weeks 28 through birth, typically around week 40. This calculator shows you the calendar dates for each trimester based on your LMP or due date.

Is this medical advice?

No. This calculator provides estimates for informational purposes only. Always consult a qualified healthcare professional before making decisions about your health.

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