Are card installments a need or a want?

It depends on what you bought, but they're already committed: count them as needs so you don't spend the same money twice.

What if I can't save 20%?

Start with what you can, even 5%. What matters is that it’s automatic and that you raise it over time.

Does it work for couples?

Yes: apply it to the household's income, and each person's personal spending comes out of their share of wants.

Is the 50/30/20 rule based on gross or net income?

Net: what you actually take home after taxes and deductions.

The 50/30/20 rule: how to split your income

By Dionel Azar, creator of Busimy · Updated October 31, 2026

The 50/30/20 rule splits net income into three parts: 50% for needs (housing, food, utilities, transport), 30% for wants (eating out, clothes, travel, subscriptions) and 20% for savings or paying off debt. It's a simple starting point for a budget, not a law: with high rent you almost always need to adapt it.

The three parts

50% needs: what you'd pay no matter what. Rent or mortgage, building fees, utilities, groceries, transport, health insurance, minimum payments.
30% wants: what you choose. Eating out, going out, clothes beyond the basics, travel, subscriptions.
20% savings: emergency fund, investments, or paying debt early.

An example with numbers

With a net income of $5,000 a month: $2,500 for needs, $1,500 for wants and $1,000 to save.

If rent alone is $2,000, needs won't fit in 50%. Then the rule bends: for example 60/25/15, going back to 50/30/20 as income grows.

How to apply it

Work out your monthly net income (what really comes in).
Set savings aside as soon as you get paid, not at the end of the month.
Record a month of expenses and sort them into needs and wants.
Compare with the percentages and adjust where you go over.

How Busimy does it

In Busimy you set budgets per category and savings goals as a percentage of what comes in. Metrics shows how much goes to each category and how much you really saved each month.

The rule with numbers: three incomes

Example amounts. What matters is the share of your net income.
Net income	Needs (50%)	Wants (30%)	Savings (20%)
$2,000	$1,000	$600	$400
$4,000	$2,000	$1,200	$800
$7,500	$3,750	$2,250	$1,500

Where it comes from

The rule was popularized by Elizabeth Warren and Amelia Warren Tyagi in their book "All Your Worth" (2005). The point is not exact percentages but a simple starting point to tell whether your income is well split.

When rent takes more than half

In many cities rent alone takes 40% of income, and with utilities and groceries needs go past 60%. Then you adapt the rule instead of dropping it: 60/25/15 or 70/20/10 is still a plan, as long as savings are not zero.

Frequently asked questions

Are card installments a need or a want?: It depends on what you bought, but they're already committed: count them as needs so you don't spend the same money twice.
What if I can't save 20%?: Start with what you can, even 5%. What matters is that it’s automatic and that you raise it over time.
Does it work for couples?: Yes: apply it to the household's income, and each person's personal spending comes out of their share of wants.
Is the 50/30/20 rule based on gross or net income?: Net: what you actually take home after taxes and deductions.