What share of income should I save?

A common reference is 10 to 20%. If you can't today, start with what you can and raise it little by little: consistency matters more than the number.

Do card installments go in fixed or variable costs?

Fixed: they are already committed. It helps to know how much you pay in installments each month and until when, before adding new ones.

Does the 50/30/20 rule work?

It is a good starting point (50% needs, 30% wants, 20% savings), but with high rent fixed costs often go over 50%. Adapt it to your numbers.

Household budget: how to make one step by step

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

A household budget takes four steps: add up what comes in each month, list fixed costs, put a cap on variable ones (groceries, eating out, transport) and decide how much to save before spending. Then follow it month by month, comparing what you budgeted with what you really spent.

Step 1: what comes in

Add up the net income of everyone who contributes: salaries, side jobs, rent you collect. If one varies, use a prudent average of the last months.

Step 2: fixed costs

The ones that come every month at about the same amount: rent or mortgage, utilities, internet and phone, insurance, school, subscriptions, card installments.

Write them down with their real amount. If you don't know them, look at the last two or three months of your account and your card.

Step 3: variable costs, with a cap

Groceries, eating out, transport, outings, clothes, gifts. This is where the margin is. Put a cap per category: it doesn't have to be perfect, it has to be realistic.

Step 4: savings first

Decide how much to save at the start of the month, not with what is left at the end (there is rarely anything left). Even 5 or 10% of what comes in: what matters is that it is automatic.

An example with numbers

A family brings in $8,000 a month between two. Fixed costs: $4,400 (rent, utilities, school, insurance). Savings: $800 (10%). That leaves $2,800 for variable costs: $1,800 for groceries, $480 for transport and $520 for outings and other things.

At the end of the month they compare: if groceries came to $2,080, they know they need to adjust there next month, or raise that cap and lower another.

How to follow it without it becoming a chore

Record expenses as they happen, from your phone. By voice or with a receipt photo it takes seconds.
Check the budget once a week: how much you have spent in each category.
Adjust the caps after two or three months, with real numbers.
If you share the home, everyone records: the budget belongs to everyone.

How Busimy does it

In Busimy you set budgets per category and for any period (month, week, year or your own dates), for the household or personal. As expenses come in you see how much is left in each one, and Metrics shows where the money goes month by month and what to expect next month.

Frequently asked questions

What share of income should I save?: A common reference is 10 to 20%. If you can't today, start with what you can and raise it little by little: consistency matters more than the number.
Do card installments go in fixed or variable costs?: Fixed: they are already committed. It helps to know how much you pay in installments each month and until when, before adding new ones.
Does the 50/30/20 rule work?: It is a good starting point (50% needs, 30% wants, 20% savings), but with high rent fixed costs often go over 50%. Adapt it to your numbers.