You now know how much comes in, how much goes out and how each type of expense behaves. It’s time to build the real budget: deciding, in advance, how your money is split. And the key here is that a good budget isn’t a straitjacket that tells you “don’t spend,” but a plan that gives permission: once split, you can spend your leisure share guilt-free, because you know savings and needs are already covered. In this chapter we’ll see three methods for splitting, from simplest to most detailed, so you can choose the one that fits your family.

Why you need a split

Without a split, money is spent on a first-come basis: you pay whatever is due and, at the end of the month, you save what’s left… which is almost never anything. It’s the classic trap, and the reason so many people with decent income can’t manage to save.

A splitting method reverses the logic. Instead of spending first and saving later, you decide in advance what proportion goes to each thing and stick to it. The mental shift is huge: you stop asking “can I afford this?” with every purchase, because you already decided it calmly at the start of the month. The budget thinks for you, and you spend with peace of mind within the limits you set yourself.

There’s no single correct method. The best one is the one you’ll actually use. So it’s worth knowing several and keeping the one that creates the least friction for you.

The 50/30/20 rule

It’s the most popular method for its simplicity, and an excellent starting point. It splits your net income into three blocks:

50% to needs. What you can’t stop paying: housing, utilities, basic food, essential transport, insurance, minimum debt payments. These are your fixed expenses and variable necessities.

30% to wants. What improves your life but isn’t essential: leisure, restaurants, clothes beyond the necessary, treats, entertainment subscriptions, trips. It’s your money to enjoy, guilt-free.

20% to savings and debt. What you put toward building your future: the emergency fund, investing, and paying down debt above the minimums.

The great virtue of 50/30/20 is that it’s easy to remember and apply, and that it reserves explicit space both to enjoy (the 30%) and for your future (the 20%). That simplicity is exactly what makes it sustainable. You can calculate your split instantly with our 50/30/20 Budget Planner, which shows the distribution based on your net salary.

That said, these are indicative percentages, not sacred ones. In expensive cities, needs easily exceed 50%. What matters isn’t nailing the figures, but keeping the three categories in mind and a reasonable target to aim for.

The envelope method

If 50/30/20 splits into three big blocks, the envelope method goes down to the detail by category and is ideal for those who overspend on variable costs. The idea, from the cash era, is to assign each category (groceries, leisure, transport…) a fixed amount per month and “put it in an envelope.” When the envelope empties, that category is done until next month.

Today you don’t need cash: you can do it with separate accounts, prepaid cards by category, or simply an app that warns you when you near each line’s limit. The essence is the same: a clear, visible cap per category that stops you before you overshoot.

Its strength is that it turns control into something physical and concrete. “I have €40 of leisure left this month” is far more actionable than a vague feeling. Its weakness is that it needs more maintenance than 50/30/20. It works wonderfully for the categories where you most lose control; you don’t need to apply it to everything.

Zero-based budgeting

The most demanding and most powerful method. In zero-based budgeting, every euro you earn has an assigned destination before the month begins: income minus allocations equals zero. No “loose” money is left without a function; everything is placed, including savings and even an “envelope” for unexpected costs.

The difference from the other methods is total intention: instead of accepting your current spending and splitting it, you justify each line from scratch, asking what each euro is for. It’s the method that builds the most awareness and where you optimise the most, but also the one that takes the most work. It fits people who like detail or families that genuinely need to tighten for a while. If you’re interested, we cover it in depth in the article Zero-based budgeting.

Adapt it to your reality

Here’s the most important advice in the chapter: no textbook method fits a real family perfectly, and that’s fine. Percentages and rules are scaffolding, not laws. Your job isn’t to obey them to the millimetre, but to use them as a guide and adjust them to your life.

Three principles to adapt them well. First, start simple. If in doubt, begin with 50/30/20: it creates the least friction and the most people sustain it over time. You’ll fine-tune later. Second, start from your reality, not an ideal. A budget built on how you’d like to spend fails; one built on how you actually spend, adjusted little by little, works. Third, prioritise consistency over perfection. An imperfect budget you keep every month is worth infinitely more than a perfect one you abandon in two weeks.

And remember the principle that runs through the whole course: the split isn’t to deprive you, it’s to give you permission. When your leisure has its assigned share, you enjoy it without remorse. When your savings come out first, you stop feeling you “should save more.” A well-made budget doesn’t take away freedom: it organises it.

With a splitting method chosen, you have the skeleton of the budget. In the next chapter we reinforce it with the two pieces that separate a budget that holds from one that breaks at the first surprise: paying yourself first and taming those irregular costs that always, always, end up arriving.