See the gap between income and listed costs
A monthly budget can make a household’s day-to-day cash flow easier to see. Enter after-tax income, living expenses and loan commitments to identify the amount left over, or the amount by which listed costs exceed income.
The value of the exercise depends on the detail entered. Consider converting less frequent bills, subscriptions, insurance, school costs, transport, repairs and seasonal spending into realistic monthly amounts before drawing conclusions. Separating essential costs from discretionary spending may make later review and adjustment easier for the household.
How to read the results
Monthly surplus appears when income exceeds the two expense categories; Monthly shortfall appears when it does not. The primary amount is the absolute size of that difference, with the label explaining its direction.
The three metrics repeat the entered after-tax income, living costs and commitments. The chart annualises the same monthly surplus or shortfall cumulatively; it is not a bank-balance forecast and does not include irregular transactions. Use a conservative estimate where an expense varies, then revisit the inputs as bills or income change.
Worked example
With the default $9,500 monthly after-tax income, $5,200 living expenses and $850 loan commitments, the calculator shows a monthly surplus of $3,450. If each month were identical, the cumulative annual surplus shown by the chart would reach $41,400.
That is an unallocated planning amount, not automatically savings. A household may need to set aside some or all of it for annual bills, emergencies, goals, debt reduction or variable spending.
Assumptions and limitations
- All entered figures are after-tax monthly amounts.
- Living expenses and commitments remain unchanged through the year.
- The annual chart multiplies the same monthly difference by twelve.
- Savings balances, interest earned, debt balances and investment returns are not modelled.
- Unlisted irregular, discretionary and annual costs are excluded until you add them to the monthly inputs.
Frequently asked questions
What should count as a commitment?
Use recurring loan or other fixed commitments that you want separated from general living expenses, without double-counting them.
Why is my annual result different from my bank balance?
The chart only repeats the entered monthly difference. It does not track existing balances, timing, unexpected costs or transfers.
Can a surplus tell me what to do with it?
No. It identifies a planning amount only and does not provide personal financial advice or a recommended allocation.
This calculator and supporting information provide general estimates only. They do not take account of every product rule, tax consequence or personal circumstance and are not financial, tax, credit or legal advice.