Business
Fixed vs Variable Costs
Splitting costs into fixed and variable is the foundation of pricing, break-even analysis, and understanding how a business scales. Here’s the difference.
| Aspect | Fixed costs | Variable costs |
|---|---|---|
| How they behave | Stay the same regardless of output | Rise and fall with output |
| Per-unit as you grow | Fall (spread over more units) | Stay roughly constant per unit |
| Examples | Rent, salaries, insurance, equipment | Raw materials, packaging, shipping, commissions |
| If you produce nothing | Still incurred | Drop toward zero |
| Role in break-even | The total to be covered | Subtracted from price to get contribution |
When to use fixed costs
Fixed costs are the bills you pay no matter how much you sell — they create risk in slow periods but get cheaper per unit as volume grows.
When to use variable costs
Variable costs scale with activity — they’re lower risk when sales are slow but don’t fall per unit as you grow, so they cap how much volume alone can help.
Frequently asked questions
- Can a cost be both fixed and variable?
- Some costs are "mixed" or "semi-variable" — they have a fixed base plus a variable part, like a phone plan with a flat fee plus per-use charges. For analysis, these are often split into their fixed and variable components.
- Why does the split matter for pricing?
- Because each sale must at least cover its own variable cost to contribute anything toward fixed costs. The gap between price and variable cost (the contribution margin) is what pays down fixed costs and eventually becomes profit.
- Do fixed costs stay fixed forever?
- Only within a range. "Fixed" means unchanged by normal output changes, but big jumps in scale (a second factory, more staff) can step fixed costs up. Economists call these "stepped" or "semi-fixed" costs.