What variables are – Budgeting

What variables areBudgetingYou know why a named value beats a typed number, and what the three kinds of variable are.A variable is a **named value** the whole budget can refer to. Instead of typing 45 into thirty per-diem rows, you define `PerDiem` once and reference it thirty times.Why it matters more than it soundsThe saving is not the typing. It is that a budget built from variables can be **re-planned**, and one built from typed numbers can only be re-typed.When the shoot gains a week, a budget whose quantities reference the shoot's duration re-costs itself. A budget with 23 typed into forty rows requires someone to find all forty — and the failure mode is not that it takes an hour, it is that they find thirty-eight.The three kinds**Your own.** Values you define and organise into groups — rates, counts, assumptions. These are the ones you create.**Work phases.** Every phase on the timeline automatically becomes two variables — its workdays and its total days. You do not create them; they exist because the phase does — see [use phase durations in formulas](/kb/article/use-phase-durations-in-formulas).**Subtotals.** Every subtotal you insert becomes a variable, so a later calculation can be based on it. Plus the system ones — net production costs, grand total, DFFF — which have a live value and no formula, because the budget itself computes them.What a variable holdsA **value**, or a **formula** that produces one. `CrewSize` might be 24; `TotalCrewDays` might be `CrewSize * Shooting_workdays`. A variable built from other variables is normal and is how a small set of assumptions drives a large budget.Where they can be usedAnywhere a formula is accepted: quantity, price and factor on an account, a supplement multiplier, an extra cost's quantity, a fringe timebase, a markup base — see [use variables in a budget](/kb/article/use-variables-in-a-budget).The caveatVariables make a budget responsive and less readable. Someone opening it sees `CrewSize * Shooting_workdays` where they expected 480. Two habits fix that: name variables for what they mean, and use the **Comment** column — it exists to hold the sentence the name cannot.Markdown