Budget Calculator

How a monthly budget works:

A budget is the simplest and most powerful personal finance tool. It compares your total income against your total expenses to show whether you are saving money or overspending.

The formula:

Monthly Savings = Total Income − Total Expenses

The 50/30/20 rule (recommended budget split):

Worked example:

Monthly income: $4,000 after tax

• Needs (50%): $2,000: rent $1,200, groceries $400, utilities $200, insurance $200
• Wants (30%): $1,200: dining $300, entertainment $200, subscriptions $100, shopping $600
• Savings (20%): $800: emergency fund $400, retirement $400

If your expenses exceed income:

1. First cut wants, subscriptions, dining out, shopping
2. Then reduce needs, cheaper housing, lower grocery bill, shop for better insurance rates
3. Then increase income, side hustle, negotiate a raise, freelance work

Key tip: Track your actual spending for one month before making a budget. Most people are surprised where their money really goes, because small daily purchases add up to hundreds a month without ever feeling like a decision.

Emergency fund target: Save 3–6 months of essential expenses before investing. This protects you from unexpected job loss, medical bills, or car repairs.

Where the 50/30/20 rule breaks down

It was written by Elizabeth Warren in 2005, when housing took a smaller share of income than it does now. In an expensive city, rent alone can be 40% of take-home pay, and hitting 50% for all needs is not a discipline problem, it is arithmetic. If that is your situation the rule is still useful, just read it differently: the 20% savings line is the one to defend, and the 30% wants line is where the squeeze has to land.

The other common mismatch is variable income. If you are paid by commission or freelance, budget against your worst recent month rather than your average, and treat everything above that as a savings month rather than a spending one.