ToolsConception Calculator
Women's health & pregnancy
Conception Calculator
Curious when conception likely happened? Working back from your last period or your due date gives a close-enough window.
Want to know what this means for you?Ask Seri
Part of Seri Bloom, one of Seri's health companions.
How it's calculated
From your last period, we add about 14 days to reach likely ovulation. From a due date, we count back 266 days. Either way we show a short window rather than a single day.
How to read your result
Conception timing is an estimate built on a typical cycle, so the window matters more than the exact date. If your cycle is longer or shorter than average, ovulation, and conception, shifts with it.
Common questions
It is an estimate. Even with a known last period, ovulation varies, so a window of a few days is more honest than a single date.
Method: Estimated from cycle dates (14-day ovulation).