Implantation Calculator

Implantation is when a fertilised egg embeds in the lining of the uterus — the moment pregnancy hormones begin to rise. Enter your last period and cycle length to estimate when it may happen and when a test could turn positive.

First day of your last periodAverage cycle length: 28 days

Estimates based on a regular cycle, for general information only — not medical advice or a diagnosis. Timing varies between people.

How it works

After ovulation, a fertilised egg takes about 6 to 12 days to reach and implant in the uterus, most often around days 8 to 10. Only after implantation does hCG start to rise, which is why testing makes sense a few days later. We estimate ovulation as roughly 14 days before your next period.

Frequently asked questions

When does implantation happen? +

Usually 6–12 days after ovulation, with days 8–10 being most common. We show that window based on your estimated ovulation day.

Is implantation bleeding real? +

Some people notice light spotting around implantation, but many don’t — and spotting can have other causes. It isn’t a reliable sign of pregnancy on its own.

Can I feel implantation symptoms? +

So-called implantation symptoms overlap closely with normal premenstrual changes, so they can’t confirm or rule out pregnancy. A test after your expected window is far more dependable.