Estimate

Conception Date Calculator

Estimate when you likely conceived based on your last period or your due date. Enter whichever date you know.

First day of your last menstrual period (LMP)

Your estimated due date (EDD)

Estimated Conception Date

—

💡 Conception typically occurs around day 14 of a 28-day cycle — about 2 weeks after your LMP. This is an estimate; the actual window can vary by several days depending on your cycle length.

Frequently Asked Questions

How accurate is a conception date estimate?

Conception date estimates are approximate. Ovulation typically occurs around day 14, but can range from day 11–21 depending on your cycle. Sperm can also survive up to 5 days, making pinpointing conception difficult without medical testing.

What's the difference between conception date and LMP?

Your LMP (last menstrual period) is the clinical start of pregnancy dating, but conception doesn't happen until about 2 weeks later when an egg is fertilized. So your "gestational age" is always about 2 weeks more than your "fetal age."

Can I find out the exact date of conception?

Not without close monitoring (like ovulation tracking or fertility treatment). For most people, the conception window is a range of 5–7 days rather than a single day.

Is this medical advice?

No — this tool is for informational purposes only. Always follow the guidance of your doctor or midwife.