How this calculator works
A budget compares the money coming in each month with the money going out. This calculator takes take-home pay, the amount left after income tax and payroll deductions, and subtracts spending in each category plus whatever you set aside as savings. The leftover figure is what remains unallocated: a positive number is money you have not assigned a job, and a negative number means the plan spends more than you earn. Each category is also shown as a share of income, which makes it easy to spot a category that has quietly grown. Housing is the largest line for most households, and a common guideline is to keep shelter costs, including utilities for some definitions, at or below about 30% of gross income. Food, transport and insurance follow. The category list is fixed so that the shares can be compared from month to month; put anything that does not fit into Other spending. Savings is shown separately because it is money you keep rather than money you spend.
Formula
Total spending = sum of all spending categories. Leftover = income - total spending - savings. Spending share = total spending / income. Savings share = savings / income. A negative leftover means the budget is overspent by that amount.
Worked example
On $6,000 of take-home pay, the default categories add to $4,500 of spending: $1,800 housing, $250 utilities, $700 food, $450 transport, $150 health, $200 insurance, $400 debt payments, $0 child care, $300 entertainment and $250 other. With $600 going to savings, $900 is left over. Spending is 75.00% of income and savings is 10.00%.
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Frequently asked questions
Should savings count as an expense?
It is money you keep rather than spend, so this calculator shows it on its own line and excludes it from total spending. Either way, it must come out of income before the leftover is calculated.
Why is my leftover negative?
The categories and savings add to more than your take-home pay. The usual fixes are to cut a discretionary category, refinance a fixed cost, or raise income. A negative leftover is a warning, not an error in the arithmetic.
Should I budget from gross or net pay?
Net pay. Income tax and payroll deductions are already gone, so budgeting from gross pay would overstate what is available. If you are self-employed, use an average of the amount you can draw each month.
How often should I update the budget?
Once a month is enough for most people. Compare the actual amount in each category with the plan, then adjust the next month. Quarterly reviews catch seasonal costs such as heating or back-to-school spending.
What about annual costs like insurance or car repairs?
Divide the annual amount by twelve and include that monthly figure. Setting the money aside every month avoids a large bill landing in a month that cannot absorb it.