Pregnancy Week Calculator

Find your current gestational week, trimester, due date, and weekly milestone — week by week.

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Enter your last menstrual period date to see your current pregnancy week

How gestational age is calculated

Gestational age is counted from the first day of your last menstrual period (LMP), not from conception. This is because ovulation and conception are harder to pinpoint precisely, while the LMP date is easier to recall.

From LMP
Gestational age = today − LMP (in days)
Due date = LMP + 280 days (40 weeks). Example: LMP = 1 January 2025 → EDD = 8 October 2025.
From Conception Date
LMP ≈ Conception date − 14 days
Conception typically occurs 14 days after LMP in a 28-day cycle, so LMP is estimated by subtracting 14 days from conception date.

Frequently asked questions

How do I know what week of pregnancy I am in?

Count the number of days from the first day of your last menstrual period (LMP) to today, then divide by 7. The whole number is your completed weeks. For example, 70 days from LMP = 10 weeks pregnant. This calculator does this automatically and also shows days within the current week.

What are the three trimesters of pregnancy?

The first trimester covers weeks 1–13 (organ formation, highest miscarriage risk). The second trimester covers weeks 14–27 (foetal movement felt, anatomy scan at 18–20 weeks). The third trimester covers weeks 28–40+ (rapid growth, lungs maturing, preparation for birth).

When is a pregnancy considered full term in India?

A pregnancy is considered full term between 39 and 40 weeks. Early term is 37–38 weeks, late term is 41 weeks, and post-term is 42+ weeks. Indian hospitals and gynaecologists typically aim for delivery between 39–41 weeks unless complications arise.

Is the due date calculated from LMP or conception?

Medically, the due date (EDD) is calculated from LMP using Naegele's rule: LMP + 280 days. If you know your conception date, LMP is estimated as conception minus 14 days. An early dating ultrasound (before 12 weeks) is the most accurate way to confirm your due date.

What if my cycle is not 28 days?

The LMP-based calculation assumes a 28-day cycle with ovulation on day 14. If your cycle is longer (e.g., 35 days), add the extra days to the EDD. If shorter (e.g., 21 days), subtract. An early ultrasound removes this uncertainty and is recommended for all pregnancies regardless of cycle regularity.