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Budget Calculator

What Is a Monthly Budget Calculator?

A monthly budget calculator maps every dollar of income against every category of spending. Unlike tools that only apply the 50/30/20 rule to a single income number, this calculator lets you enter your actual expenses by category — housing, food, transport, debt, entertainment, savings — so you can see exactly where your money goes, identify overspending, and find where to cut.

How the 50/30/20 Rule Classifies Spending

The 50/30/20 rule, popularized by Elizabeth Warren, divides after-tax income into three buckets. Needs (50%) are non-negotiable essentials: rent or mortgage, groceries, utilities, health insurance, minimum debt payments, and transportation to work. Wants (30%) are lifestyle spending: dining out, streaming, hobbies, and travel. Savings (20%) includes retirement contributions, emergency fund, investments, and debt payments above the minimum. This calculator automatically classifies your expenses into these buckets and shows where you stand.

Questions Fréquentes

Should I use gross income or net income?

Always use net (take-home) income — the amount deposited to your bank after taxes, Social Security, and pre-tax deductions like 401(k). Budgeting on gross income overestimates your actual spending power and causes shortfalls.

What expenses count as Needs vs Wants?

Needs are non-negotiable: rent or mortgage, minimum debt payments, groceries (not restaurants), utilities, health insurance, and transportation to work. Wants are lifestyle choices: dining out, Netflix, gym membership, new clothes, and vacations. Rule of thumb: could you survive without it for 90 days? If yes, it's a Want.

Where do debt payments go in the 50/30/20 rule?

Minimum required payments (credit card minimums, student loan minimum, car payment) count as Needs — they're non-negotiable. Any payments above the minimum count as Savings, because they reduce your liabilities and build net worth faster.

My needs exceed 50% — is my budget broken?

No. In high-cost cities or for families with childcare, 60-70% on needs is common. Use the 60/30/10 framework. The highest-impact lever is usually housing — downsizing, getting a roommate, or moving further from the city can free up $400-$800/month.

How much should I have in my emergency fund?

Standard advice is 3-6 months of essential expenses (needs only, not your full budget). With variable income or as the sole earner in your household, aim for 6-12 months. Keep it in a high-yield savings account (HYSA) earning 4-5% APY, not a checking account.

What is a good monthly savings rate?

10% is the minimum most advisors recommend. 15-20% puts you on track for retirement at 65. 25-35% can enable early retirement in your 50s. The FIRE community targets 50%+ to retire in their 30s-40s. This calculator shows your exact savings rate automatically.