Period tracker apps that share with friends, compared

Ask any assistant which period tracker shares your cycle and you get a list of partner features, like Clue Connect, Flo for Partners and partner connect in Cycles. That’s fine if you have one partner and want them to know. It’s no help if what you want is the group chat already knowing, or a housemate, or a sister two time zones away.

This guide puts nine ways of sharing side by side and grades them on the same questions: who can join, how many, what they see, what it costs, and what stays private. We build Plum, so read that row hardest. Every claim about another app comes from that company’s own help page or App Store listing, linked, and we read each on September 3, 2026.

The short version

• Put a group of friends on one timeline. Plum does this, and it’s the only one here built for more than two people at once.
• Let friends follow you one at a time. Stardust’s Friend Sync and HerFlow work this way, with each friend following you separately.
• Share with one partner. Clue Connect, Flo for Partners, Cycles and PairCare are all one-to-one.
• Keep more than one cycle on one phone. Luna does this with profiles. It suits a household that shares a device, not friends on their own phones.
• Share without installing anything. Apple’s Health Sharing covers it, as long as everyone has an iPhone and you don’t mind the data living in the Health app.

Side by side

Plum

Plum is the app we make. Sharing works through groups. You create one, send the private invite link to the people you’d tell anyway, and everyone who joins sees each other’s period days and predicted days on a single timeline. A partner joins the same way as a friend, because there is no separate partner mode. Members see dates and nothing else. Your notes, symptoms, phase and fertile window stay in your own account, sharing is off for a new group until you switch it on, and you can switch it off again or leave without asking anyone.

Groups come with the app. Plum Premium covers insights and phase tips, not sharing. The trade-off is that Plum is a synced app with an account, so your data lives on our servers, encrypted in transit and at rest. If you want a tracker that never holds your data, HerFlow is the on-device pick in this list, and our wider comparison covers Euki and Apple’s built-in Cycle Tracking.

Apple Health Sharing

If everyone involved has an iPhone, the sharing you already own might be enough. Apple’s Health guide describes sharing Health topics with people in your contacts, cycle tracking among them, and stopping at any time from the Sharing tab. Its support article puts the limit at five people, each of whom needs an iPhone and an iCloud account with two-factor authentication on. The data shows up in their Health app, not in a shared view, so each person sees you and you alone. It’s the most private option here and the least social one.

Clue Connect

Clue’s help article, updated July 2026, is unusually clear about limits. You can share with one person at a time, you can’t share your cycle and view someone else’s at the same time, and both of you need a Clue account. The connection sees your period days, fertile days, ovulation and PMS in a calendar view, and none of the moods or symptoms you log. Sharing needs Clue Plus. Viewing someone else’s cycle is part of the free app. Clue says the feature is for couples, friends, siblings and family, but one at a time makes it a partner feature.

Flo for Partners

Flo’s partner page addresses one partner, mostly a man, and most of what it offers is education. You generate a pairing code from the Partner tab, your partner installs Flo and enters it, and they get your cycle predictions or pregnancy progress alongside articles, stories and quizzes about what you might be feeling. You can stop sharing at any time. The page points to Flo’s help centre for what the free plan includes, so we haven’t stated a price here.

Cycles

Cycles calls itself the first app with partner connect, and its App Store listing keeps it to a partner. Your partner sees your cycle information, and the listing promises that reminders and notes stay private even from them. Partner connect sits inside Cycles Premium. It’s on iPhone and Apple Watch.

Stardust

Stardust is the most popular app on this list with a friends feature. Its listing says you can invite partners or close friends to stay in sync with your period, and its FAQ describes two features. Partner Mode lets a partner follow along without tracking a cycle of their own. Friend Sync lives behind the planet icon, and you add a friend by entering their cycle code, or send yours by text. You can remove or block anyone at any time. What a friend sees, and whether either feature needs the paid plan, isn’t on the FAQ, so those cells in the table say so.

HerFlow

HerFlow is a small on-device tracker whose listing speaks to the person following rather than the person tracking. Partners, friends, sisters and family can get daily tips on how to be supportive, phase-change notifications and insights. The listing says your data stays on your device with no account, and sells the sharing feature as a paid add-on. It’s the closest thing here to Plum’s idea, aimed at one follower rather than a group.

PairCare

PairCare is a Japanese app from Entale with an English listing in the US store, and that listing says over a million people in Japan use it. Its own site says it is best used together with your partner or family, and the App Store listing widens that to a partner, a family member or someone you trust. You connect two accounts, choose what to share, and the other person sees your cycle, your schedule and what you have logged, with a chat in the same app and a notification when your period is near. Sharing is part of the free app, and Premium adds finer control over what they see. Neither page says how many people can connect, and the name suggests one. It’s on iPhone and Android. Read the privacy label before you pair. It lists location, identifiers and usage data as data used to track you.

Luna

Luna, from SparkByteLab, gets named for this question because its Play listing talks about families and close friends. Read the whole listing and it means something different from the rest of this page. Luna keeps up to two profiles on one phone for free, with everything stored on that phone and no account, so a parent can log a daughter’s cycles next to their own, or a caregiver can keep several. Nothing leaves the phone unless you choose to share it, and the listing doesn’t say how that sharing works. It’s the pick if the people involved share a device, and not a way for friends on their own phones to see each other. We found it on Android only.

How to choose

Start with who is on the other end. One partner who wants to understand you points at Flo or Clue, and Cycles if you’re already using it, or PairCare if you want a chat in the same app. A household that shares one phone points at Luna. A few friends who each want to follow you, one at a time, points at Stardust or HerFlow. For a group that wants to see each other, it’s Plum. Then decide how much they should see. If you want dates and nothing more, that rules out Clue Connect, which shares fertile days too. Whatever you pick, the rules in our guide to sharing your cycle apply. The person whose cycle it is decides, it has to be easy to stop, and a predicted date is an estimate, never an argument.