Budget calculator
Monthly Budget Calculator
See how your monthly income compares with fixed bills, debt payments, savings, and flexible spending.
How this calculator works
This budget calculator adds your planned monthly outflows and compares them with take-home income. It is designed for quick planning, not account-level bookkeeping.
The formula
monthly cash left = take-home income − housing − other fixed bills − debt payments − savings − flexible spending
Two derived numbers round out the picture: savings rate = savings ÷ income, and needs share = (housing + other fixed bills + debt payments) ÷ income. These let you compare your allocation against common guidelines like 50/30/20.
Worked example
On a take-home income of $5,200 with housing $1,850, other bills $900, debt $450, savings $650, and flexible spending $950, total outflow is $4,800 and cash left is $400. The savings rate is $650 ÷ $5,200 ≈ 12.5%, and the needs share is $3,200 ÷ $5,200 ≈ 61.5% — slightly above the 50% guideline, which suggests looking for savings in the needs or flexible categories.
The 50/30/20 guideline
The 50/30/20 rule is a simple allocation framework popularized by Senator Elizabeth Warren in All Your Worth:
- 50% needs — housing, utilities, groceries, insurance, transportation, minimum debt payments
- 30% wants — dining out, entertainment, travel, hobbies
- 20% savings & debt — retirement contributions, extra debt payments, emergency fund
It's a benchmark, not a law. High-cost-of-living areas often push needs above 50%, and lower-income households may struggle to reach 20% savings. The calculator's "needs share" and "savings rate" outputs exist so you can see where you stand.
How to use the result
If the result is negative, planned spending exceeds income — start by reviewing flexible spending, subscriptions, and debt strategy, or look for income opportunities. If the result is positive, assign the surplus deliberately: emergency savings, extra debt payoff, or a specific goal. Money that is not assigned a job tends to get spent.
Related tools & guides
- Read How to build a simple monthly budget for a step-by-step method.
- Setting a lease target? Read How much rent can I afford?
- Decide where your savings go with the Savings Goal Calculator.
- Attacking debt from this budget? Use the Debt Payoff Calculator.
Frequently asked questions
What is the 50/30/20 budget rule?
Roughly 50% of take-home pay to needs, 30% to wants, and 20% to savings and debt. This calculator shows your needs share and savings rate so you can compare.
What is a good savings rate?
A common benchmark is 20% of take-home pay, but any positive rate is a good start. The calculator shows your current rate so you can track it over time.
Should the budget use gross or net income?
Net (take-home) income, because that's the money actually available to allocate after taxes and payroll deductions.
What if my monthly cash left is negative?
Spending exceeds income. Review flexible spending, subscriptions, and debt strategy, or look for ways to raise income.
Important note
This page provides educational estimates only. It is not financial, tax, legal, or investment advice. See our disclaimer.