KATSU: Habit Tracker & Routine
Reminders in your own words
Only for iPhone
Free · In‑App Purchases
iPhone
Habits take time. In one study, the median was 66 days. KATSU carries you through them with words you wrote yourself, lets you rest, then tells you to leave.
KATSU is a habit app built to make itself unnecessary.
(Not the cutlet. This one has no recipes in it.)
Set the routines you want to keep. When the time comes and you have not done
one, your phone tells you so — using words you wrote yourself, on the day you
decided to change. Not a template. Not encouragement written by a stranger.
Your own sentence, handed back to you at the moment you are ignoring it.
WHY IT ENDS
Most habit apps need you to keep needing them. Streaks you are afraid to
break, notifications that pull you back, a small guilt when you leave. Their
success and yours point in opposite directions.
This one is built the other way. Do everything on your list on 66 days and
you graduate: KATSU tells you so, hands you a certificate to keep, and shows
you where the cancel button is. Leaving is the point.
Why 66? In one study where people repeated a daily action, the median time
to reach peak automaticity was 66 days — with individuals ranging from 18 to
254 (Lally et al., 2010). The same study found that missing a day now and
then did not set people back much. So KATSU lets you rest: up to two days in
any seven, without losing your place. Rest days do not count toward the 66,
and a third rest day in a week starts the count over.
HOW IT WORKS
• Add a few daily routines — a time and a thing to do. A few times a week?
Make it daily: gym becomes "move for 10 minutes"
• Write what you would say to yourself for skipping one
• Miss one, and that is what arrives
• Check it off any time that day. There is no late
WHAT IT WILL NOT DO
• No scores, no charts, no badges. One number: how far you are toward 66
• Nothing is ever called a failure. A day you miss is just a rest day
• No account, no sign-up, no cloud
WHAT YOU WRITE STAYS ON YOUR PHONE
Your words are never uploaded, never analysed, never logged. There is no
server to send them to. If you delete the app, they are gone — which is the
honest trade for never handing them over.
FREE AND PAID
Everything in the core loop is free: routines, checking off, notifications,
graduation. The paid plan adds more than one set of words, and different
words for different routines.
You choose the price. The plans are identical — the question is what this is
worth to you. Cancel any time from Settings, and if you graduate, you should.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
• Rest days: graduation now means doing everything on your list on 66 days, with up to two rest days in any seven. Resting doesn't send you back to day 1.
• See how far you are: Day 23 / 66 on Today, with your rest days for the week.
• A quiet mark at 7, 33 and 50 days.
• If what you write attacks you rather than what you skipped, KATSU suggests aiming it at today instead. It never stops you saving, and the check runs on your iPhone (Apple Intelligence required).
• Adding, removing or renaming a routine starts the count over. KATSU tells you before it does.
The developer, masahiro obana, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- masahiro obana
- Size
- 55.4 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- All in $19.99
- A first step $4.99
- I mean it $9.99
- Copyright
- © 2026 Masahiro Obana