Quick guide
How to use this calculator
- Enter amounts from one consistent period and currency.
- Set the percentages, limits, and expense basket that match the scenario you want to compare.
- Use the binding limit and component totals to understand the primary result.
Calculation method
Calculation method
Each allocation = after-tax income × its entered percentage; needs + wants + savings percentages must total exactly 100%.
Entered decimals use exact rational arithmetic. Money rounds only for display and a smaller nonzero amount remains visible. Repeating percentages use parentheses; an ellipsis marks a preview longer than 12 places.
Worked example
Worked example
With 4,000 of after-tax income and a 50/30/20 split, needs receive 2,000, wants 1,200, and savings or debt reduction 800.
Each allocation = after-tax income × its entered percentage; needs + wants + savings percentages must total exactly 100%.
Supported inputs
Precision and limits
Visible input limits
Amounts accept up to 30 digits and 12 decimal places and are capped at 1e12. Percentages are 0–100 for these allocation and affordability rules.
International scope
No currency, local price database, tax system, rent rule, benefit, landlord policy, or recommended household allocation is assumed.
Planning boundary
Results compare visitor-entered scenarios and are not financial advice, a housing approval, or a statement that a spending rule is suitable.
Calculator-specific assumptions
50/30/20 is one budgeting convention, not a universal recommendation. The percentages are editable because household constraints differ.