Look at a representative period
Collect a few months' income and expenses, including cash payments and automatic debits. A single month can be deceiving: a holiday, a refund or an unusual bill changes the outcome. Start from the net revenue actually available; an occasional entry should not be treated as if it were always repeated.
If the income is variable, separate the proceeds already received from those expected. It can also be useful to build a prudent scenario: ask yourself what expenses you would be able to bear in a less favorable month.
Separate expenses by function
The categories must be few and understandable. The important distinction is between what recurs, what changes and what only arrives at certain times of the year.
| Category | Examples | How to read it |
|---|---|---|
| Appellants | Rent, installments, subscriptions | Check debit amounts and dates. |
| Variables | Food, transport, leisure | Observe the average and the fluctuations. |
| Periodicals | Insurance, maintenance | Distribute the cost over the available months. |
A hypothetical annual expense of €600 equates to a fee of €50 per month if you have twelve months to prepare. If the deadline is in three months and you have not already set aside anything, the requirement is instead €200 per month. The date matters as much as the amount.
Calculate the margin, without judging it
Subtract current expenses and allowances for future commitments from your income. The result is a theoretical margin: it is not automatically money to invest. You may have to allocate it to unexpected events, debts or nearby goals. If it is negative, check the missing items and deadlines first; then identify which commitments can be changed.
Your monthly margin
An arithmetic simulation, without recording. Use monthly amounts and don't count the same expense twice.
Review the balance sheet when life changes
A change of job, a move or a new installment makes previous hypotheses old. Compare forecast and result periodically, without seeking impossible precision. The aim is to recognize deviations and decide with better information, not to respect universal percentages.
The next step
Give purpose to available margin ↗