Budget book

In short: A budget book records income and expenses so you can see where the money goes and what is left at month end.

In more detail: You record transactions, assign them to categories (rent, groceries, subscriptions, leisure) and compare months. Importing bank statements as CSV saves typing. Fixed costs, variable costs and the savings rate are what matter.

Our context: The budget book tool reads CSV statements directly in your browser, detects recurring payments and outliers, shows the 50/30/20 rule, forecasts the balance and stores nothing on a server.

In Depth

The simple routine

1. Export the bank statement (CSV) and import it.
2. Check categories and correct wrong assignments.
3. Add up fixed costs (rent, electricity, insurance, subscriptions).
4. Look at the difference to your income: that is your room to manoeuvre.
5. Set a monthly limit per category if a spending item stands out.

Key figures

• Savings rate: (income − expenses) / income.
• Fixed cost ratio: fixed costs / income.
• Runway: how many months your balance lasts at current spending.

Privacy

Bank CSVs contain very personal data. That is why it makes sense to use a tool that calculates locally in the browser.

See also: 50/30/20 rule, Emergency fund, Recognising subscription traps