otty Download on the App Store
Never drift apart

The period tracker
that explains your cycle.

See your next period and ovulation day ahead of time, with one tip each day and the reason it works. Use it solo or together. Otty works the same whether the cycle is yours or your partner's.

Download on the App Store

Private by default.

Her phone, 7:00 AM
Storm (Period) Day 1 · Low energy is real
Estrogen and progesterone are at their monthly low right now, and energy usually dips with them. An earlier night tonight is working with your body.
His phone, 7:00 AM
Storm (Period) Day 1 · Why she's tired
Her estrogen and progesterone just hit their monthly low, which shows up as real fatigue. Taking dinner or dishes off her plate tonight lands well.
The Otty Today screen on an iPhone
One month, painted by phase

The calendar you both open

Tap any day to see the phase, what Otty expects, and what has helped before. Both phones show the same month, painted the same way.

Storm (Period)
Chill (Follicular)
Glow (Ovulation)
Zen (Luteal)
Pre-Storm (PMS)
Ovulation
Period Starts
Milestone
Check-in logged
Read the phase guide below
The calendar

What people wrote on the App Store

A
Cycle Owner
App Store review

Actually helpful tips!

"Beyond tracking my period, I love that it gives me practical tips on what to do and what to eat during each phase of my cycle. It feels like so much more than just a period tracker!"

A
Tracks Wife's Cycle
App Store review

Learned a lot!

"I got Otty to understand my wife's cycle and honestly I've learned way more than I thought i would."

T
Tracks Her Cycle Solo
App Store review

Incredibly Helpful

"She's not even on the app, I just track it myself. I know where she's at each week and what that means for her without having to ask."

D
Tracks Girlfriend's Cycle
App Store review

Love this app

"honestly downloaded this just to make my girlfriend happy lol but now i actually check it every morning. knowing what phase she's in changes everything."

O
Paired With Husband
App Store review

Best app

"The fact that this is built for both people and not just the girl is everything. My partner checks it on his own now."

J
Paired With Girlfriend
App Store review

Love the love notes

"She gets so much more excited about a love note from the app than a regular text. Started doing it and now it's just our thing."

S
Paired With Wife
App Store review

Just makes sense

"We both have it and it just works. I know what she's going through, she doesn't have to explain herself, and we're better for it."

L
Paired With Boyfriend
App Store review

He just knows now

"My boyfriend tracks my cycle with me on here and I feel so much more understood!"

M
Cycle Owner
App Store review

Always know what's coming

"I use Otty to track my cycle and the period predictions are always spot on. I always know when my period is coming and when I'm ovulating."

Every quote above is a real App Store review, word for word.

Download on the App Store

One cycle, two people, the same Tuesday

Everything below happens on day 1, which is Storm (Period). Her phone is on the left, the person helping is on the right, and they do not get the same message.

Lane one
The person whose body runs on the cycle
Lane two
The person who wants to help
7:00 AM · the heads-up
Otty, once a day
A heads-up from your last cycle

Around this day last cycle you logged cramps. Plan tonight a notch softer, just in case.

7:00 AM · the same morning
Otty, once a day
Storm (Period) Day 1 · Cramp science

Her cramps are real uterine muscle contractions, and heat relaxes the muscle. Charging the heating pad or running a warm bath genuinely helps.

Daily log
Daily check-in
How was today?
Otty says

Cramps are your uterine muscle contracting. Heat on your lower belly genuinely relaxes it, and ibuprofen works best taken early.

What to do about it

Today's playbook

Do today
  • Heating pad charged and in reachShe logged cramps
  • Pre-fill water bottle
  • Handle the dishes
Skip today
  • Plans that keep her standingShe logged cramps
  • "Are you okay?" on loop
  • Loud restaurants
The phase guide

Five phases in one cycle, and what each one actually feels like

Every nudge, playbook, and heads-up in Otty starts from this guide, so we have printed it here in full for both of you.

01 · Storm (Period)

StormInner winter

Days 1 to 5. Rest mode. This is the lowest energy of the cycle.

The body is shedding and resetting, so cramps, fatigue, and mood swings are ordinary weather. Comfort is the only objective.

Cramps Fatigue Cravings
MoveKeep it to walks and gentle stretching.
EatLean on iron-rich meals, dark chocolate, and warm food.
LoveTake the errands this week, and have the heating pad warm by day two.
02 · Chill (Follicular)

ChillInner spring

Days 6 to 9. Rising energy. Momentum builds day by day.

Recovery turns into a steady climb. Mood lifts, creativity spikes, and this becomes the fresh-start stretch of the cycle.

Mental clarity Better sleep Creativity
MoveTry a new workout, some cardio, or a dance class.
EatKeep plates light and fresh, with something fermented.
LovePlan a small adventure, and suggest the date yourself.
03 · Glow (Ovulation)

GlowInner summer

Days 10 to 15. Peak energy. This is the fertile window.

Estrogen peaks and testosterone surges, so confidence, social warmth, and communication all land at their best for these six bright days.

Peak confidence Glowing skin High libido
MoveGo hard with intervals, running, or a group class.
EatFavor vegetables, lighter plates, and less of the heavy stuff.
LoveSay the compliment out loud, because it lands best this week.
04 · Zen (Luteal)

ZenInner autumn

Days 16 to 22. Cozy mode. Nesting takes over, steadily.

Progesterone takes the lead, which makes everything calmer, warmer, and more home-shaped. Quality time outperforms big plans every time.

