Monthly Budget Calculator (Income vs Expenses)

Compare monthly income against fixed and variable household expenses. See what's left, what's missing, and each bucket as a percent of income.

Your month in numbers

Monthly income

Fixed expenses (month)

Variable expenses (month)

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Your result

0/month

Expenses vs income

Pure arithmetic from the numbers you enter. It does not replace a financial plan or professional advice.

What this tool shows

It summarizes the month as: income, what you labeled fixed spending, what you labeled variable, and what remains (or the shortfall). Percentages help you see if a category is heavy relative to inflows.

Wooden desk with notebook, calculator, clipboard, coins and coral mug in soft daylight

Want to situate this monthly balance and use it better day to day?Read the guide →

Why split fixed and variable?

Fixed costs are usually harder to cut quickly (rent, loans, subscriptions). Variable costs swing more month to month (dining, shopping). Splitting helps you decide where to act first when you need to adjust.

How to think about the buckets

You choose what goes in each box; the calculator only adds:

Fixed: amounts that repeat every month at about the same level.
Variable: spending that fluctuates or depends on habits.
Balance: income minus fixed minus variable; positive means surplus on paper, negative means these inputs exceed income.

Practical tips

Use realistic figures; underestimating expenses creates a misleading positive balance.
If balance is negative, either income in the model is too low for the month or spending needs review.
Percentages only make sense when income is greater than zero; at zero income the tool does not compute %.

Limitations

It does not categorize transactions, import statements, or suggest cuts. It is a one-off snapshot from what you type, not a continuous budgeting app.

Formulas

Balance is income minus the sum of expenses. When income is positive, each percentage is (category ÷ income) × 100.

balance = income − fixed − variable
% of income = (amount ÷ income) × 100balance=i−f−vpct=ai×100\begin{aligned}\text{balance}&=i-f-v\\\text{pct}&=\dfrac{a}{i}\times100\end{aligned}balancepct​=i−f−v=ia​×100​

FAQ

How should I read the percentages?

Each shows what share of income went to that category in this snapshot. For example, 40% fixed means almost half of income went to what you marked as fixed.

What if the balance is negative?

It means expenses exceed income with these inputs. Review amounts or planning. The tool only subtracts what you type.

Is this financial advice?

No. It is a simple snapshot from your figures.