How this actually works
Most cycles follow a predictable pattern: ovulation tends to happen about 14 days before your next period starts, not 14 days after the last one — which is why cycle length matters more than most calculators let on. Once we know your ovulation day, your fertile window is the five days before it plus the day itself, since sperm can survive a few days waiting around while the egg is the one on a strict schedule.
This tool gives you an estimate based on average cycle patterns. Real cycles vary — stress, travel, illness, and plain bad luck all nudge things around. Tracking a few cycles in a row (or checking ovulation predictor kits or basal body temperature) will always beat a calculator alone.
Frequently asked
Do I need to make an account?
No. Nothing here is saved, stored, or sent anywhere. Close the tab and it's gone — refresh and you start fresh.
How accurate is this?
It's an estimate based on average cycle math, not a diagnosis or a guarantee. If your cycles are irregular, or you're tracking for a specific medical reason, pair this with a doctor's guidance or a more precise method like ovulation strips.
Can I use this to avoid pregnancy instead?
This tool is built to estimate your most fertile days, not as a form of contraception. Cycle-based methods for preventing pregnancy require much stricter tracking and should be learned from a healthcare provider.
Why does the egg look like that?
Honestly, we just liked the idea of a little egg having feelings about your cycle. No deeper meaning. It seemed friendlier than a calendar icon.