How many days after ovulation does implantation happen?

That study measured a hormone, not a sensation. It collected daily urine samples and identified the first day chorionic gonadotropin appeared, which is why this site reports the window as a hormone finding and carries no list of implantation symptoms - the paper that dated implantation reports nothing about how it feels.

Every date the calculator produces is counted from an estimated ovulation day, so the window inherits that estimate's uncertainty on top of the study's. Unless ovulation was confirmed by testing or monitoring, it was calculated from your cycle length, and the published interval around that calculation is several days wide. A day or two either side of any DPO count is ordinary.

There is deliberately no earliest test date here. Chorionic gonadotropin only starts rising once implantation begins, so a test before then has nothing to detect; after that, detection depends on the sensitivity of the specific test and on how fast the level climbs. Home test sensitivities differ too much for a printed date to be meaningful for most readers.

The implantation page and the hCG doubling time calculator both carry no advertising, by policy and enforced by a test in this repository. People counting days past ovulation are often anxious, and some are in the middle of bad news.