Implantation Calculator
Implantation happens 6 to 12 days after ovulation — most often on days 8–10. See your exact day-by-day window and the earliest date a pregnancy test becomes reliable.
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Your 40-week timeline
Heartbeat ~8w
Anatomy scan ~20w
Full term 39w
You
1st trimester2nd trimester3rd trimester
Week 1Week 13Week 27Due · 40
Based on Naegele's rule (ACOG methodology). Estimates only — always confirm with your provider.
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How the implantation window works
After fertilization, the embryo travels down the fallopian tube for several days before attaching to the uterine lining — that attachment is implantation. Research on confirmed pregnancies shows it occurs 6–12 days past ovulation, with days 8–10 by far the most common. Only after implantation does your body start producing hCG, the hormone pregnancy tests detect — which is why testing too early gives false negatives even when you are pregnant.