Plum

A period tracker for you and your friends.

Log a period in two taps on your iPhone and see when the next one is due. Then create a group with your friends.

Free to downloadNo adsWe never sell your data
A Plum group called Inner circle: four friends' period days and predicted days side by side on a shared timeline, with an Invite friends button.
Plum's home screen: a cycle ring on day 20 in the luteal phase, 7 days until the next period, and quick chips for feelings, energy and sleep.
Plum's calendar for August and September 2026 marking logged period days, predicted period days, the fertile window and ovulation.
Groups

See where your friends are in their month.

Send a private link to the people you’d tell anyway. Everyone in the group sees each other’s period days and predicted days on one timeline, so nobody has to ask.

Members see your period dates. Your symptoms and moods stay private.
Sharing is on from the moment you join, and every group has its own switch you can turn off whenever you like.
Start a groupHow sharing with friends works
A Plum group called Inner circle: four friends' period days and predicted days side by side on a shared timeline, with an Invite friends button.
Features

How Plum works

Plum's log sheet for August 21 with period flow set to medium, plus cravings, energy, feelings and mind chips.
1

Log in two taps

Tap yes and pick a flow. Plum fills in the rest of the period for you.

Plum's calendar for August and September 2026 marking logged period days, predicted period days, the fertile window and ovulation.
2

Predictions that learn

Plum predicts your period, fertile window and ovulation from your own cycles, and gets sharper with each one you log.

Plum's home screen with a cycle summary card and four tips for today: Reduce Volume, Warming Teas, Less Caffeine and Warm Meals.
3

Tips for the phase you're in

Each tip says what to eat, drink and ease off on this week, and why.

Plum at a glance

What it is
A period tracker for iPhone. It predicts your period, fertile window and ovulation from what you log, and it can remind you to take your birth control.
What's included
Logging, predictions, reminders, groups and the cycle phase you're in all come with the app. Plum Premium adds insights and phase tips as a subscription, and the App Store shows the price for your country.
Platforms
Plum is an iPhone app. There isn't an Android version yet.
Sharing
You share through groups that friends join by private link. They see your last period, your next expected one, and whether you're on your period today. If you track exercise, they also see which days you worked out, never what you did.
Your data
It's encrypted on Plum's servers and is never sold or used for ads. You can delete your account and everything in it from inside the app.
What it isn't
Plum isn't a medical device, and its predictions aren't a form of contraception.

What happens to your data

EncryptedPlum encrypts your data in transit and at rest.
Never soldPlum never sells your data or uses it for advertising.
Yours to deleteRemove your account and its data from inside the app.
How Plum handles your dataPrivacy policy
Plans

What's free and what Premium adds

IncludedEverything you need to track
Period and cycle logging
Calendar with predictions
The cycle phase you’re in, on the home screen
Period, ovulation and birth control reminders
Groups with friends
Plum PremiumUnderstand your patterns
Insights that connect your symptoms to your cycle
Tips for every phase, with the reason behind each one
A notification when new insights are ready or a new phase starts
Start the free trialPay yearly or monthly. The yearly plan starts with a free trial. The App Store shows your price, and the subscription renews until you cancel it there.
Free calculators

Work out your next period right here

You don’t need the app or an account. Type in a couple of dates. Each calculator runs in your browser and uses the same math as the app.

Period calculatorWork out your next six periods, fertile windows and ovulation dates from one date.Open the calculatorPeriod calculator for irregular periodsMeasure the real gaps between your periods. See the range your next one is likely to fall in.Open the calculatorLate period calculatorCheck whether your period is late, by how many days, and when a pregnancy test will work.Open the calculatorCycle length calculatorCount the days between your periods. See your average cycle length and how it compares with the normal range.Open the calculatorCycle phase calculatorSee which phase of your cycle you’re in on any day, and when each phase starts and ends.Open the calculatorPMS calculatorSee when PMS can start before each of your next three periods, and when it usually eases.Open the calculator
Guides

Read up on your cycle

We write longer guides on cycle length, the fertile window, irregular periods and how to pick a tracker. Every guide links its sources.

All 21 guides
How long is a normal menstrual cycle?This guide explains what cycle length means, whether 28 or 35 days is normal, how many periods a year to expect, and what to get checked.Read the guideHow late can a period be?Being a week late once in a while is ordinary. See what counts as late day by day, when a pregnancy test becomes reliable, and when to call a doctor.Read the guideWhat is the fertile window and how is it calculated?The fertile window is the few days each cycle when pregnancy is possible. Here's how apps and clinicians estimate it, and where the estimates fall short.Read the guideDo periods sync with friends?Periods feel like they sync with friends and roommates, but the studies say no. Find out why the overlap happens and how to share dates instead.Read the guideIrregular periods: common causes and when to see a doctorStress, travel, PCOS and thyroid problems are common reasons periods go irregular. Find out which signs need a doctor and how to track them.Read the guideHow to choose a period tracker that respects your privacyPeriod apps hold your most sensitive data. This guide shows how to tell which trackers sell or share it, with a checklist for reading a privacy policy.Read the guide
Questions

Before you download

Can my friends and I all see each other's periods in Plum?

Yes. That's what groups are for. One of you creates a group and sends the private invite link, and everyone who joins sees each other's period days and predicted days on one shared timeline. A group holds up to 100 people, each on their own iPhone with their own Plum account, and groups come with the free app.

What does Plum cost?

Plum is free to download. Logging, the calendar, predictions, reminders and groups come with the app. Plum Premium adds insights and phase tips as a yearly or monthly subscription. The yearly plan starts with a free trial. The App Store shows the price for your country before you buy.

Is Plum on Android?

Not yet. Plum is an iPhone app.

Is this the same app as Plum: Period & Cycle Tracker?

No. That's a different app from a different developer. This Plum is Plum Period Tracker & Diary by Sticky Rice Labs, the one this site describes. Check the developer name under the title on the App Store so you get the one you meant.

Who can see what I log?

Only you, unless you're in a group. Each group has a sharing switch that starts on when you join. Members see your last period, your next expected one, and whether you're on your period today. If you track exercise, they also see which days you worked out, never what you did. Your symptoms, moods and fertile window stay private. A partner joins a group like anyone else, because Plum has no one-to-one mode.

Is my data on my phone or on a server?

It's on Plum's servers, encrypted in transit and at rest. That's what lets your history survive a new phone and lets groups work. You can delete your account and everything in it from inside the app whenever you like.

Does Plum show which phase of your cycle you're in?

Yes, on the home screen, and it's free. Plum shows your cycle day and the phase you're in now, which is your menstrual phase, your follicular phase, ovulation or your luteal phase. Tap it to read what that phase is, what you may notice in your body and your mood, and which hormones are behind it. Plum Premium adds a daily tip for the phase you're in and a notification when a new phase starts.

How accurate are the predictions?

They start from a typical cycle and adapt to yours with each period you log. Plum tells you when it's still learning instead of pretending to be sure.

Does Plum track birth control?

Yes. You can log the method you use and set a reminder for it. If you change time zone, Plum offers to move the reminder so it stays on your original schedule. Plum's cycle predictions aren't contraception, so don't rely on them to prevent pregnancy.

How do I cancel Premium?

Open iPhone Settings, tap your name, then Subscriptions. You keep Premium until the paid period ends. Deleting the app doesn't cancel it.

Something else? We answer every email.
Plum

Start with your next period.

Plum is free to download and takes a minute to set up. Log your first period and it starts learning your cycle from there.

Download Plum on the App StoreiPhone only for now.
PlumFree on the App Store
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