How Long Does Ovulation Last?
The egg's lifespan, the sperm's head start, and the six-day window that actually matters.
Ovulation itself, the release of the egg, is a moment, and the egg survives only 12 to 24 hours afterward. But the fertile window spans about six days: the five days before ovulation plus ovulation day, because sperm can survive up to five days waiting for the egg. Timing in the 2-3 days before ovulation gives the best odds.
The egg: 12 to 24 hours
Ovulation is the moment a mature follicle releases the egg, and the egg remains viable for about 12 to 24 hours afterward. If no sperm is present in the fallopian tube during that window, the egg disintegrates and the cycle moves on. The event itself is brief; everything around it is preparation and aftermath.
This short lifespan is why timing feels so tight, and why methods that detect ovulation after the fact, like temperature rise, cannot guide timing for the current cycle. By the time you confirm it, the window is closing.
The sperm: up to 5 days
Sperm survive up to five days in fertile cervical mucus, the egg-white mucus produced in the days before ovulation. This head start is what stretches a one-day egg lifespan into a six-day fertile window: intercourse up to five days before ovulation can still result in conception.
Survival varies: without fertile mucus, sperm last hours to a day or two. With it, the full five days is possible. This is also why the days just before ovulation outperform ovulation day itself in conception odds; the sperm are already in position.
The fertile window, day by day
Label ovulation day as day 0. Days -5 through -1 carry rising odds as ovulation approaches; day -2 and day -1 are typically the peak conception-probability days in studies; day 0 is still fertile; day +1 onward drops to near zero as the egg expires.
In a 28-day cycle with ovulation on day 14, the fertile window is roughly days 9 through 14. In longer or shorter cycles, anchor on ovulation (14 days before the next period), not on day 14 from the last period.
What this means for timing
For conception, aim for the 2-3 days before expected ovulation rather than ovulation day itself. Every-other-day timing through the fertile window covers the bases without the stress of daily scheduling, and studies show no meaningful advantage to daily over every-other-day.
For avoiding pregnancy, remember the window shifts: stress, illness, and cycle variation move ovulation, and calendar math alone is not contraception. Use reliable contraception if pregnancy is not the goal.
Skip the arithmetic
Find your six-day window with the free ovulation calculator.
Ovulation timing questions
How long does the egg live after ovulation?
About 12 to 24 hours after release. If sperm is not present in the fallopian tube during that time, fertilization cannot occur and the egg disintegrates. This short viability is why the days before ovulation matter more than the day after.
How many days is a woman fertile each month?
About six days per cycle: the five days before ovulation plus ovulation day itself. The egg lives only 12 to 24 hours, but sperm can survive up to five days in fertile cervical mucus, which extends the fertile window backward from ovulation day.
What are the best days to conceive?
The two to three days before expected ovulation typically show the highest conception probability in studies, because sperm deposited then are waiting when the egg releases. Every-other-day timing through the fertile window performs about as well as daily timing.