Pregnancy & Due Date Calculator

Calculate your expected due date and fetal age in weeks and days, and follow weekly development from week 4 to week 40. Free tool running entirely in your browser for complete privacy.

First Day of Last Period

Cycle Length days

Expected Due Date

Pregnancy Progress

Expected Due Date

Current Gestational Age weeks, days

Trimester

Estimated Conception Date

Days Until Due Date

Live Birth Countdown

Days

Hours

Minutes

Seconds

Baby's Size This Week Week

Key Features

Instant in-browser calculations

We use Naegele's Rule — the medically accepted standard — to calculate your estimated due date with precision.

Complete privacy — no data sent to any server

All calculations run entirely in your browser. No health data is ever sent to our servers.

Weekly fetal development tracking

Get detailed weekly insights on fetal development, body changes, and tips from Week 4 to Week 40.

Live countdown timer to your due date

Use your Last Menstrual Period date or your Expected Due Date — whichever you know.

Why Use Our Calculator?

Medically Accurate (Naegele's Rule)

We use Naegele's Rule — the medically accepted standard — to calculate your estimated due date with precision.

Absolute Privacy

All calculations run entirely in your browser. No health data is ever sent to our servers.

Weekly Milestone Details

Get detailed weekly insights on fetal development, body changes, and tips from Week 4 to Week 40.

Two Calculation Methods

Use your Last Menstrual Period date or your Expected Due Date — whichever you know.

How to Use

Choose Your Method

Select whether you know your last period date or your expected due date.

Enter the Date

Enter the relevant date and your cycle length if using the LMP method.

View Your Results

Instantly see your due date, gestational age, trimester, and weekly developmental details.

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FAQ

The due date is calculated using Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period. If your cycle is longer or shorter than 28 days, the calculation is adjusted accordingly.

Yes, all calculations happen entirely in your browser. No data is transmitted to our servers. Your health information stays exclusively on your device.

The estimated due date is a medically accepted estimate but not a guaranteed date. About 95% of babies are born within two weeks of the predicted date. Confirm with your doctor via ultrasound for the most accurate dating.

The first trimester is weeks 1–13, the second is weeks 14–26, and the third is weeks 27–40. Each trimester brings distinct fetal developmental milestones and changes in the mother's body.

Gestational age is counted from the first day of your last period, while fetal age (actual embryo age) is typically about two weeks less. Doctors use gestational age as the standard measurement.

Track Your Pregnancy Week by Week

Use our free, privacy-first pregnancy calculator to know your due date and follow your baby's development every week.

Calculate Now