Implantation Calculator
Estimate the implantation window — typically 22 to 26 days after the first day of your last menstrual period.
What is Implantation?
After fertilisation, the embryo travels down the fallopian tube and implants in the uterine lining about 6–10 days post-ovulation. For a 28-day cycle this means around days 22–26 from the LMP. Implantation can be associated with light spotting and is the moment hCG starts rising — the hormone detected by pregnancy tests.
How is it calculated?
Implantation window ≈ LMP + 22–26 days. Earliest reliable hCG detection follows about 9–12 days after implantation.
Frequently Asked Questions
- Is implantation bleeding always present?
- No — most pregnancies have none.
- When can I take a pregnancy test?
- Most home tests are reliable from the day of expected period.
- Does implantation timing affect due date?
- Slightly — late implantation can mean a slightly later due date.