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HoldingCost

Budget split calculator

Allocate your monthly income across needs, wants, and savings using the 50/30/20 rule or a custom split.

Calculator personal

Logic updated April 2026

This calculator allocates your monthly income across three categories — needs, wants, and savings — using either the popular 50/30/20 rule or a custom percentage split. The output shows the dollar amount for each bucket and flags any over- or under-allocation so you can rebalance until the percentages add to 100%.

How this is calculated

Formula 

needsAmount = income × needs% / 100 ; wantsAmount = income × wants% / 100 ; savingsAmount = income × savings% / 100

Step-by-step

  1. Take your monthly income figure as the starting point
  2. Multiply by the needs percentage and divide by 100 to get the needs allocation in dollars
  3. Repeat for the wants and savings percentages
  4. Sum the three amounts — if the total is below your monthly income, the gap is unallocated and surfaced as a warning
  5. If the percentages add to more than 100%, the calculator flags an over-allocation so you can reduce one or more categories
  6. The default 50/30/20 split allocates 50% to needs, 30% to wants, 20% to savings — adjust to match your priorities
Rounding mode
ROUND_HALF_UP
Precision
20-digit internal precision (Decimal.js), rounded to 2 decimal places for display
Logic last reviewed

Assumptions & limitations

What this calculator assumes

  • Percentages apply to monthly income
  • Percentages summing above 100% are flagged with a warning but allowed
  • Three categories: Needs, Wants, Savings
  • Income is treated as net (after-tax) take-home — adjust if you're using gross

What this calculator doesn’t account for

  • Doesn't model irregular income — uses a single monthly figure
  • Doesn't categorise individual expenses for you
  • Doesn't account for one-off costs (annual insurance, holidays) — fold those into a savings sub-bucket
  • Doesn't model varying tax or deduction rates by jurisdiction
  • The 50/30/20 split is a guideline, not a tested rule for every income level

Worked example

A household has $5,000 of monthly take-home income and applies the 50/30/20 rule.

Input Value
Monthly income $5,000
Needs 50%
Wants 30%
Savings 20%

Needs: $2,500 — Wants: $1,500 — Savings: $1,000

$5,000 × 50% = $2,500 for housing, food, transport, utilities, insurance, and minimum debt payments. $5,000 × 30% = $1,500 for discretionary spending. $5,000 × 20% = $1,000 for savings, investments, and extra debt repayment. Total: $5,000, fully allocated. If your needs in a high-cost area realistically take 60%, drop wants to 20% or savings to 10% to keep the total balanced.

Frequently asked questions

What is the 50/30/20 rule?

A budgeting heuristic popularised in the book 'All Your Worth' (2005). It allocates 50% of after-tax income to needs (housing, food, utilities, transport, minimum debt payments), 30% to wants (entertainment, dining out, subscriptions), and 20% to savings (emergency fund, retirement, investments, extra debt repayment). It's a starting point, not a one-size-fits-all rule.

How do I adjust the split for high-cost areas?

If housing alone takes 35%+ of your income, the 50% needs bucket is already overspent before you've added utilities or transport. Common adjustments: 60/20/20 in high-cost-of-living areas, or 70/20/10 if rent and essentials genuinely consume 70%. The savings rate is the lever you most want to protect — going below 10% makes long-term wealth-building very slow.

What counts as needs vs wants?

Needs are things you'd struggle to cut without changing your life materially: housing, electricity, basic groceries, work transport, insurance, minimum debt repayments. Wants are things you'd miss but could live without: streaming services, dining out, holidays, premium subscriptions. The grey zone (a gym membership, a car upgrade) is yours to classify — be honest about which is which.

Is 50/30/20 realistic on a low income?

On lower incomes, needs typically consume more than 50% of income — often 70–80%. The mathematical alternative is to either grow income or move costs down (cheaper housing, lower transport, fewer subscriptions). Even 5% to savings on a low income is meaningful — the rule's split is aspirational; the discipline of always saving something is what actually builds wealth over time.

Should I use gross or net income?

Net (after-tax) income, because that's what you actually have to allocate. Using gross will give you bigger-looking numbers in each bucket but the categories won't add up to your real take-home pay. If you only know your gross figure, subtract an estimate of taxes and mandatory deductions before plugging into the calculator.

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