worldofcalcsConception Calculator
Estimated Conception Date
Sun Dec 14 2025
Likely Range: Fri Dec 12 2025 - Tue Dec 16 2025
Estimated Due Date
Sun Sep 06 2026
About Conception Dates
Conception usually occurs about 11-21 days after the first day of your last period. Sperm can live inside the body for up to 5 days, so intercourse a few days before ovulation can also lead to conception.
Calculation Methods
- By Due Date: Subtracts 266 days (38 weeks) from the due date.
- By Last Period: Adds 14 days to the start of the last period (assuming a 28-day cycle).
Note
This is an estimate. Ultrasound scans are the most accurate way to date a pregnancy.