Conception Date Calculator
Estimate a conception date from a known due date or the first day of the last period.
Your estimated dates will appear here.
Estimated conception date
- Possible fertile window
- Estimated due date
- Estimated last period
In this calculator, “estimated conception date” means an estimated fertilization date. It cannot identify the exact day fertilization, implantation, or intercourse occurred and cannot establish paternity. Last-period estimates assume ovulation around cycle day 14; actual timing varies.