Pregnancy Due Date Calculator
Estimate your baby's due date and current week of pregnancy from your last period or conception date with this free calculator in your browser.
Enter details
Result
Enter a date to see your estimate.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified 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
- Ovulation Calculator
- Conception Date Calculator
- Period Calculator
- Nights in Care Calculator
- Pocket Money Savings Calculator
- Care Percentage Calculator
Explore more in Family, Parenting & Custody.
Cite this tool
Zerdly. (2026). Pregnancy Due Date Calculator. Retrieved from https://www.zerdly.com/tools/pregnancy-due-date-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.