The fertile window, explained for men
Nobody taught you this in health class because health class was busy showing you slideshows. Here's the actual mechanism, in plain English, with the numbers.
The three facts that matter
- Ovulation counts backward. The egg releases about 14 days before the next period starts — not 14 days after the last one. Cycle length changes the front half, not the back half. That's why guessing from "day 14" fails on any cycle that isn't exactly 28 days (which is about 87% of them).
- Sperm are patient. Up to 5 days of viability inside the body. The risky window opens days before ovulation, because Tuesday's decisions are still in play on Saturday.
- The egg is not. Roughly 24 hours of viability after release. Once it's gone and the luteal phase settles in, the biology closes for the month.
Put together: about six biologically fertile days per cycle, positioned by a moving ovulation date, wrapped in uncertainty because real cycles vary month to month. RAWDOGGER renders that as a red core with yellow shoulders — the danger week — instead of asking you to do luteal-phase arithmetic in your head.
The numbers, honestly
Calendar-based awareness methods run a typical-use failure rate around 24% per year — better than nothing, much worse than actual contraception. (For contrast, typical-use condoms run ~13%/yr; the only FDA-cleared app for contraception is Natural Cycles, which requires daily body-temperature data — a different product doing a different job.) We publish these numbers because the entire RAWDOGGER brand is honest odds: the app shows you the same math on its legal screen before you ever see a calendar.
What this means in practice
Track, don't guess — a real period date beats a vibe. Treat yellow days as red if the stakes are high. Understand that green is "better odds," never "no odds." And if you cannot afford to be wrong, use actual contraception — this is a cycle awareness tool, not a contraceptive, and none of this is medical advice. For the real medical version, the CDC and ACOG publish fertility-awareness guidance worth ten minutes of your life.
Let the app do the math
Open RAWDOGGER, enter one date, and see the window painted on a calendar — announced, if you upgrade, by a crew with strong opinions about your weekend.