How this works
A monthly budget is just this: what comes in minus what goes out. The hard part is being honest with the numbers. This calculator always works in net, monthly terms, shows the slice each category takes of your income and sets it beside the 50/30/20 rule, a well-known reference for judging whether your split is balanced. We use no rates or official figures that change every year — the numbers are yours.
- 1
Enter your net income
The amount that lands in your account after deductions — income tax and social security. The money you actually have, not gross pay.
- 2
Fill in each category
Rent or mortgage, food, transport, utilities, health, leisure, savings and other. Leave at zero what does not apply.
- 3
Read the balance
The tool totals expenses and shows what is left (or missing) at month end, plus the slice each group takes of your income.
- 4
Compare with 50/30/20
Needs up to 50%, wants up to 30%, savings from 20%. A starting point, not a law — adapt it to your life.
Frequently asked
Gross or net salary?
Net. A budget only makes sense with the money that actually reaches your account, after income tax and social security. Using gross will make the balance look far better than it is. Include allowances and other monthly net income too.
What is the 50/30/20 rule?
A simple way to split net income: up to 50% on needs (rent, bills, food, commuting), up to 30% on wants (leisure, eating out, extras) and at least 20% on savings. In this tool, rent/credit, food, transport, utilities and health count as needs; leisure and other as wants; savings stand on their own.
Is my data stored anywhere?
They never leave your device. Values are kept in your browser local storage so you find them on your next visit. No account, no server, nothing sent anywhere. Clear them with the "Clear" button whenever you want.
How do I handle annual or quarterly bills?
This calculator works per month. For an annual cost (insurance, car tax, property tax), divide by 12 and enter the monthly figure. For a quarterly one, divide by 3. That way the budget reflects the real cost spread across the year, instead of ignoring it for eleven months and getting a shock in the twelfth.
My balance is negative. Now what?
You spend more than you earn. Look first at the biggest slices by percentage: if rent/credit passes 35-40% of net income, that is the most common pressure point in Portugal. Then cut wants before needs. If the deficit persists month after month, it is worth talking to your bank or using Banco de Portugal’s free financial-literacy support.
DISCLAIMER
This tool supports personal planning and only does the arithmetic you enter. The 50/30/20 rule is a general reference, not a legal standard or advice tailored to your situation. It is no substitute for professional financial advice. Values stay in your browser and are not sent anywhere.