How Long Does Ovulation Last?
The answer might surprise you—and it's why timing is everything.
The Quick Answer
- Ovulation itself: The egg release takes just minutes
- Egg viability: 12-24 hours after release (that's it!)
- Sperm survival: Up to 5 days in fertile cervical mucus
- Your fertile window: ~6 days total (5 days before + ovulation day)
The Moment of Ovulation
Ovulation is actually a brief event—the physical release of the egg from the ovary takes just a few minutes. The follicle ruptures, and the egg is released into the fallopian tube. That's it.
But when people ask "how long does ovulation last," they usually mean one of two things:
- How long is the egg viable? (How long can it be fertilized?)
- How long is the fertile window? (When can I get pregnant?)
These are very different—and understanding both is key to conception.
How Long Does the Egg Survive?
Once released, the egg has a very short window for fertilization: 12-24 hours. Most experts lean toward the lower end—realistically, 12-18 hours is the prime window.
After that, the egg begins to degrade. If sperm doesn't reach and fertilize it within this window, pregnancy cannot occur from that egg.
🔬 Why So Short?
Unlike sperm (which can survive for days in the right environment), eggs are much more fragile. The egg's quality deteriorates quickly after release, and after about 24 hours, it's no longer viable for fertilization.
This Is Why Timing Is Everything
With only a 12-24 hour window for fertilization, you might think conception is difficult. But nature has a solution: sperm can wait.
Sperm deposited in the female reproductive tract can survive up to 5 days when fertile cervical mucus is present. This means sperm from sex 3-4 days before ovulation can still be there, ready and waiting, when the egg is released.
Your Full Fertile Window
When you combine egg viability with sperm survival, your fertile window is approximately 6 days:
- 5 days before ovulation: Sperm deposited on these days can survive until the egg arrives
- Ovulation day: The egg is released and can be fertilized for 12-24 hours
Your Fertile Window Timeline
O = Ovulation day. Percentages are approximate pregnancy rates per cycle for healthy couples.
⚠️ After Ovulation = Too Late
Once ovulation has occurred and 24 hours have passed, your fertile window is closed for that cycle. Sex after this point cannot result in pregnancy. This is why predicting ovulation in advance (with OPKs, CM tracking, etc.) is so important.
Best Days to Have Sex
Research consistently shows that the highest pregnancy rates come from sex in the 2-3 days before ovulation:
| Day Relative to Ovulation | Pregnancy Rate | Notes |
|---|---|---|
| O-5 (5 days before) | ~4-5% | Possible but unlikely |
| O-4 (4 days before) | ~10% | Low but viable |
| O-3 (3 days before) | ~15% | Moderate chance |
| O-2 (2 days before) | ~25% | Excellent |
| O-1 (1 day before) | ~30% | Best day! |
| O (Ovulation day) | ~25% | Excellent |
| O+1 (day after) | ~0% | Egg likely degraded |
Why Before Is Better Than On
You might expect ovulation day to have the highest success rate, but the day before ovulation (O-1) is actually slightly better. Here's why:
- Sperm need time to travel through the reproductive tract
- Sperm need to "capacitate" (a maturation process) before they can fertilize—this takes 6-12 hours
- Having sperm already waiting when the egg arrives increases the chance they'll meet
🎯 Optimal Strategy
Don't try to "save up" sperm for ovulation day. Have sex every 1-2 days during your fertile window. Aim for at least O-2, O-1, and O for best results. Fresh sperm is better than old sperm.
How to Know When You're Ovulating
Since the fertile window requires prediction (not just confirmation), here are the best methods:
Ovulation Predictor Kits (OPKs)
OPKs detect your LH surge, which occurs 24-48 hours before ovulation. A positive OPK means: have sex today and tomorrow!
Cervical Mucus
Egg white cervical mucus (EWCM) typically appears 2-3 days before ovulation. When you see it, your fertile window is open.
BBT Charting
Basal body temperature rises after ovulation, so it confirms rather than predicts. Useful for learning your pattern over multiple cycles.
Fertility Monitors
Advanced monitors like Mira and Clearblue Fertility Monitor track multiple hormones, giving you more advance notice of ovulation.
Clearblue Advanced Digital OPK
Detects your estrogen rise (before LH surge), giving you 4 fertile days of notice instead of just 2. Clear smiley face results—no line interpretation.
Easy@Home OPK Strips
Affordable strips that detect your LH surge 24-48 hours before ovulation. Use with the free Premom app for tracking.
The Bottom Line
Ovulation itself is a brief moment, and the egg only survives 12-24 hours. But thanks to sperm's ability to survive up to 5 days, your fertile window spans about 6 days.
The key to conception is having sex before ovulation so sperm is waiting when the egg arrives. Focus on O-2, O-1, and O for best results—and use tracking methods to predict when that window opens. 💚