Build a zero-based budget where every dollar is assigned a purpose with envelope categories and variance tracking.
Zero-based budgeting means every dollar of take-home income gets an assignment before the month starts, with nothing left in an unlabeled leftover bucket. You enter your income and envelope categories (rent, groceries, savings, and so on), assign an amount to each, and the tool totals them to show whether your assignments exactly match your income. It also tracks variance per envelope, comparing what you planned against what you actually spent, so an overrun shows up immediately rather than surfacing at month end. The mistake most people make: building the budget from gross pay, then wondering why it never balances. Your salary minus taxes is not your salary.
A concrete input and expected output from the current implementation.
Input
Net monthly income: 4800 Rent 1600, Groceries 650, Utilities 280, Transport 340, Insurance 210, Savings 1100, Fun 300, Emergency fund 320
Expected output
Assigned: $4,800 across 8 envelopes. Income: $4,800. Unassigned: $0. Budget closes at zero. Variance per envelope: not shown until actual spending is logged.
The amounts sum to exactly $4,800, so the tool reports zero unassigned. Assigned equals income, which is the defining condition of a zero-based budget; the $320 surplus was deliberately placed in an emergency fund rather than left as an unlabeled leftover.
You enter take-home income for the period, create envelope categories, and give each one an amount. The tool sums all assignments and compares the total with income. The budget only closes when assigned equals income; any difference appears as unassigned surplus or an over-assigned deficit, which you resolve by adjusting categories such as savings, debt payoff, or emergency fund until the total matches.
Planned amounts are recorded per envelope. When you log actual spending for the month, each category gets a variance, planned minus actual. A positive variance means you spent less than planned and the unspent amount can roll into next month's budget; a negative one means you overspent, and the overage must be covered by pulling from another envelope or from additional income.
The tool compares total assigned against the income you entered. If you used gross pay instead of take-home, or left an envelope unfunded, the totals cannot match. Re-enter net income for the period, make sure every category you plan to spend from has an amount, and check the unassigned figure again.
By definition there should be none: a zero-based budget closes when total assigned equals income. If your categories come to less than income, put the difference into an envelope you create for the purpose, typically savings, emergency fund, or extra debt payment. Assigning it to 'miscellaneous' defeats the method, because that is exactly the unplanned bucket it removes.
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