Budget Calculator

Build a monthly budget by category and see your surplus against the 50/30/20 rule.

About Budget Calculator

The 50/30/20 rule provides a quick benchmark: 50% of after-tax income to needs (housing, food, transportation, insurance, minimum debt payments), 30% to wants (dining, entertainment, hobbies), and 20% to saving and debt repayment above minimums. It's a guideline, not a law — high-cost-of-living cities may require different splits. The key output is the monthly surplus: if it's positive, you have room to accelerate savings; if negative, you need to cut spending.

Formulas

50/30/20 targets

Needs ≤ 50% of income, Wants ≤ 30%, Savings ≥ 20%

I: Monthly after-tax income

Monthly surplus

Surplus = Income − (Needs + Wants + Savings)

N: Total needs spending
W: Total wants spending
S: Total savings and extra debt payments

Worked example

With the default values below, Budget Calculator returns Monthly Surplus / (Deficit) of $1,000.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Monthly After-Tax Incomeminimum 0 $: 5,000 $
Housing (rent / mortgage)minimum 0 $: 1,400 $
Utilitiesminimum 0 $: 150 $
Groceries & Food at homeminimum 0 $: 400 $
Transportation (car, transit)minimum 0 $: 350 $
Insurance (health, auto, life)minimum 0 $: 250 $
Minimum Debt Paymentsminimum 0 $: 200 $
Other Needsminimum 0 $: 0 $
Dining Out & Takeoutminimum 0 $: 250 $
Entertainment & Subscriptionsminimum 0 $: 100 $
Clothing & Personal Careminimum 0 $: 100 $
Travel & Vacationsminimum 0 $: 100 $
Other Wantsminimum 0 $: 0 $
Retirement Savings (401k, IRA)minimum 0 $: 500 $
Emergency Fundminimum 0 $: 100 $
Extra Debt Paymentsminimum 0 $: 100 $
Other Savings / Investmentsminimum 0 $: 0 $

Results

Monthly Surplus / (Deficit)Positive means money left over; negative means you are spending more than you earn.: $1,000.00
Total Monthly Expenses: $4,000.00
Needs: $2,750.00
Wants: $550.00
Savings & Debt: $700.00
Needs (%): 55.0%
Wants (%): 11.0%
Savings (%): 14.0%

Step by step

1Monthly after-tax income= $5,000.00
2Needs= $250.00 over
3Wants= $950.00 under
4Savings & Debt= $300.00 under target
5Monthly surplus (unallocated)= $1,000.00

Assumptions and limits

The result is derived only from the 17 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What counts as a 'need' vs a 'want'?

Needs are non-negotiable expenses required to live and work: rent/mortgage, utilities, basic food, health insurance, minimum debt payments, and transportation to your job. Wants are lifestyle choices you could reduce if necessary: dining out, subscriptions, travel, hobbies. The line isn't always clear — a car can be a need in some cities and a want in others.

The 50% needs target feels impossible in my city. Is the rule broken?

In high-cost cities (San Francisco, NYC, London), housing alone can exceed 40% of income. Many financial planners adapt the rule to 60/20/20 or 65/20/15 when costs force it. The key is still to track all three buckets and maximise savings within your constraints.

Where should my surplus go?

First: build 3–6 months of expenses as an emergency fund. Second: maximise employer 401(k) match (it's an instant 50–100% return). Third: pay off high-interest debt (above ~6% APR). Then invest in tax-advantaged accounts (Roth IRA, maxing 401k). Only after those should you invest in taxable accounts.

Should I use gross or net income?

Net (after-tax) income. The 50/30/20 rule is meant to be applied to take-home pay — money you can actually spend. Gross income includes taxes you never see. Enter the amount deposited to your bank account each month.