Nesting Calm focus Comfort-seeking
MoveWalk, do Pilates, or lift something light.
EatReach for complex carbs, magnesium, and warm comfort food.
LoveStay in and be present, because that beats a big production.
05 · Pre-Storm (PMS)

Pre-StormLate autumn

Days 23 to 28. Recharging. Sensitivity rises through the week.

Both hormones drop sharply, and that is the real reason behind PMS rather than drama. Patience is the whole game for these six days.

Irritability Bloating Low patience
MoveStick to walks, yoga, and stretching.
EatAdd magnesium, B6, and omega-3s, and ease off the caffeine.
LoveAsk whether she wants space or comfort, then deliver that one.

Day counts assume a 28-day cycle and shift with yours. Otty is a companion, not a clinician, and nothing here is medical advice.

Not tracking

Four ways Otty brings you closer that have nothing to do with logging

Each one is matched to the phase, so Storm nights suggest soup and Glow days suggest a long walk.

Comfort Coupons

Ninety pre-written promises arrive in phase packs, and your partner cashes one in when they need it.

Storm (Period) pack

Heat Valet

Heating pad valet: heat, blanket, drink, and the remote, all set up by me.

Glow (Ovulation) pack

Mystery Date

One surprise mini-date this week. You only get the dress code.

Let's Roll

A gumball machine picks tonight's plan and matches it to the phase.

Tonight's plan

Matched to Pre-Storm (PMS), the phase you are in today.

Tonight: Bath and chocolate

Run a bath, hand over the good chocolate, and let the evening stay small.

Deck Night

Three hundred conversation cards across six decks, played on one phone. Draw a card, read it out loud, both of you answer.

Comfort & Care

What does being taken care of actually look like for you?

Card 3 of 50

Comfort Menu

The person with the cycle writes down once what helps in each phase, so nobody has to guess at 9 PM.

1 Heating pad, warmed and handed over
2 Never ask if it is my period
3 Check on me once, then let me be
1 Plan the adventure while I have juice
2 Say yes to my spontaneous ideas
3 Do not park my good weeks on the couch
1 Specific compliments, not generic ones
2 Romance the buildup, do not skip ahead
3 Do not credit my confidence to hormones
1 Routine over novelty this week
2 No surprise plans or last-minute changes
3 Start stocking snacks, cravings incoming
1 Ask me: listen, space, or solutions?
2 Never ask if I am PMSing
3 Take decisions off my plate

All four come with Otty, and Otty picks the one that fits the day you are on.

Download on the App Store

Questions people ask first

The six answers below are in plain language. Anything else goes to ottyteam@gmail.com and a person reads it.

Who is Otty for, me or my partner?

Whoever wants to. Either of you can install Otty first. Tell Otty when the last period was, and both of you see the same calendar: what’s coming, what’s here, and how to prepare. Otty works on its own too, and the shared parts stay quiet until you pair up.

Is Otty free?

The first seven days are free. After that it is $5.99 a month or $39.99 a year. Cancel in Settings before day seven and you are not charged.

What does my partner actually see?

Only what you turn on, item by item. When check-in sharing is on, your partner sees the mood and symptoms you logged on their own Today screen and calendar, plus a heads-up before days that have been rough before. You can switch any of it off in Settings.

What languages does Otty speak?

English, Spanish, and French, including all 300 conversation cards and all 90 coupons. Otty follows your iPhone language and you can change it in Settings.

My partner has an Android phone. Now what?

Otty is on iPhone only today, and Android is an email list rather than a download. Leave your address in the box further down this page and we will write once, on the day it is ready.

Is any of this medical advice?

No. Otty is a companion, not a clinician, and it will never tell you what is wrong with your body. For medical questions, please talk to a doctor.

Every answer above is easy to check against your own week.

Download on the App Store
or skip the scrolling...

Let Otty tell you what to do, every day.

One app for both of you, with daily nudges, tips written for the phase you are in, and a calendar that knows what is coming.

Download on the App Store
Private by default.
Android is on the way

Sign up to be the first to know.

Otty speaks English, Spanish, and French, and that includes all 300 conversation cards and all 90 coupons.
From the zine

Reading, for the weeks between.

Browse the whole blog →
Free tool Period calculator: predict your next period Enter your last period and cycle length, and get your next three periods and fertile windows. Glow phase Best Period and Ovulation Tracker App: 7 Compared (2026) The best period and ovulation tracker app depends on how it finds ovulation: Natural Cycles works it out… Pre-Storm phase Perimenopause Period Tracker: 6 Apps Compared (2026) A perimenopause period tracker has to do something most apps were never built for: keep an honest record… Pre-Storm phase Best Period Tracker App: 10 Compared by Who They Fit (2026) The best period tracker app depends on the one job you need it to do. If you want… Storm phase Apple Health Period Tracker Review: Accuracy and Limits The Apple Health period tracker, which Apple calls Cycle Tracking, is a free, private and genuinely good period… Zen phase Period Tracker for iPhone Duo: Which Apps Fill the Screen A period tracker for iPhone Duo has to do three things a phone app never did: fill a… Glow phase Best Couples Apps for iPhone Duo: Which Use Both Screens Couples apps for iPhone Duo are a different question from couples apps on a normal phone, because the… Chill phase Best Couples Apps in 2026: 8 Compared by What They Fix The best couples app is the one built for the job you actually have. Some couples need help…