Budget Calculator
Create a personal monthly budget, track income vs expenses by category, and see how your spending compares to the 50/30/20 rule.
How It Works
Enter your monthly take-home income and list your expenses grouped into Needs, Wants, and Savings. The calculator totals each category, shows your surplus or deficit, and compares your actual spending against the popular 50/30/20 budgeting rule.
Formula
Surplus/Deficit = Monthly Income − Total Expenses
Category % = (Category Total ÷ Monthly Income) × 100
Each expense is tagged as Needs, Wants, or Savings. The calculator sums each category and expresses it as a percentage of your monthly net income, then compares that percentage against the 50/30/20 targets.
Worked Example
Budgeting a $4,500 monthly take-home income
- Monthly net income: $4,500
- Needs (rent, groceries, utilities, insurance, transportation): $2,550 → 56.7% (target: 50%)
- Wants (dining out, entertainment, shopping): $450 → 10% (target: 30%)
- Savings (emergency fund, retirement): $500 → 11.1% (target: 20%)
- Total expenses: $3,500 → Surplus: $1,000/month
- This household is under-allocating to Savings relative to the 50/30/20 target — a good use for the $1,000 surplus
Common Mistakes
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Budgeting based on gross income instead of take-home pay
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Always budget using your net income (after taxes and payroll deductions) — budgeting against gross salary overstates how much money you actually have to allocate.
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Not accounting for irregular expenses
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Annual or quarterly expenses (car registration, insurance premiums, gifts) are easy to forget in a monthly budget. Divide them by 12 and add a line item so they don't catch you off guard.
