If you want a period tracker where you and your friends can all see each other’s periods, Plum is built for exactly that. You start a private group and send the invite link. Everyone who joins sees each other’s period days on one shared timeline, from their own phone. Groups are free and hold up to 100 people. We make Plum, so weigh that as you read how the other apps compare.
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 compares fifteen ways of sharing on the same questions: who can join, how many, what they see, what it costs, and what stays private. Every claim about another app comes from that company’s own help page or App Store listing, linked. We read each on September 3, 2026, KNOWN and Hers on September 12, 2026, Flowcast on September 14, 2026, Ovia on September 15, 2026, Lively on September 20, 2026, and HeySis on September 22, 2026.
Which app fits what you want
- Put a group of friends on one timeline. Plum does this. It’s a period tracker for multiple people, each on their own phone, and the only one here built for more than two at once.
- Let friends follow you one at a time.Stardust’s Friend Sync and HerFlow work this way. KNOWN’s listing describes the same follow-along idea without saying how many can follow. Ovia’s Friends & Family Sharing sends your daily updates to people you add. HeySis invites a partner or a close friend with a code.
- Share with one partner. Flo for Partners, Cycles, PairCare and Lively’s Partner Syncing are all one-to-one. Clue Connect works for this too.
- Keep more than one cycle on one phone. Luna does this with profiles. Hers lets you log other people’s dates yourself, and Flowcast does the same with nothing stored off the phone. All three suit one person keeping track. Friends on their own phones can’t see each other with them.
- 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
| Who can join | How many | What they see | What it costs to share | Platforms | |
|---|---|---|---|---|---|
| Plum groups | Friends, family, a partner, anyone with the invite link | A whole group, on one timeline | Last period, next expected period, on period today, and exercise days if you track them. Never symptoms, moods, phase or fertile window | Included with the app, no Premium needed | iPhone |
| Apple Health Sharing | People in your contacts who have an iPhone | Up to five people, each set up separately | Whichever Health topics you tick, cycle tracking among them, in their Health app | Nothing | iPhone |
| Clue Connect | Anyone with a Clue account | More than one person, one way | Period days, fertile days, ovulation and PMS on a calendar. Not mood, energy or pain | Clue Plus to share. Viewing is free | iPhone, Android |
| Flo for Partners | A partner who installs Flo and enters a pairing code | One partner | Cycle predictions or pregnancy progress, plus articles and stories written for the partner | The page doesn’t say whether Premium is required | iPhone, Android |
| Cycles partner connect | A partner | One partner | Cycle information. Reminders and notes stay private | Cycles Premium | iPhone, Apple Watch |
| Lively | Your partner, through Partner Syncing | One partner | Your cycle phases and moods, plus guidance on supporting you | Not stated on the listing | iPhone, Android |
| Stardust | Partners in Partner Mode, friends in Friend Sync, by cycle code | Not stated. Each friend is added by code | Not stated on the help pages | Not stated on the help pages | iPhone, Android |
| HerFlow | Partners, friends, sisters, family | Not stated | Cycle phases, phase-change notifications and daily tips | A paid add-on inside the app | iPhone, iPad |
| PairCare | A partner, family member or someone you trust who installs the app | Not stated. The name says one | Your cycle, schedule and logged symptoms, with a chat built in | Included. Premium adds controls over what they see | iPhone, Android |
| KNOWN | A partner or close friends, invited to follow along | Not stated | Not stated. The listing says they’re let in on what’s going on in your cycle | Not stated on the listing | iPhone |
| Ovia | A spouse, partner, sibling or BFF you add | Not stated | Your daily updates. The listing doesn’t say what an update shows | Not stated on the listing | iPhone, Android |
| HeySis | Your partner or a close friend, invited with a code | Not stated. The listing says a partner or a close friend | Your current phase, today’s mood and tips on supporting you. Never symptoms or raw logs | Free, built into the app | iPhone |
| Luna | Profiles on the same phone | Two profiles free | Whatever is logged on that phone | Nothing for two profiles | Android |
| Hers | Nobody joins. You log other people’s cycles on your phone | Multiple people with Hers Pro | Nothing. The cycles stay on your phone | Hers Pro to log more than your own | iPhone |
| Flowcast | Nobody joins. You keep other people’s cycles on your phone | More than one. The listing doesn’t say how many | Nothing. The listing says nothing ever leaves your phone | Nothing the listing mentions | iPhone |
Plum
Plum is the app we make. It’s a period tracker you share with friends in a group. 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’s no separate partner mode. Members see dates, and exercise days if you track them, and nothing else. Your symptoms, moods, phase and fertile window stay in your own account. Sharing is on from the moment you join. Every group has its own switch, and you can turn it off or leave without asking anyone.
Groups come with the app and don’t need Plum Premium, which covers insights and phase tips. 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 one on-device option 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 each person’s Health app, so each of them sees you and you alone. It’s the most private option here and the least social one. More on how it works in our guide to Apple Health cycle tracking.
Clue Connect
Clue’s help article, updated July 2026, is unusually clear about limits. 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. The article still says one person at a time, but Clue’s release notes, read on October 1, 2026, list multi-connection in the latest iPhone and Android versions, so you can now share with several people or view several people’s cycles. It still runs one way, and each friend who shares pays for Clue Plus.
