Implantation Calculator
Estimate when implantation may happen — from your last period, ovulation date or IVF transfer — with the most likely days, implantation bleeding timing and test dates.
When does implantation happen?
After an egg is fertilised it travels down the fallopian tube and attaches to the lining of the womb. In a large study that measured hormones every day, implantation happened 6 to 12 days after ovulation, and in most pregnancies (84%) on days 8, 9 or 10. The calculator uses these figures.
| Days after ovulation | What may happen |
|---|---|
| 0 | Ovulation; fertilisation within about 24 hours |
| 6–12 | Implantation window (most often 8–10) |
| Around implantation | Light spotting in some women (“implantation bleeding”) |
| 12–14+ | hCG may be high enough for a sensitive home test |
| 14 | Expected period — the most reliable day to test |
Implantation bleeding vs period
- Light pink or brown spotting, not bright red flow
- Lasts a few hours to 2 days
- Usually a few days before your period is due
- Mild cramping may happen; heavy bleeding or severe pain needs a doctor
Many women have no implantation symptoms at all — that is normal.
After IVF
A day-5 embryo (blastocyst) is already 5 days past fertilisation, so implantation often starts 1–5 days after transfer. Your clinic will tell you when to take the blood test (beta hCG), usually 9–14 days after transfer — follow their timing rather than testing early at home.
Next: see when to take a pregnancy test.
Frequently asked questions
How many days after ovulation does implantation occur?
Usually 6–12 days, most commonly 8–10 days after ovulation.
Can I feel implantation?
Some women notice light spotting or mild cramps, but most feel nothing. Symptoms alone cannot confirm pregnancy.
How soon after implantation can I test?
hCG starts rising after implantation and usually becomes detectable on a sensitive home test 2–4 days later. Testing on the day of your missed period is more reliable.
Sources: Time of implantation and loss of pregnancy (NEJM 1999) · Cleveland Clinic: Implantation bleeding
Reviewed for accuracy against the sources above. This page is general information, not medical advice — talk to your doctor or a registered dietitian about your own needs.