Implantation Calculator
Estimate the window when embryo implantation is most likely to occur, and find out when you might experience implantation spotting or when to take a pregnancy test.
Understanding Implantation Spotting
Approximately 1 in 3 women experience light spotting during implantation. This occurs when the blastocyst (fertilized egg) burrows into the rich lining of the endometrium, disrupting microscopic blood vessels.
Spotting vs. Period: Implantation spotting lasts a few hours to two days, does not require a tampon, and is pinkish-brown. A menstrual period is typically bright red and increases in flow.
The pregnancy hormone hCG is only produced after successful implantation.
We recommend waiting at least 3–4 days after the estimated most likely implantation day to take a home pregnancy test for optimal accuracy.