A zero based budget assigns the income in a planning period to categories until nothing remains unassigned. Categories can include bills, ordinary spending and amounts reserved for future use. Zero refers to the unassigned amount in the plan, not a required bank balance.
This is one way to describe a budget. The fictional US dollar example below explains its records without prescribing a method, a saving target or category percentages for a household.
Build a fictional monthly plan
Suppose a household expects $4,200 of take-home income for a month. Its example plan assigns $1,500 to rent, $500 to groceries, $250 to utilities, $300 to transport and $350 to other spending.
Those planned expenses total $2,900. The household also assigns $700 to savings and $600 towards future annual bills. The full assignment is $2,900 plus $700 plus $600, which equals $4,200. Income minus assignments equals zero.
No transaction has occurred merely because these amounts were written down. The plan describes intended uses. Actual income receipts, purchases and transfers belong in a separate transaction history so they can be compared with the plan.
The example also does not imply that these amounts fit another household. Housing costs, pay timing, family arrangements and irregular expenses change the inputs.
Separate savings transfers from spending
If the $700 moves from checking to a savings account owned by the same household, the money has changed location. It has not been consumed. A household balance sheet still includes it.
For a budgeting worksheet, the $700 can remain a planned use of income. For a spending report, counting that transfer as an expense and counting the later purchase again would overstate consumption.
The same distinction applies to the $600 reserved for annual bills. Reserving $600 this month and paying a $1,200 bill in a later month are different stages. The worksheet needs to define whether it reports planned allocations, actual purchases or both in separate columns.
A credit card payment introduces a similar recording issue. If each underlying purchase is already recorded as spending, paying the card bill is not another set of purchases. The dates and account references explain the movement without duplicating the expense.
Compare actual amounts with the plan
Now suppose groceries cost $560 rather than the planned $500, with all other example spending unchanged. Actual expenses are $2,960. With the two planned savings assignments still totaling $1,300, the assignments exceed the original $4,200 income by $60.
The difference is visible without calling it an investment loss. It is a $60 gap between the example plan and actual spending. A revised worksheet can show a changed assignment, while the transaction record continues to show the $560 actually spent.
Changing a category target does not change past transactions. Keeping both amounts prevents a plan revised at month end from appearing to have predicted the actual spending perfectly.
Dates and uneven income
A monthly total can balance even when money is unavailable on a bill's due date. A payment due early in the month and income arriving later belong on different dates. The category plan and cash timing answer separate questions.
Irregular bills need dates too. A worksheet that assigns an amount for a future insurance bill can also keep its due date and the amount already reserved. Those records explain the future obligation without recording a purchase before it occurs.
How the records map to FinTarget
FinTarget's Expenses and budgets documentation describes transaction categories and category budgets. These budgets do not create separate savings envelopes or assign every dollar of income.
Income records, expense records and budget targets can describe parts of the example. A separate allocation worksheet retains the $700 and $600 assignments without turning internal transfers into extra spending in the household expense history.