Pregnancy Due Date

About the Pregnancy Due Date

Finding out roughly when your baby is due is one of the first and most exciting moments of pregnancy. The standard estimate counts 40 weeks from the first day of your last menstrual period, which is how midwives and doctors date a pregnancy.

This Pregnancy Due Date calculator estimates your due date and current pregnancy week from your last period, giving you a timeline to plan around. It is an estimate — only a small fraction of babies arrive exactly on the due date.

How to use the Pregnancy Due Date

1. Enter the first day of your last menstrual period.
2. Adjust your average cycle length if it differs from 28 days.
3. The tool counts 40 weeks forward.
4. See your estimated due date and current week.

Key features of the Pregnancy Due Date

• Estimates your due date (40-week method)
• Shows your current pregnancy week
• Adjusts for your cycle length
• A timeline for planning ahead
• Private — calculated in your browser

How the Pregnancy Due Date works

This calculator applies standard, peer-reviewed formulas used by health professionals and public-health bodies worldwide. Depending on the metric, that includes the World Health Organization (WHO) classification, NHS and CDC guidance, the Mifflin-St Jeor equation for metabolic rate, and the U.S. Navy method for body composition. Inputs are converted between metric and imperial units using exact factors so results are consistent whichever system you use.

All calculations are performed in your browser, so the health information you enter is never sent anywhere.

Tips & best practices

• The due date is an estimate — most babies arrive in the two weeks either side of it, not exactly on the day.
• An early ultrasound often gives a more precise date than the last-period method, so your provider may adjust it.
• If your cycle is longer or shorter than 28 days, enter your actual length for a better estimate.

Standards & accuracy

Uses internationally recognised clinical formulas — WHO, NHS, CDC, the U.S. Navy method and Mifflin-St Jeor — for screening-grade estimates.

Important: these tools provide screening-grade estimates for general information and education only. They are not a medical diagnosis and do not replace professional advice. Always consult a qualified healthcare provider before making health decisions.

Who uses the Pregnancy Due Date?

• Getting an estimated due date early on
• Tracking which week of pregnancy you are in
• Planning appointments and leave
• Following your pregnancy timeline

Privacy & security

The Pregnancy Due Date runs entirely inside your web browser. Your data — whether that is a file, figures or text — is processed on your own device and is never uploaded to a server, stored or shared. There is no signup and no account, so you can use it as often as you like while keeping full control of your information. This makes it a safe choice even for confidential and sensitive work.

Why choose Toolinza?

• 100% free — no hidden charges, watermarks or usage caps.
• Private & secure — your data stays on your device.
• Standards-compliant — accurate results suitable for the UK, USA, Canada, Australia, EU, India, Pakistan, the Middle East and worldwide.
• Works everywhere — desktop, tablet and mobile.

Frequently asked questions