How much of your income can go to debt: what the sources say

Before taking on a new instalment, one question helps: how much of your monthly income is already committed to debt? The calculation is a simple division, but the numbers quoted to read it, such as 30%, 36% or 40%, come from sources of very different kinds, and none of them is law. This guide explains the calculation, where each level comes from and what it does not say. The examples use reais, dollars and euros.

How income commitment is calculated

Add up everything that goes out each month to pay debts: the financing instalment, the loan, the card minimum, what the payroll loan takes off your pay. Divide by monthly income. If the sum is R$ 900.00 and income is R$ 5,000.00, the commitment is 18%. With a new instalment of R$ 700.00, the sum becomes R$ 1,600.00 and the commitment 32%.

Two choices change the result: which payments are counted and which income is used. Gross income is the one before taxes and deductions; net income is what reaches your account. The same payment is a larger slice of net income than of gross, which is why a level measured on gross income cannot be compared with a percentage calculated on net.

The levels that sources quote

In Brazil there is no norm and no official page: banks and credit portals say they usually accept an instalment of up to about 30% of gross income, and that is what Finasst shows, described as market practice. In the United States the CFPB publishes a debt-to-income tool inside a financial education toolkit: for homeowners it suggests keeping all debts at 36% or less of gross income and acknowledges that some lenders go to 43% or higher. The same tool quotes 15% to 20% for renters, leaving rent out. In Spain the Banco de España calculates, in its Survey of Household Finances, the ratio of debt payments to the household's gross income and counts the indebted households above 40%; it is a statistical measure, and the document does not recommend a limit.

An example with numbers

With gross income of R$ 5,000.00 and Brazil's 30% reference, the level is R$ 1,500.00 a month in debts. Someone already paying R$ 900.00 is at 18%, within the reference, and has room for one more instalment of up to R$ 600.00. An instalment of R$ 700.00 takes the total to R$ 1,600.00, or 32%: past the reference, by R$ 100.00. Being exactly at R$ 1,500.00 counts as within; one cent more counts as above.

In the United States, with US$ 5,000.00 of gross income, the 36% level is US$ 1,800.00. Someone paying US$ 2,300.00 a month is at 46%, above both the 36% level and the 43% one. In Spain, with € 3,000.00 of gross income, 40% is € 1,200.00: payments of € 1,200.00 are exactly on the statistic's threshold, and with € 1,260.00 the ratio is 42%.

What the central bank's indicator shows

Every month the Banco Central do Brasil publishes the share of household income committed to debt service with the financial system (series 29034 of its time-series system). In August 2026 it stood at about 29%. It is a measure of the whole country, calculated over households together and as a three-month average: it describes how much of the country's income goes to debt service and it is not a limit, either for the country or for one household. Saying "the average is 29%" does not say what is adequate for the person reading.

What the calculation does not see

A percentage of income leaves out whatever is not debt. Before deciding, weigh these too:

• Other expenses. Rent, building fees, food, health and transport come out of income before anything is left for instalments. The amount left that the page shows is before them.
• Income that varies. For irregular income, a good month misleads. Use a typical month, and lean towards estimating low.
• The household's income. Levels usually speak of household income. Add only that of the people who actually share the expenses and the payments.
• An instalment that changes. In a SAC contract the first instalment is the largest, and Finasst uses that one in the simulation. Instalments with variable interest can rise.
• What a lender looks at besides income. Credit analysis usually also considers payment history and collateral, and lenders have different limits. A level quoted by a source does not say whether anyone would approve the loan.

How Finasst calculates it

On the Income commitment page, enter your monthly income, what you already pay each month in debts and, if you want, the instalment you are considering; if you have an account you can add the next instalment of your saved contracts. The result appears at once, with no account needed and no simulations spent: today's percentage and the one after the instalment, what is left of the income, the largest instalment that fits the reference and, beside them, the source of the level and what kind of source it is. The same panel appears in the simulation, with the largest instalment of the simulated contract, and in My debts. The income you type stays only in the device's memory: it is not sent or kept, and it goes when you reload the page. If you have several debts, the exit plan page shows the order to pay them in. The page describes what the calculation shows and does not recommend taking a loan or not taking it.