Quick guide
How to use this calculator
- Choose one time period and one currency, then enter every amount using that same basis.
- Use zero when a listed category does not apply; do not leave required fields empty.
- Read the primary result together with its component totals and the visible scope notes.
Calculation method
Calculation method
Category-to-income ratio = selected expense ÷ income; category-to-spending ratio = selected expense ÷ total spending.
Entered decimals are combined with exact integer-and-rational arithmetic. Results round to two decimal places for ordinary money display, while a smaller nonzero value remains visible instead of being shown as zero. Repeating percentage digits appear in parentheses; an ellipsis marks a decimal expansion longer than the 12-place preview.
Worked example
Worked example
A 900 category within 3,000 of total spending and 4,000 of income is 22.5% of income and 30% of spending.
Category-to-income ratio = selected expense ÷ income; category-to-spending ratio = selected expense ÷ total spending.
Supported inputs
Precision and limits
Visible input limits
Amounts accept up to 30 digits and 12 decimal places and are capped at 1e12 in magnitude. Scientific notation and grouped thousands separators are rejected.
International scope
No currency, tax system, benefit definition, debt limit, accounting standard, or recommended household ratio is assumed.
Planning boundary
The result is a mathematical summary of entered amounts, not financial advice, a credit decision, a tax calculation, or a legal balance sheet.
Calculator-specific assumptions
All three values must use the same period and currency. This household-spending ratio is not an investment-fund expense ratio.