DPO Calculator
Work out how many days past ovulation you are, when implantation is likely, and when a pregnancy test is worth taking.
Your timeline
| DPO | Date | What happens |
|---|---|---|
| 6 | Saturday, October 31, 2026 | Earliest implantationIn the landmark study, implantation was first seen 6 days after ovulation. |
| 8 | Monday, November 2, 2026 | Most implantations (8–10 DPO)84% of implantations happen 8, 9 or 10 days after ovulation. |
| 12 | Friday, November 6, 2026 | Latest implantation in continuing pregnanciesPregnancies that continued had all implanted by 12 days after ovulation; later implantation was linked to early loss. |
| 14 | Sunday, November 8, 2026 | Expected periodEven a very sensitive lab test detects only about 90% of pregnancies by the first day of a missed period; home tests can be less sensitive. |
| 21 | Sunday, November 15, 2026 | A week after the expected periodAbout 97% of pregnancies are detectable by a very sensitive test by now. |
Ovulation here is estimated as 14 days before your next expected period. The real gap varies, so these dates could be several days off. An ovulation test gives a better date.
Medical disclaimer. This calculator is for general information and education only. It is not medical advice, not a diagnosis, and not a substitute for professional care. DPO dates are estimates built on averages from research, and a calculator cannot tell whether you are pregnant. A negative test before your period is due does not rule out pregnancy.Speak to a doctor or another qualified clinician about any health decision.Last reviewed .
Related: implantation calculator, ovulation calculator, due date calculator.
Why DPO is the clock that matters
Cycle day counts from the start of your period, but the second half of the cycle runs from ovulation. Implantation, the rise of the pregnancy hormone hCG and the next period all follow ovulation, not the period before it. That is why two people on cycle day 25 can be at very different points: one may be 11 DPO and the other only 4.
Implantation is the earliest point a test could ever turn positive, because hCG is only made once the embryo has implanted. In the study most of these figures come from, implantation in pregnancies that continued happened between 6 and 12 DPO, and most often on days 8 to 10. It then takes a few days for hCG to rise high enough for a home test to see.
So the most useful number is often the date your period is due. Testing from then on is far more reliable than testing at 8 or 9 DPO, when a negative tells you very little. If your period is late and the test stays negative, test again a few days later or speak to a clinician.
Frequently asked questions
What does DPO mean?
DPO stands for days past ovulation. The day you ovulate is 0 DPO, the next day is 1 DPO, and so on. People trying to conceive use it to time pregnancy tests, because implantation and the hormone a test detects both follow ovulation on a fairly predictable schedule.
How do I know when I ovulated?
The most direct home method is a urine ovulation (LH) test: ovulation usually follows the LH surge by about a day to a day and a half, so this calculator takes the day after your first positive test. A sustained rise in basal body temperature confirms ovulation after it has happened. Counting 14 days back from your next expected period is the least precise, because the second half of the cycle varies between people and between cycles.
When does implantation happen?
In the landmark study by Wilcox and colleagues (New England Journal of Medicine, 1999), implantation in pregnancies that continued happened 6 to 12 days after ovulation, and 84% happened on day 8, 9 or 10. Later implantation was linked to a higher chance of early loss.
How many DPO can I get a positive pregnancy test?
Not before implantation, because the pregnancy hormone hCG is only made after it. A positive is possible a few days after implantation, so some people test positive around 10 to 12 DPO, but many do not. In a study using a very sensitive lab test, about 90% of pregnancies were detectable on the first day of a missed period and 97% a week later (Wilcox and colleagues, JAMA, 2001). A negative before your period is due does not rule out pregnancy.
When is my period due?
Around 14 DPO on average, but the gap between ovulation and the next period varies. In one study of 141 women over 1,060 cycles, it averaged about 12 to 13 days, and 95% of cycles fell between 9 and 16 days (Fehring and colleagues, 2006). If you know your own usual luteal phase from tracking, trust that over the average.