1
Set your foundation
Enter your income and fixed bills once. Katana subtracts them up front, so you always see what's truly available to spend.
The art of Kakeibo · 家計簿
Save with
intention.
Know what comes in, cut what doesn't count, keep the rest. Katana turns the century-old Japanese savings method into a calm, deliberate daily habit.
Download on theApp Store
Coming soon toGoogle Play
Now on the App Store — Android coming soon. Free to start; your ledger stays yours forever.
Scan to download
Point your phone's camera here — it opens the right store for your device.
Your month, at a glance
01
Needs
Survival — rent, food, the essentials.
02
Wants
Optional — the nice-to-haves you choose.
03
Culture
Enrichment — books, learning, experiences.
04
Unexpected
The surprises — so they never derail you.
How Katana works
Three steps. One calmer month.
2
Log with intention
Record each expense against a Kakeibo pillar. A single tap keeps you honest about where the money actually goes.
3
Watch it grow
A live savings ring shows what you're on track to keep this month — responsive to every expense, and always ahead of your goal or gently nudging you back.
Everything, nothing more
Built to be used every day.
The savings ring
Your projected savings at a glance — one number that moves the moment you spend.
A real budget engine
Income, fixed, available, committed, spent — the five quantities that tell you the truth, computed for you.
Goals that fund themselves
Set what you want to keep. Katana cascades your savings into each goal, by priority, every month.
Share one book
Partner, family or flatmates on a single household — one goal, one payment, not per person.
Month-over-month trends
A six-month savings curve and category drift, so you can see where the money really moved.
Yours, privately
Your entries and full history are yours forever — export everything, any time, and delete it whenever you like.
“Kakeibo asks four simple questions. How much do you have? How much would you like to save? How much are you spending? How can you improve?”
— the method Katana is built on
Good to know
Questions, answered.
What is Kakeibo?
Kakeibo (家計簿) is a Japanese method of mindful money management from 1904. Instead of automating everything, it asks you to record spending by hand and reflect — which is exactly what builds the habit of saving.
Is Katana free?
Yes. The ledger, your full history, the savings ring, and your first goal are free forever. Premium unlocks shared books, multiple goals, cross-month trends and one-tap reports.
Can my partner and I share a budget?
Yes — Premium puts up to five people on one household book. One goal, one subscription, everyone in sync.
Do you sell my data?
No. Your entries are yours. You can export everything at any time and delete your account whenever you like — we remove it from our servers within 30 days.
Which devices are supported?
Katana is a native iPhone app, available now on the App Store; an Android version is coming soon. Sign in with email, Apple, or Google and your book follows you across devices.
Start keeping what matters.
Download Katana and make this the month your savings finally add up.
Download on theApp Store
Coming soon toGoogle Play