Most people do not have a money problem, they have a visibility problem. Here is the simplest budget that works, in one file on your own computer, with nothing connected to your bank.
Four numbers, one month at a time: what comes in, what goes out on things you cannot change, what goes out on things you can, and what you intend to keep.
Everything in there is one of those four. The whole point of the exercise is to see them side by side, because almost nobody ever has.
You do not need an app, a subscription, or a service connected to your bank account. You need one sheet and twenty minutes.
Almost every budgeting product sold is built on the assumption that you are overspending because you lack willpower, and that being nagged about a coffee will fix it.
That is usually the wrong diagnosis.
What most people actually have is no clear picture. Money arrives, several things leave automatically, more leaves in dozens of small pieces, and the balance at the end of the month is a surprise — sometimes a pleasant one. You are not failing to control the situation. You cannot see it.
Which is why the first month of writing it down changes behaviour on its own, before you decide anything. Seeing that six subscriptions add up to a meaningful amount, or that the small daily thing is the size of a utility bill, does more than any amount of resolve. Not because either is wrong to spend money on — but because a choice you can see is a choice, and one you cannot see is just something that happens to you.
Income. Everything that actually arrives, after tax, in a normal month. If it varies, use the lowest of the last three months rather than the average — a budget built on your best month fails in every other one.
Fixed costs. Rent or mortgage, utilities, insurance, loan payments, transport passes, subscriptions. These are the ones that leave whether or not you think about them, which is precisely why they need listing: the total is nearly always higher than people guess, and subscriptions are where it hides.
Variable spending. Food, fuel, going out, clothes, everything else. Do not itemise this to death. One figure per category is enough — seven categories is a budget, forty is a hobby you will abandon in three weeks.
What you keep. This is the line most people compute last, from whatever survived. Put it third instead: decide the amount, take it out at the start of the month, and let variable spending live on what remains. Same arithmetic, completely different outcome, for reasons that are entirely psychological and entirely reliable.
Most budgets are abandoned within two months, and always for the same reasons.
Too much detail. If maintaining it takes more than a few minutes a week, it will not be maintained. Round numbers are fine. Nobody is auditing you.
No allowance for the irregular. Car repairs, dentist, birthdays, insurance renewals — none of these happen monthly and all of them happen. Set aside a monthly amount for them or every third month looks like a failure and eventually you stop looking.
Treating a bad month as a verdict. Some months go wrong. The value is in the running picture over six months, not in any single one.
And building it on your best month rather than your worst. This is the most common structural mistake and the reason a budget that looked comfortable in November collapses in January.
Someone certain they are careful with money, writing it down for the first time.
Income: known. Fixed costs: about a fifth higher than they expected, because four subscriptions had never been counted together and one was for something last used two years ago.
Variable spending: roughly what they thought in total, but distributed differently — considerably more on food bought while out, considerably less on the category they felt guilty about.
Nothing here required willpower. Two of the subscriptions were cancelled in four minutes, the food pattern was a habit rather than a preference, and the amount kept each month went from whatever survived to a figure decided in advance.
Should I connect it to my bank?
Only if you want to. Automatic import saves typing and means handing account access to a third party. A sheet you fill in yourself has no such trade-off, and typing the numbers is part of what makes you notice them.
How detailed should the categories be?
Five to eight. Enough to see where money goes, few enough that categorising takes seconds.
What if my income is irregular?
Budget on your lowest recent month and treat anything above it as extra to be assigned deliberately. This is more work than a salary and the only approach that survives a quiet quarter.
Where should the file live?
On your own computer, backed up where you choose. Your household finances are nobody's business but yours, and there is no reason for them to sit in somebody else's service.
How long before it is useful?
One month to see the picture. Three before the pattern is real. Six before it is genuinely predictive.
The KISS Personal Budget is a single spreadsheet: income, fixed costs, variable spending, savings target, one month at a glance. No bank connection, no subscription, no app deciding what you should have done differently. Three euro, one file.
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