Pregnancy Due Date Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter details
Result
Enter a date to see your estimate.
Estimate only — not medical advice. Due dates, ovulation and fertile windows vary between people and cycles. Confirm with a healthcare professional.
How to use this calculator
- Choose to calculate from your last period, conception date or IVF transfer.
- Enter the date.
- Read the estimated due date, how far along you are and the trimester.
How it works
From the last menstrual period the due date is LMP + 280 days (Naegele's rule). Conception adds 266 days; IVF uses the transfer date and embryo age.
Worked example
LMP 1 Jan 2026. Estimated due date ≈ 8 Oct 2026.
Tips
- Estimate only — not medical advice. Dates and fertile windows vary between people and cycles; confirm with a healthcare professional.
Frequently asked questions
How accurate is a due date?
Only about 1 in 20 babies arrive on the exact date — it's an estimate; a scan gives a better one.
Is my data uploaded?
Runs entirely in your browser. Your inputs are not saved or transmitted.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.