The most common question people ask when they first start thinking seriously about money is not 'how do I invest?' or 'how do I pay off debt?' It is: how much of each paycheck should actually stay in my account?
It sounds like a simple question. It is not. The right answer depends on where you live, what stage of life you are in, whether your income is regular, and what you are trying to accomplish. But there is a simple framework that gives most people a working starting point.
The 50/30/20 rule — and why it needs adjusting
The framework you will hear most often is 50/30/20. Half of your take-home income goes to needs — rent, food, utilities, transport, health. Thirty percent goes to flexible spending — eating out, entertainment, clothes, subscriptions. Twenty percent goes to saving or paying down debt.
This is a useful calibration tool, not a rule. Someone renting in Zurich, Tokyo, or London might spend 70% on needs before they can breathe. Someone who has recently finished paying off student loans might be able to save 35%. The percentages are a starting reference, not a target to hit or feel guilty about missing.
The goal is not to match a percentage. It is to know your percentages — so you can make deliberate choices about which ones to change and which to accept.
The four buckets
A more practical way to think about this is to split your monthly income into four buckets, in this order.
Bucket one: Non-negotiables
These are the costs that exist regardless of what you choose to do this month. Rent or mortgage. Utilities. Health insurance or coverage. Loan repayments. Basic groceries. Transport to work. These costs come first, before anything else.
Add them up. If they exceed 60% of your take-home income, you have a structural problem — one that requires either increasing income or reducing fixed costs. No budgeting technique can solve a structural gap.
Bucket two: A small safety buffer
Before deciding how much to save or spend flexibly, put a small amount — 5 to 10% of take-home, or a fixed number like €100 or CHF 150 — into a buffer you do not plan to spend this month. This is not long-term savings. It is the amount that absorbs the small unpredictable costs that appear every month without being emergencies: a prescription, a transport card top-up, a birthday you forgot about.
People who skip this buffer end up reaching into their savings for things that are not real emergencies, which erodes both the fund and the habit.
Bucket three: Actual savings
What remains after non-negotiables and the buffer gets split between saving and living. The minimum savings amount to aim for is 10% of your take-home income. Not because it is a magic number, but because it is the amount that moves the needle over a year without requiring dramatic lifestyle changes for most people.
Saving 10% consistently for one year produces a meaningful change. Saving 30% for two months and then stopping produces nothing.
If 10% is genuinely not possible right now, start with whatever is. Two percent still teaches the habit. The habit matters more than the amount in the early months.
Bucket four: Everything else
What remains after the first three buckets is what you can spend without restriction. Not guilt. Not negotiation. Just spend it.
This is the psychological release valve that makes the rest of the system sustainable. If every discretionary purchase feels like a moral failing, the system collapses. Knowing that some of your money is pre-authorised for anything you want makes the whole structure easier to maintain.
What to do when the numbers do not work
Sometimes you run the numbers and there is nothing left after non-negotiables. This is real for many people, and no framework makes it disappear. What it tells you is that the budget problem is actually an income problem, a cost structure problem, or both — and the solution is structural, not behavioral.
Do not try to fix a structural problem with willpower. Fix the structure.
The number that matters most
Of all the percentages and buckets, the one that matters most is this: at the end of the month, is there anything left? If there is, even a small amount, you have something to build on. If there is nothing — or if the balance is lower than when the month started — that is the number that needs to change first, before anything else.