Implantation calculator: the 6 to 12 day window after ovulation

Implantation window for an estimated ovulation of Thu, Jan 15, 2026worked example

Fri, Jan 23, 2026 - Sun, Jan 25, 2026

Full observed window: Wed, Jan 21, 2026 to Tue, Jan 27, 20266 to 12 days past ovulation
Days past ovulation shown above: 8-10 DPO84% of the pregnancies in the study
Estimated ovulation: Thu, Jan 15, 2026

Wilcox, Baird and Weinberg dated implantation in 189 pregnancies by the first appearance of chorionic gonadotropin in daily urine samples. It happened between 6 and 12 days after ovulation, and 84% of it on day 8, 9 or 10. Your ovulation date is itself an estimate, so this window sits on top of that one.

What are you counting from?

Ovulation dateA positive ovulation test, a temperature shift, or a clinic scan date.

Everything you type here is computed in your browser. Nothing you enter is stored on a server, sent anywhere, or shared — there is no account and no health data to leak.

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Day by day past ovulation
Days past ovulation	Date	What the study found
6 DPO	Wed, Jan 21, 2026	Observed, less common
7 DPO	Thu, Jan 22, 2026	Observed, less common
8 DPO	Fri, Jan 23, 2026	In the 84% group
9 DPO	Sat, Jan 24, 2026	In the 84% group
10 DPO	Sun, Jan 25, 2026	In the 84% group
11 DPO	Mon, Jan 26, 2026	Observed, less common
12 DPO	Tue, Jan 27, 2026	Observed, less common

Wilcox, Baird and Weinberg, New England Journal of Medicine 1999. Implantation was dated by the first appearance of chorionic gonadotropin in daily urine samples, which is why the window can be this specific and why nothing here describes a symptom.

Things worth asking, and one thing worth knowing

Chorionic gonadotropin only starts rising at implantation, so a test taken before this window has nothing to find yet. After it, whether a test picks anything up depends on the sensitivity of that specific test.
We do not print an earliest test date here, because doing so would mean inventing a number that depends on your test, your rate of rise and your own body.
If you are bleeding, in pain, or something feels wrong, please contact your clinician or an early pregnancy unit rather than a calculator. This page cannot see you.

The sources this defers to

NHS: trying to get pregnant — the NHS view of ovulation timing and what actually helps
ACOG: Fertility Awareness-Based Methods of Family Planning — the fertile window this one follows on from

If you have two hCG results from a clinic, the hCG doubling time calculator does the arithmetic between them - also ad-free. To re-check the ovulation date this window is built on, see the ovulation calculator.

An implantation calculator dates the window in which a pregnancy implants, from your estimated ovulation date. Wilcox and colleagues measured this directly in 1999: implantation happened 6 to 12 days after ovulation, and 84 percent of it on days 8, 9 or 10. This page carries no ads.

Implantation window after ovulation — implantation occurred 6 to 12 days after ovulation; 84% on day 8, 9 or 10. Verified 2026-07-30 against Wilcox, Baird and Weinberg, N Engl J Med 1999 (Implantation was dated by the first appearance of chorionic gonadotropin in daily urine samples, in 189 pregnancies. It is a hormone measurement, not a sensation, and the study reports nothing about symptoms.)
Estimated ovulation day, anchored to the luteal phaseconvention — ovulation day of cycle = cycle length - 14. Verified 2026-07-30 against ACOG, Fertility Awareness-Based Methods of Family Planning (patient FAQ) (Counted back from the next expected period rather than forward from the last one, because the follicular phase is what varies. The NHS puts ovulation at 10 to 16 days before the next period, and Bull 2019 measured a mean luteal phase of 12.4 days with a 95% interval of 7 to 17 days, so this is a midpoint of a week-wide window.)
Real-world cycle and luteal phase variation — mean cycle 29.3 days; 13% of cycles exactly 28 days; mean luteal phase 12.4 days (95% CI 7-17). Verified 2026-07-30 against Bull et al., npj Digital Medicine 2019 (612,613 cycles from 124,648 users of a fertility app, so the population self-selects towards people tracking closely. The direction of the finding -- that the textbook 28-day cycle is a minority -- is not in doubt.)

Everything you type here is computed in your browser. Nothing you enter is stored on a server, sent anywhere, or shared — there is no account and no health data to leak.

No ads on this page, by design.

Frequently asked questions

How many days after ovulation does implantation happen?

Wilcox, Baird and Weinberg dated implantation by the first appearance of chorionic gonadotropin in daily urine samples across 189 pregnancies. It happened 6 to 12 days after ovulation, and 118 of the pregnancies - 84 percent - implanted on day 8, 9 or 10.

Can I feel implantation happening?

The study that dated implantation measured a hormone in urine, not a sensation, and reports nothing about symptoms. We are not going to list signs a paper did not find. If something is worrying you, a clinician can help in a way this page cannot.

When can a pregnancy test detect anything?

Chorionic gonadotropin only starts rising at implantation, so a test before then has nothing to find. After that it depends on the sensitivity of the specific test and on how fast the level rises, which is why this calculator deliberately does not print an earliest test date.

What does days past ovulation mean?

DPO counts from the estimated day of ovulation: 8 DPO is eight days after it. Because ovulation itself is estimated from your cycle length rather than measured, the DPO count inherits that uncertainty - a day or two either side is ordinary.

Why is this page ad-free?

Because of who reads it. People counting days past ovulation are often anxious, and some are in the middle of bad news. Serving ads next to that is not something we would be able to defend, so a test in this repository fails the build if ads ever appear here.

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The next number

No body metric means much on its own. Here is what this one feeds into.

hCG doubling time calculatorIf you have two hCG values from a clinic, this is the arithmetic between them - also ad-free.Due date calculatorThe dating convention, from the same ovulation date.

Related calculators

Ovulation calculatorCycle and ovulation hCG doubling time calculatorEarly pregnancy Conception date calculatorEarly pregnancy

Every formula on this page is listed with its source on the methodology page, and changes to any reference value are logged in the data changelog. Canonical URL: https://myhealthmywellness.com/implantation-calculator