Due Date Calculator

Estimate due date and gestational week.

Runs locallyNo signupMobile readyCopyableFree

🤰Due Date Calculator

All processing happens locally

First day of last period

Due date and week

Due Date Calculator is a pregnancy timeline estimator, calculations run on your device, so amounts and personal figures are never uploaded.

Results update instantly when you change a value; copy them for your records.

Paste or type your content into the input field at the top, or press the sample button to load demo data.
Adjust the options below the input, such as output format, separators, letter case or precision.
Press the main button to run the conversion. Results appear instantly in the output panel without a page reload.
When the result looks right, use the copy button in the corner, or download it as a local file.

Clean up stray spaces and line breaks before pasting for more accurate results.

Is the due date exact?+

No. Only about five percent of babies arrive on the date; two weeks either side is normal.

How are weeks counted?+

From the first day of the last period, seven days per week; 37 completed weeks counts as term.

Is Due Date Calculator free to use?+

Yes. The tool is completely free with no usage limits, and you never need an account or a sign-in.

Is the text I enter uploaded anywhere?+

No. All processing runs locally in your browser, so the input never reaches a server and is never logged or stored.

Does Due Date Calculator work on a phone or tablet?+

Yes. The layout is mobile-first, so inputs and buttons stay comfortable on phones and tablets in both orientations.

Can I copy the result into my own document?+

Yes. A copy button in the output panel puts the result on your clipboard, and you can also download it as a text file.