Enter your monthly income, assign it to categories, and get the 'left to assign' number to exactly zero. This is the whole method — live, in your browser.
Expense trackers tell you what happened — an autopsy. Zero-based budgeting decides what will happen — a plan. The psychological shift is subtle but decisive: when the takeaway money is gone, the question isn't "can I afford this?" (the answer always feels like yes) but "which envelope pays for this?" — a question with an honest answer. It's the same reason the cash-envelope system worked for our grandparents; this is that system with better maths.
left to assign = income − sum of every category amount. The goal is exactly zero: over zero means unassigned money, and below zero means you have planned to spend more than you earn.
Take-home income of $3,200 for the month:
| Category | Amount | Category | Amount |
|---|---|---|---|
| Rent | $1,200 | Debt payments | $250 |
| Utilities | $200 | Savings | $450 |
| Groceries | $450 | Fun money | $250 |
| Transport | $180 | Buffer | $130 |
| Insurance | $90 | Total | $3,200 |
$3,200 − $3,200 = $0 left to assign: every dollar has a job.
A method where you give every unit of your income a job before the month begins — bills, groceries, savings, fun — until income minus assignments equals exactly zero. Nothing is left "unbudgeted", which is where money usually leaks. It is the method behind envelope budgeting and apps like Zeroed and YNAB.
No — it means every unit is assigned, and savings is one of the jobs. A zero-based budget with 20% assigned to savings spends nothing extra; it just decides on purpose instead of by accident.
Start with 8–12 broad ones: housing, utilities, groceries, transport, insurance, debt payments, savings, fun money, and a buffer for surprises. Too many categories early on is the most common reason people quit — you can always split later.
You move money from another category to cover it — deliberately. That single act (choosing what to take it from) is the behaviour change that makes zero-based budgeting work where tracking alone fails.
A method where you assign every dollar of income to a category before the month starts, so that income minus planned spending is exactly zero. It does not mean spending everything: savings and debt payments are categories too.
They are close relatives. Zero-based budgeting is the rule of giving every dollar a job; envelope budgeting is the practice of holding each category’s money in its own envelope, physical or digital, and stopping when it is empty. Many apps combine the two.