Pregnancy Due Date

How to use Pregnancy Due Date

1. Open Pregnancy Due Date in your browser — it loads instantly and works offline once cached.
2. Enter your values in the input fields. Every field is labelled so you know exactly what to type.
3. The result updates automatically as you type — there is no "submit" round-trip to a server.
4. Adjust any input to compare scenarios and see how the outcome changes in real time.
5. Copy or note the result. Nothing you enter is stored or sent anywhere.

Why use Pregnancy Due Date?

• 100% free with no limits, no sign-up and no watermarks.
• Private by design — your data are processed in your browser and never uploaded to a server.
• Fast and lightweight, with instant results even on a phone or a slow connection.
• Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
• Part of a full health & fitness suite, so related due date tasks are one click away.

What people use Pregnancy Due Date for

• Estimating a due date from the last menstrual period.
• Working out how many weeks pregnant you are.
• Planning appointments and leave around an estimated date.

Pregnancy Due Date: limits and things worth knowing

• Naegele's rule adds 280 days (40 weeks) to the first day of the last menstrual period, assuming a regular 28-day cycle with ovulation on day 14.
• Only about 4% of births occur on the estimated date, and a birth is considered full term anywhere from 37 to 42 weeks. The date is a midpoint, not a deadline.
• Irregular cycles make LMP-based dating unreliable. An early ultrasound is substantially more accurate and is what clinicians use to date a pregnancy.
• Pregnancy is conventionally counted from the last period, roughly two weeks before conception, which is why 'weeks pregnant' exceeds time since conception.
• General information only. Your midwife or doctor's dating takes precedence over any calculator.

Is it private and secure?

Your privacy is built in. Pregnancy Due Date runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.

Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.

You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.

Learn more

Why Browser-Based Tools Are Safer for Your Files — Most online converters upload your files to a server. Client-side tools don't. Here's why that difference matters for privacy.