Four Phases

Four Phases is a cycle tracker built for men. Track her four phases. Get AI coaching on food, conversation, and what to plan, so you show up when it matters.

Four Phases is the cycle tracker built for the other half of the relationship.

Every month, her body cycles through four distinct phases, menstrual, follicular, ovulation, and luteal. Each one feels different. Each one needs something different from you. Most guys never learn this. Four Phases changes that.

Set up her cycle once, just her last period and average cycle length. Four Phases predicts the rest. Open the app any day to see exactly where she is, what's probably going on for her, and what you can do today to show up for her.

WHAT YOU GET

• Daily phase view showing exactly where she is today and how far through • Daily Brief from the AI Coach: one concrete move, why it matters, what to say, what to skip, and a food tip, with a message you can copy and send • Coach chat and a toolkit (gift ideas, date plans, grocery runs, what-to-say scripts) for in-the-moment situations • Per-phase guides covering her energy, mood, what she needs, what to avoid, conversation starters, and date ideas • Calendar color-coded by phase, with her most fertile day marked • Reminders before phase transitions ("Luteal starts tomorrow") so you're never caught off guard • Optional Live Sync so her real dates flow to your app automatically • Built dark, designed for guys, no pink, no flowers, no clinical jargon • A free account keeps your setup on every device and links you to her

WHY FOUR PHASES EXISTS

Period-tracking apps were built for the person bleeding. Four Phases is the other half, built for the partner who wants to understand what's going on without making it weird. The information already exists. Most guys just don't have it organized in a way they'll actually use. Four Phases organizes it. The AI Coach turns it into a daily action.

Being a good partner is mostly about showing up at the right time. Four Phases tells you when, and how.

PRIVACY

Four Phases runs on a free account, because the point of it is to link two people: what she logs reaches your app, and what you set up follows you to a new phone. That means your cycle data, logged symptoms, notes and Coach history are stored in your private account, protected by row-level security so only you and the partner you link can ever read them. No ads, no data brokers, no cross-app tracking, no third-party analytics SDK.

Her name is never sent to the AI, the app strips it on your device before any Coach request leaves. Usage analytics are a random install ID and an event name, never cycle data or anything you or Coach wrote.

Delete any of it whenever you like, from inside the app: "Wipe it" clears your data and keeps the account, "Delete my account" erases the account and everything in it from our servers for good.

NOT MEDICAL ADVICE

Four Phases is educational software designed to help partners understand the menstrual cycle. It is not a medical device, not a diagnostic tool, not contraception, not fertility planning. If something seems off about your partner's health, talk to a real clinician.

Four Phases is free. Create an account with any email and you're in.

Built by a small team in Tampa Bay.