Due Date Calculator
Calculate your pregnancy due date from the first day of your last menstrual period, plus your conception date and trimester milestones — free online. — free, fast and private.
How to use Due Date Calculator
- Choose the first day of your last menstrual period.
- Click Calculate Due Date to see your estimated due date.
- Use the result to plan prenatal appointments with your doctor.
Note: this tool runs in your browser. Nothing is uploaded.
Disclaimer: this is an estimator only — please see a qualified professional for advice about your specific situation. This is an estimate based on a regular 28-day cycle. Only a doctor or midwife, usually with an ultrasound, can confirm your due date. See a healthcare professional for prenatal care.
Frequently Asked Questions
How is a due date calculated from the last period?
Add 280 days (40 weeks) to the first day of your last menstrual period. Conception is usually assumed about 14 days after that date in a regular 28-day cycle. An early ultrasound gives a more accurate date.
Is this tool free to use?
Yes, it is 100% free with no sign-up. Your data stays in your browser.
Is my data uploaded or stored?
No. This tool runs entirely in your browser — nothing you enter is uploaded to a server.
Can I use it on my phone?
Yes, it is fully mobile-friendly and works in any modern browser on phone, tablet or computer.