Play · budgeting & margin

Budget Sandbox

Updated 2026-07-25 · Concept: zero-based budgeting, margin, emergency fund

A budget that only works in a perfect month is a wish. Here you build a plan where every dollar has a job (give, save, owe, live), then press Run the month and let life happen to it. Survive enough months and your storehouse grows. Nothing you enter is stored or sent.

Monthly take-home ($)

Line	Job	$ / month
Unassigned	must be $0: every dollar gets a job	n/a

Storehouse (emergency fund)

0.0 months of expenses

Months survived

There is treasure to be desired and oil in the dwelling of the wise; but a foolish man spendeth it up.

Proverbs 21:20

KJV. The wise keep a store; the fool consumes everything that comes in. Margin is not hoarding; it is the room that lets you absorb trouble and stay generous. (On hoarding, see Luke 12 and the Barn Builder.)

This tool needs JavaScript. The paper version works just as well: write next month's take-home at the top of a page; assign every dollar a job in this order (give, save, owe, live) until the unassigned amount is exactly zero. At month's end, compare the plan to what happened. The full method: Your first budget.