What is Fixed vs. Variable Costs?
Which costs move with sales and which do not - the split behind break-even, pricing, and forecasting.
Fixed vs. Variable Costs: definition
Cost behavior determines how profit responds to volume. Fixed costs - rent, salaries, insurance - must be paid whether you sell one unit or a thousand, so they create operating leverage: once covered, additional sales are highly profitable. Variable costs - materials, shipping, hourly labor, processing fees - scale with each unit sold. Some costs are semi-variable (a fixed base plus a usage component).
| Type | Behavior with volume | Examples |
|---|---|---|
| Fixed | Constant in total | Rent, salaried staff, insurance, software licenses |
| Variable | Rises/falls proportionally | Raw materials, shipping, payment processing, commissions |
| Semi-variable | Fixed base + variable part | Utilities, phone plans, some cloud bills |
How Fintra handles it
Fintra lets you tag accounts by cost behavior, so planning models treat fixed and variable costs correctly instead of scaling everything by one growth rate. A volume assumption then flows through variable costs while fixed costs hold, producing a realistic forecast and an accurate break-even.
- Accounts tagged fixed, variable, or semi-variable for driver-based planning
- Volume drivers scale only the variable portion of cost
- Break-even and contribution margin derive from the same tags
Worked example
Frequently asked questions
Are salaries fixed or variable costs?
Salaried pay is generally fixed - it does not change with output in the short run. Hourly wages tied to production, and sales commissions, are variable. Fintra lets you tag each pay type so labor is modeled correctly in the plan.
What is a semi-variable cost?
A cost with both a fixed and a variable component - a phone plan with a base fee plus per-use charges, or utilities with a standing charge plus consumption. For planning, split it into its fixed base and variable rate so it scales accurately.
Why does the fixed/variable split matter?
It drives break-even, pricing, and scenario planning. High fixed costs mean higher risk but greater profit once volume passes break-even; high variable costs mean lower risk but thinner leverage. Knowing the mix tells you how sensitive profit is to volume.
Can a cost change from fixed to variable?
Yes - outsourcing can turn a fixed salaried role into a variable per-project cost, and long-run all costs become variable. Businesses often shift costs toward variable to reduce risk when demand is uncertain.
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