> ## Documentation Index > Fetch the complete documentation index at: https://docs.guito.pt/llms.txt > Use this file to discover all available pages before exploring further. # How cash flow works > How guito aggregates income and expenses over time. Cash flow shows where your money went: how much came in, how much went out, and how it changed over time. guito builds this view from the movements in your bank accounts, grouped by category and by period. You'll find it under **Cash flow** (`/transactions`). This page explains how those numbers are calculated, so you always understand where each total comes from. You don't need to know any of this to use guito. This is for anyone who wants to understand the logic behind the income, expense, and balance figures shown on the Cash flow page. To act on your movements (filter, recategorize, link a transfer, exclude a movement), see [Transactions and cash flow](/en/features/transactions). Cash flow relies on bank accounts connected through automatic sync (open banking). Without connected accounts, there are no movements to analyze. See [Bank sync](/en/features/bank-sync) to get started. ## The amount sign decides the direction The core rule is simple: the sign of each movement determines which side of the analysis it lands on. * Positive amount: money that came in (income side). * Negative amount: money that went out (expense side). This rule applies everywhere: in the header totals, the monthly chart, the category breakdown, and the colors in the movement list. The header totals reflect what actually came in and went out: * Income: the sum of all movements with a positive amount. * Expenses: the sum of the absolute value of all movements with a negative amount. * Balance: the difference between the two. ## The category is a label, it doesn't pick the side A movement's category (for example, "Rent" or "Salary") helps you organize and read your data, but it does not decide whether the movement counts as income or expense. The amount sign decides that. You can assign any category to any movement. A 700 € reimbursement filed under "Rent" appears on the income side, because the amount is positive. A 200 € debit filed under "Salary" appears on the expense side, because the amount is negative. Both are valid choices. The same category can appear on both sides when it has movements in both directions. For example, if you paid 1,400 € in rent and received a 700 € reimbursement from someone you share a home with, the "Rent" category shows 1,400 € on the expense side and 700 € on the income side, leaving the real cost visible. ## What's left out of the analysis So that totals reflect only money that actually came in or went out, guito leaves out two kinds of movements: * **Matched internal transfers.** When you move money between your own accounts, that amount is neither income nor expense, it's the same money changing places. When guito is confident two movements are a pair (same amount, opposite signs, close in time), it links them and excludes both from the totals. * **Movements excluded from cash flow.** You can manually mark a movement to stop it counting toward income and expense totals. It stays visible in the list, with a minus-circle icon, but it doesn't enter the sums. Cash-flow breakdowns (totals, the monthly chart, and categories) do not include matched internal transfers or excluded movements. If a total looks lower than you expected, check whether some movements have been linked as a transfer or marked to be excluded. ## When you adjust the analysis yourself Most transfers are linked automatically. When guito cannot be sure two movements are a pair, it leaves them unlinked rather than guess, and you stay in control of what counts. You can link the two sides of a transfer between your own accounts by hand, so the pair drops out of the totals, and you can exclude any single movement (for example, a technical bank entry) that shouldn't count toward the analysis. An excluded movement stays visible in the list but doesn't enter the sums, and you can include it again at any time. The step-by-step for both lives in [Transactions and cash flow](/en/features/transactions). ## The role of categories Each movement is given a category automatically from the bank data, and you can adjust it whenever you want. Categories don't change which side a movement falls on, but they are the basis for the breakdown, so a correction is what makes the per-category totals match how you actually think about your spending. To understand how categories are assigned and corrected, see [Automatic categorization](/en/concepts/automatic-categorization). For analysis by category or by merchant, you can also ask guito's assistant questions like "Where do I spend the most money?" or "How much did I spend on restaurants this month?". The assistant reads the same categorized movements and can filter by period (week, month, quarter, or year). ## Dates and time zone Each transaction shows the calendar day the bank recorded, regardless of the time zone you're in. A user in the Azores, in Lisbon, or in Tokyo always sees the same day for the same transaction: the day on the bank statement. ## Currency All totals are shown in euros. Movements in a foreign currency are converted to euros before they enter the sums, so the math makes sense even with accounts in different currencies. ## Related pages View, filter, recategorize, and adjust your bank movements. Why transfers between your own accounts don't count as income or expense. How to connect your accounts through open banking to feed cash flow. Track subscriptions, rent, and salaries that repeat every month.