A private, gentle way to understand your cycle

Honest predictions, shown as ranges

Your body isn't a calendar, so Flow never pretends it is. Future periods and fertile timing appear as a confidence range or gradient band — never a single, falsely certain day.

• Every prediction is a date plus a range, with the peak day clearly labelled
• Uncertainty widens automatically when your history is limited or cycles are changing
• Ovulation is labelled an estimate; a temperature shift can only confirm it retrospectively
• A deterministic engine does the math — so the numbers are consistent and explainable

Your whole cycle, at a glance

A single tulip — the Bloom — greets you each day and reflects where you are in your cycle, from resting bud to full bloom. The Cycle Ring lays out your month with prediction bands you can actually read.

• The Bloom maps your phase to a gentle tulip — never a scary red warning
• The Cycle Ring calendar shows your period and a fertile-window gradient with visible uncertainty
• Exact dates and counts in clean, tabular figures whenever you want the detail

Gentle intelligence, guarded by design

On eligible devices, Petal can phrase what your cycle data already shows — in plain, kind words. It runs on your device, makes zero network calls, and never diagnoses or does the math itself.

• Petal Intelligence phrases facts from Flow's engine — it never calculates a prediction or diagnoses a condition
• Clear templates step in when AI is off or unavailable — nothing ever breaks
• App Lock (Face ID / passcode) and privacy blur in the app switcher keep prying eyes out

Roomy on iPad, glanceable on Watch

On iPad, your Cycle Ring and insights spread out with room to breathe. On Apple Watch, the essentials are a wrist-flick away. It's one app, one purchase, one private record across all your Apple devices.

• Everything is on-device, stored in a protected local database with full-strength file protection
• No iCloud at all — your cycle records are never stored in iCloud, not even your own private one
• No accounts, no servers, no analytics, no ad networks, no third-party trackers — none
• Apple Health is optional and split into three independent choices, all off by default — Flow works fully with every one declined
• Password-protected export and permanent local delete are built in — and never paywalled

We target Apple's “Data Not Collected” privacy label. Put simply: there is no account to breach and no server to raid, because we don't have one. Read the full privacy policy →