Building a monthly budget

Comparing monthly inflows and outflows without mixing flows and wealth.

How a monthly budget works

A monthly budget compares what comes in (salary, income, refunds) with what goes out (housing, groceries, transport, subscriptions…) over a month. The difference shows what is left to save or to cover unexpected expenses.

Key takeaway

A budget looks at the flows of a month; wealth looks at what you own on a given date.

Simple categories

A few broad categories are often enough to see where money goes: fixed costs (housing, energy, insurance, subscriptions), everyday spending (food, transport) and one-off spending. Comparing several months helps tell an exceptional expense from a trend.

Budget and wealth

A transfer to your savings account or brokerage account is not an expense: the money simply changes account. Between two accounts tracked in the budget, PortefeuilleZen treats it as a neutral internal transfer; to a savings or investment account outside the budget, it shows as savings, never as consumer spending. Money coming in is never counted as income by default: an unqualified incoming transfer stays "to categorise".

Your bank labels

Bank transaction labels often contain sensitive data (name and IBAN of a counterparty, masked card number, references). PortefeuilleZen cleans them before anything is stored and keeps only a readable label (for example "Transfer received"), never the raw text.

Attention

PortefeuilleZen describes your flows; it makes no recommendation on how to spend or save.

Updated on September 25, 2026 · These pages are purely informational: PortefeuilleZen never provides personalized buy, sell or allocation advice.