Pregnancy Calculator

Enter the first day of your last menstrual period (or your conception date, due date, or ultrasound date) to get your estimated due date, current gestational age, and key pregnancy milestones. Choose your calculation method, adjust your average cycle length if needed, and your full pregnancy timeline renders right away.

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

Enter the first day of your last period.

days

Most cycles are 28 days. Adjust if yours differs.

The approximate date of conception.

Enter your due date if you already know it.

The date your ultrasound was performed.

weeks

Weeks shown on your ultrasound report.

days

Additional days beyond full weeks (0–6).

Results

Estimated Due Date

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Current Gestational Age

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Current Trimester

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Weeks Remaining

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Estimated Conception Date

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End of 1st Trimester

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End of 2nd Trimester

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Results Table

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Frequently Asked Questions

What is an estimated due date (EDD)?

Your estimated due date is the approximate date your baby is expected to be born, typically 40 weeks from the first day of your last menstrual period. It's an estimate — only about 4% of babies are born exactly on their due date. Most births happen within two weeks before or after the EDD.

How is my due date calculated?

The most common method uses Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period, adjusted for your cycle length. Alternatively, your due date can be estimated from your conception date (add 266 days), an ultrasound measurement, or a known due date entered in reverse.

How accurate is my estimated due date?

Due dates are estimates, not guarantees. Early ultrasounds (before 13 weeks) are generally the most accurate method. Calculations based on the last menstrual period assume a regular 28-day cycle, so if your cycle varies, your actual due date may differ. Your doctor may revise the date as your pregnancy progresses.

Can my due date change after it's been set?

Yes. Your healthcare provider may adjust your due date based on ultrasound findings, especially in the first trimester. A significant difference between the ultrasound measurement and your LMP-based date can lead to a revised EDD. Later ultrasounds are less accurate for dating.

What if I already know my due date?

Select 'Due Date' as your calculation method and enter your known due date. The calculator will work backwards to estimate your conception date, last menstrual period, and current gestational age, and will display your pregnancy milestones going forward.

How many weeks is a full-term pregnancy?

The World Health Organization defines a normal pregnancy as lasting between 37 and 42 weeks. A full-term birth is typically considered to occur between 39 and 40 weeks and 6 days. Births before 37 weeks are considered preterm, while those after 42 weeks are post-term.

How can I tell how far along I am in my pregnancy?

Gestational age is measured in weeks and days from the first day of your last menstrual period. For example, if 10 weeks have passed since your LMP, you are 10 weeks pregnant. An ultrasound can confirm gestational age by measuring the baby's size.

Can I plan or choose my due date?

While you cannot choose the exact day your baby arrives, knowing your estimated due date helps you plan prenatal care, maternity leave, and baby preparations. If you're considering fertility treatments or have a planned C-section, your medical team will work with you on timing.