Know your cycle, privately.
Support the people you love.

HerFlow is a private period and menstrual cycle tracking app for iPhone and iPad, made by independent developer Stefan Dasic. It logs periods, flow, moods, symptoms, and notes, shows your cycle phase and estimated next period, and can optionally share your cycle day and phase with a partner or loved one. It is listed on the App Store as HerFlow – Period Tracker and is not related to other products that use the HerFlow name.

Tracking your own cycle is free with no time limit and no ads. The optional People subscription is for the person following someone else's cycle. It starts with a free 7-day trial that needs no payment. After that, you subscribe monthly or yearly at the price shown in the App Store to keep following.

No. There is no sign-up, login, or password. HerFlow never needs your email, phone number, or Apple ID, and the optional name it greets you with stays on your phone. For sharing, the app creates an anonymous credential for your installation behind the scenes; it contains no personal details.

HerFlow has no analytics and no advertising SDKs, and it never sells or shares data for marketing. Flow intensity and contraception details stay on your device, and so do your moods and notes unless you turn on Share this day for a specific day. If you turn on Save to Apple Health, HerFlow also saves your period days, flow intensity, some symptoms and your mood (iOS 18 and later) to the Health app on your device; it never asks to read your Health data. Apple may sync Health data through iCloud, depending on your settings. So that your sharing code works the moment you hand it over, a small cycle summary (recent period days, cycle and period length, current cycle day and phase, and today's symptom tags) is stored on HerFlow's sharing server under your random code, without your name. Sharing is yours to control: switch off Share my cycle on the People tab at any time to delete the summary and stop all uploads. The privacy policy describes this in full.

Yes, and only if you want to. Every HerFlow profile has a random code such as HF7FQ9D3. Give it to your partner, and once they enter it in their copy of HerFlow they see your cycle day and current phase, get notifications when your period is due or a phase changes, and receive daily tips on how to support you. They do not need a login from you, because there is none, and HerFlow never shows them your name. It works the same for a boyfriend, husband, girlfriend, friend, or family member.

No. HerFlow is not a medical device and not a contraceptive. Its fertile window and ovulation estimates are for understanding your cycle, not for preventing or planning a pregnancy. Talk to a healthcare professional about contraception or conception.