Quick answer
Money left over = income − (housing + food + transport + utilities + other). With $4,500 income and $2,800 of spending, $1,700 (37.78% of income) is left each month.
Enter monthly income and the spending categories. The calculator returns the amount left and the share of income. Use this budget calculator to check your own figures.
Related tools: College Cost Calculator: Projected total cost of study with yearly cost inflation. Net Worth Calculator: Total assets minus total liabilities. Gift Budget Calculator: Spending per recipient after a reserve.
How to use the Budget Calculator
- Enter monthly income ($) (above 0).
- Enter housing ($) (0 or more).
- Enter food ($) (0 or more).
- Enter transport ($) (0 or more).
- Enter utilities ($) (0 or more).
- Enter everything else ($) (0 or more).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Monthly income | A number, in $ | > 0 |
| Housing | A number, in $ | ≥ 0 |
| Food | A number, in $ | ≥ 0 |
| Transport | A number, in $ | ≥ 0 |
| Utilities | A number, in $ | ≥ 0 |
| Everything else | A number, in $ | ≥ 0 |
Formula and method
Formula
left over = income − (housing + food + transport + utilities + other)
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
A simple monthly cash-flow check.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Monthly income = 4500; Housing = 1400; Food = 500; Transport = 350; Utilities = 250; Everything else = 300.
| Result | Value |
|---|---|
| Left over each month | $1,700.00 |
| Total spending | $2,800.00 |
| Left over (% of income) | 37.7778% |
Example 2
Inputs: Monthly income = 3000; Housing = 1800; Food = 600; Transport = 400; Utilities = 300; Everything else = 200.
| Result | Value |
|---|---|
| Left over each month | -$300.00 |
| Total spending | $3,300.00 |
| Left over (% of income) | -10% |
The first line is the headline result (left over each month). Below it the budget Calculator lists total spending and left over (% of income), which describe the same case from other angles. IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice.
Reading the percentage
37.78% left is a high savings capacity. A popular guide, the 50/30/20 rule, suggests 50% on needs, 30% on wants and 20% on saving and debt repayment. Here housing is 31% of income.
Negative balances
A negative result means spending exceeds income. Reduce the largest flexible category first, such as food or other spending, or increase income. Review actual statements, as people often underestimate small spending.
How the result changes with monthly income
Holding every other input at the first worked example, this table changes only monthly income. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Monthly income | Left over each month | Total spending | Left over (% of income) |
|---|---|---|---|
| 2250 | -$550.00 | $2,800.00 | -24.4444% |
| 4500 | $1,700.00 | $2,800.00 | 37.7778% |
| 9000 | $6,200.00 | $2,800.00 | 68.8889% |
| 18000 | $15,200.00 | $2,800.00 | 84.4444% |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Monthly income: entering "0" shows "Monthly income must be greater than 0." beside that field and no result.
- Housing: entering "-1" shows "Housing must be at least 0." beside that field and no result.
Choosing between the Budget Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [College Cost Calculator](/finance/college-cost-calculator/) | annual cost today, years until study starts and annual cost increase | Projected total cost |
| [Net Worth Calculator](/finance/net-worth-calculator/) | assets and liabilities | Net worth |
| [Gift Budget Calculator](/lifestyle/gift-budget-calculator/) | total budget, recipients and held in reserve | Per recipient |
| [Travel Budget Calculator](/lifestyle/travel-budget-calculator/) | trip length, lodging per night and food per day | Total trip cost |
| [Food Waste Percentage Calculator](/cooking/food-waste-percentage-calculator/) | food wasted and total food | Food waste |
Background: personal finance estimates
Financial calculators project from the numbers you give them. Long-range tools depend on guesses about returns and tax rates that are unlikely to hold exactly, payoff tools assume a fixed payment and rate, and tax or salary results depend on the tax year, filing status and country. Official calculators say their output is for reference only.
For decisions that matter, use conservative inputs and check the figures against your lender, plan documents or a qualified adviser.
Assumptions and limitations
- Negative result means spending exceeds income
Results are estimates for planning, not financial advice. Lender terms, fees, taxes and rounding rules can change real figures, so confirm important numbers with your lender or a licensed adviser.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for monthly income and housing to confirm this.
Frequently asked questions
How much should I spend on housing?
A common guideline is up to 30% of income.
Should irregular costs be included?
Yes, average them by month.
Does it include taxes?
Use take-home income.
What does the Budget Calculator calculate?
Monthly income minus spending, and the share left over. It returns Left over each month, Total spending and Left over (% of income).
What formula does the Budget Calculator use?
left over = income − (housing + food + transport + utilities + other). A simple monthly cash-flow check.
What do I need to enter in the budget Calculator?
You enter Monthly income ($), Housing ($), Food ($), Transport ($), Utilities ($) and Everything else ($).
How is the result rounded or limited?
IEEE-754 double precision; money shown to cents, rates to 4 decimals. Results are estimates, not financial advice. Negative result means spending exceeds income.
What is an example of a budget result?
With monthly income 4500, housing 1400, food 500, transport 350 and utilities 250, the left over each month is $1,700.00.
Can I rely on this calculator for a decision?
Results are estimates for planning, not financial advice. Lender terms, fees, taxes and rounding rules can change real figures, so confirm important numbers with your lender or a licensed adviser. For this calculator in particular: Negative result means spending exceeds income.
Related calculators
- College Cost Calculator — Projected total cost of study with yearly cost inflation.
- Net Worth Calculator — Total assets minus total liabilities.
- Gift Budget Calculator — Spending per recipient after a reserve.
- Travel Budget Calculator — Total trip cost from daily and one-off costs.
- Food Waste Percentage Calculator — Share of food that was wasted.
- Portion Size Calculator — Amount of food per person.
Sources
- Standard time-value-of-money relations (e.g. Brealey, Myers & Allen, Principles of Corporate Finance)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.