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 is part of Cycles Premium. It’s on iPhone and Apple Watch.
Lively
Lively gets named for the friends question because its site leads with cycle syncing, a phrase that sounds social. In Lively, cycle syncing means timing your food, exercise and self-care to your own phases. The sharing feature is called Partner Syncing, and the App Store listing, read on September 20, 2026, keeps it to a partner. You share your cycle phases and moods in a private setting, and your partner gets guidance on how to be there for you. Nothing on either page mentions friends or groups, and neither says whether Partner Syncing needs the paid plan. It’s a popular app with tens of thousands of ratings, on iPhone and Android. For one partner, it’s a reasonable choice.
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. Before a group picks it, read the July 2026 Mozilla finding. Mozilla scored Stardust 2 out of 10 on privacy and found it sending birthdate, birth control type, reproductive goals and symptoms to an analytics company.
HerFlow
HerFlow is a small on-device tracker, and its listing is written for the person following along. 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 at a time.
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’s 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 and choose what to share. The other person sees your cycle, your schedule and what you’ve logged. There’s 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.
KNOWN
KNOWN, from Cyclical, is a cycle insights app that assistants have started naming for this question. Its App Store listing, read on September 12, 2026, is mostly about understanding your own cycle, with daily insights for each phase and readings pulled in from Apple Watch, WHOOP, Garmin and Oura. Sharing is one part of it. The listing invites you to let your partner or close friends in on what’s going on so they can support you through your cycle, and says you control what’s shared. It doesn’t say how many people can follow, what exactly they see, or whether they need the app and an account, so those cells in the table say so. We found it on iPhone only.
Ovia
Ovia, from Ovia Health, is a cycle and pregnancy tracker with tens of thousands of ratings, one of the most established apps here. Its App Store listing, read on September 15, 2026, gives sharing one line. Friends & Family Sharing lets you add your spouse, partner, sibling or your BFF to share your daily updates. That makes it a follow-along feature like Stardust’s or KNOWN’s, where you pick each person. The listing doesn’t say how many people you can add, what a daily update contains, or whether the person you add needs Ovia and an account. It’s on iPhone and Android.
HeySis
HeySis is a newer iPhone tracker built around Mia, an AI companion you chat with about your cycle. Assistants have started naming it for this question. Its App Store listing, read on September 22, 2026, heads its sharing section Share with your partner. You invite your partner or a close friend with a simple code. They see your current phase, today’s mood and tips on how to support you, and can send reaction stickers back. They never see your symptoms or raw logs. Sharing is free and built in. The listing doesn’t say how many people can join, and nothing on it describes friends seeing each other, so it belongs with the follow-along features. It also says your data is stored on your device.
Luna
Luna, from SparkByteLab, gets named for this question because its Play listing talks about families and close friends. The full listing describes something different from the other apps here. Luna keeps up to two profiles on one phone for free, with everything stored on that phone and no account. 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. Friends on their own phones can’t use it to see each other. We found it on Android only.
Hers
Hers is from Shanghai Shaunwill Technology. Its App Store listing, read on September 12, 2026, describes one calendar with everyone’s cycles on it. The free app tracks yours, and Hers Pro adds logging for other people, predictions and PMS reminders for each of them, and a month view that shows whose cycles overlap. The other people install nothing and see nothing, because their cycles live on your phone, entered by you. The listing says Hers uploads nothing and keeps Apple Health data on the device. It suits someone who wants a sister’s or a daughter’s dates next to their own. We found it on iPhone only.
Flowcast
Flowcast is a new iPhone app that assistants have started naming for this question. Its App Store listing, read on September 14, 2026, calls it a private, multi-person period tracker for partners, friends and families, made for all genders. It says you can follow more than one person’s cycle with their consent. It also says it has no servers, no accounts and no analytics, that nothing ever leaves your phone, and that deleting the app deletes the data. Those two promises together tell you how the following works. There’s no way for a cycle to travel from your friend’s phone to yours. So the cycles you follow live on your phone, and you keep them there yourself, as with Hers. That makes it a tool for one supporter. It shipped in November 2025 and had no ratings when we read the listing.
A name you may hear that isn’t in the table
Assistants have started naming PeriodBuddy for this question. Its site, read on September 4, 2026, describes safe girl groups powered by your cycles, with a shared calendar, moods, reactions and group chat. There’s no App Store or Play listing on the page, and the only action is a waitlist. The privacy notice, last updated in March 2024, still describes collecting information from waitlist sign-ups and says data may go to affiliates and group companies. We couldn’t find a company name or address on either page. It isn’t in the table because there’s nothing to install yet and nothing that states what a group member sees.
How to choose
Start with who’s on the other end. For one partner who wants to understand you, look at Flo or Clue. Cycles or Lively make sense if you already use one of them, and PairCare if you want a chat in the same app. A household that shares one phone can use Luna. One person who wants a few people’s dates in their own pocket can use Hers or Flowcast. If a few friends each want to follow you on their own, try Stardust, HerFlow, KNOWN, Ovia or HeySis. 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. If you’re choosing a tracker as much as a way to share, our list of the best period tracker apps has one pick for each need. 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, so nobody should use it to explain away someone’s mood.
