About the Pregnancy Due Date Calculator
Estimate your due date from the first day of your last period. This tool is free, works in your browser and needs no sign-up.
How to use the Pregnancy Due Date Calculator
Pick the first day of your last menstrual period. The tool shows the due date and how far along you are. Only a doctor can confirm a due date.
Formula used
Due date = first day of last period + 280 days.
Example
A last period starting on 1 January 2026 gives a due date of 8 October 2026.
Frequently asked questions
Is the Pregnancy Due Date Calculator free to use?
Yes. It is completely free and you can use it as many times as you like.
How accurate is the Pregnancy Due Date Calculator?
The calculator uses standard formulas, so the maths is exact. Real life results can differ because of fees, taxes, rounding or personal factors, so treat the answer as an estimate.
Do you store the numbers I enter?
No. All calculations run in your browser. The values you type are not sent to our server.
Disclaimer: results are estimates for information only. They are not financial, medical or professional advice.