Pregnancy Due Date Calculator — Free EDD & Pregnancy Week Calculator

Pregnancy Due Date Calculator — Free EDD & Pregnancy Week Calculator. Free pregnancy due date calculator. Enter your last period date and cycle length to get your estimated due date (EDD) and gestational weeks — 100% private, no account needed.

Our free pregnancy due date calculator estimates your Expected Delivery Date (EDD) based on the first day of your last menstrual period (LMP) using Naegele's Rule — the same clinical standard used by OB/GYNs worldwide.

Simply enter your LMP date and get an instant estimate of your baby's due date and your current gestational progress. How to Calculate Your Due Date Select the first day of your last menstrual period in the date field.

Enter your average cycle length in days (21 to 45, default 28). Your estimated due date (EDD) appears instantly — calculated as LMP + 280 days, plus the difference between your cycle length and 28 days.

The gestational progress cards show your current age in weeks and days, and total days elapsed. If the date is in the future, a message is shown instead.

How Due Date Calculation Works The standard formula (Naegele's Rule) adds 280 days — or 40 weeks — to the first day of your last menstrual period.

This assumes a 28-day cycle, so the calculator shifts the date by the difference: a 32-day cycle adds 4 days, a 25-day cycle subtracts 3 days.

Because most babies are born within two weeks of their EDD, this gives an accurate planning window for the vast majority of pregnancies.

Pregnancy Weeks & Trimesters First trimester : Weeks 1–12 Second trimester : Weeks 13–26 Third trimester : Weeks 27–40+ Privacy All calculations run 100% locally in your web browser.

Your LMP date and pregnancy information are never uploaded to any server — keeping sensitive personal health data completely private. Related Tools Track your health alongside your pregnancy with our BMI Calculator and BMR Calculator .

Frequently asked questions

How do I calculate my due date?

Pick the first day of your last period in the date field and, if it is not 28, enter your average cycle length in days. The Estimated Due Date appears immediately, along with Gestational Progress in weeks and days and the Total Gestational Days. A date in the future shows a message instead of progress.

How is the due date calculated?

It uses Naegele's rule: the first day of your last period plus 280 days, or 40 weeks, assuming a 28 day cycle. For a different average cycle length between 21 and 45 days, the date moves by the difference, so a 30 day cycle adds 2 days and a 26 day cycle subtracts 2 days.

How accurate is the estimated due date?

It is an estimate for planning, not a medical assessment. Few babies arrive on the exact date and most are born within about two weeks either side of it. An early ultrasound or your healthcare provider may give a different, more reliable date.

What does gestational age mean?

Gestational age is counted in whole calendar days from the first day of your last period, not from conception, so it is usually about two weeks more than the time since conception. With a cycle other than 28 days it is shifted by the same number of days as the due date.

Is my information stored or sent anywhere?

No. The date you enter is only used for the calculation in your browser; it is not sent to a server or saved in an account. Always confirm dates and pregnancy questions with a doctor or midwife.

How to use this online tool

Pregnancy Due Date Calculator — Free EDD & Pregnancy Week Calculator is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

Pregnancy Due Date Calculator — Free EDD & Pregnancy Week Calculator keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use Pregnancy Due Date Calculator — Free EDD & Pregnancy Week Calculator for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.