Due Date and Gestational Age Today
Display both an estimated due date and today’s gestational age from the first day of the last period. This is not age from fertilisation; clinical dating may use ultrasound or embryo-transfer information.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
How to use this tool
Choose the LMP start date. The implementation rejects future dates and dates over 315 days ago, and offers neither cycle-length adjustment nor IVF-transfer inputs.
Results and examples
Due date is LMP plus 280 days; weeks and days are the quotient and remainder of elapsed days to today. Record the checking date with the result because today’s age changes over time.
Worked example
An LMP of 15 January 2026 gives a due date of 22 October; the age-today value depends on the date of use.
Limitations
- Ultrasound redating and cycle-length variation are not incorporated.
- Calendar arithmetic cannot assess pregnancy progress or wellbeing.
Fields
| Field | Guidance and constraints |
|---|---|
| First day of last period | Check the unit and format displayed beside this field. |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
Why did the age change since yesterday?
It recalculates elapsed time through today.
Should I enter conception date?
No. This method requires the first day of the last period.
Related tools
You do not need to start over. Continue with the tool that fits your next step.
