Build a budget that fits you.
Start from the 50/30/20 rule or a zero-based plan, tweak the targets to your life, and watch your spending line up against them in real time.
Monthly budget builder
Where your money goes
Two ways to build a budget, and when each one fails
A budget is a plan for money you have not spent yet. The two methods here take opposite approaches: one gives you three rough targets and leaves the detail alone, the other insists every dollar has a job. Neither is correct in general, and both break in predictable ways.
The 50/30/20 rule is a starting point, not a law
Half your take-home to needs, 30% to wants, 20% to savings and debt. Its value is that it is memorable and roughly right for a middle income, and it forces a savings target to exist rather than being whatever happens to be left.
It also fails often, and the calculator shows you how. On the example loaded here, needs come to 59% of income, which is $400 over target. That is not unusual. In an expensive housing market the needs share is frequently 60% or more, and when it is, the arithmetic forces the shortfall onto wants or savings.
Zero-based budgeting assigns every dollar
Income minus everything assigned should equal zero. Not zero in your bank account, zero unassigned. Savings is a category you assign to, exactly like groceries, which is the point: money with no job attached tends to find one on its own.
The headline figure on this page is left to budget. Here it reads $650, and that is $650 doing nothing in particular. Zero-based catches this, where a percentage budget would call the same month a success because no target was breached.
The needs and wants line is doing more work than it looks
Rent is a need. Rent on a nicer apartment than you require is partly a want. A car you need to reach work is a need; the trim level is not. Most people classify generously in their own favor, and since the 50% target is measured against that classification, an honest split is what makes the number mean anything.
A usable test: if your income halved next month, would you still pay it? That is a need. Everything else, including subscriptions you forgot you had, belongs in wants. The targets on this page are editable precisely because 50/30/20 does not fit every income, and a deliberately chosen 60/20/20 beats a 50/30/20 you ignore.
The savings rate is the number that predicts your future
Of everything on this page, the savings rate matters most. It determines both how fast wealth accumulates and how expensive the life is that you will need to fund later, so raising it pushes on both ends of the problem at once.
The example here saves 16%, below its 20% target. The gap is not a moral failure, it is information: either income rises, needs fall, or the target was unrealistic. Those are the only three options, and a budget is useful mainly because it forces you to pick one.
What this calculator leaves out
It starts from a single income figure, and the one to use is take-home pay rather than salary. The paycheck calculator works that out, and the debt payoff calculator takes over once the savings and debt bucket has money in it. It works in monthly averages, and real spending is lumpy. Insurance premiums, car registration, holidays and medical bills arrive in bursts, and a budget that balances every average month still fails in the month three of them land together. The usual fix is a sinking fund: divide each irregular annual cost by twelve and treat it as a monthly need.
It also stores nothing and tracks nothing. This is a planning tool, not a ledger, so it cannot tell you whether you followed the plan. That gap is where most budgets actually die, and closing it takes either an app that reads your transactions or the discipline to record them yourself.
Unfamiliar term? The course glossary defines the fifty this site actually uses, in the sense this site uses them.
Common questions
What is the 50/30/20 rule?
A guideline that splits take-home pay into roughly 50 percent needs, 30 percent wants, and 20 percent savings and debt payoff. It is a starting point rather than a rule, which is why the targets here are editable.
What is a zero-based budget?
Every dollar of income is assigned a job until nothing is left unassigned. The goal is not to spend everything, but to decide deliberately where each dollar goes, including the money that goes to savings.
What counts as a need versus a want?
Needs are expenses you cannot reasonably avoid, such as housing, utilities, groceries, transport, and insurance. Wants are discretionary. Groceries are a need, restaurant meals are a want.
What if my needs are more than 50 percent of my income?
That is common in high cost areas, particularly with rent. Treat it as information rather than failure. Adjust the targets to something achievable and look for room in the other two categories.
About the methods: 50/30/20 splits take-home pay into roughly 50% needs, 30% wants, and 20% savings & debt payoff. Adjust the targets to fit your situation. Zero-based means giving every dollar a job until "left to budget" reaches exactly $0. For education and planning only; not financial advice.