Luteum

Luteum is a period tracker that keeps your cycle to itself. Everything you log stays on your phone. There's no account, no server, and nothing to sign up for — because Luteum never receives your data in the first place. No analytics, no advertising, no third-party trackers. HONEST PREDICTIONS Most trackers print one confident date. Luteum tells you how sure it is. On your first cycle it says "likely 12–22 Oct" and means it. After a few cycles the range narrows to your own pattern. If your cycles are irregular, it says so instead of inventing a number. And if you haven't logged in a long while, it pauses predictions rather than announcing you're 183 days late. There's no "set your cycle length" box, either. Your cycle length isn't a setting — it's the average of your own recent cycles, recalculated every time you log. YOUR OWN PATTERNS • Cycle length over time, with the range you…