How to calculate contribution margin, with a worked example

Calculating contribution margin means exposing the economics of a product, order or customer: what is left of the revenue once the variable costs are taken out? That amount covers fixed costs first and contributes to profit after that — which makes it one of the most useful numbers a finance lead has.

This guide covers the definition, the formula with a worked example, the difference between contribution margin 1 and 2 in a tiered analysis, and where you use the metric day to day — from the price floor to the question of which orders actually carry cash flow.

What is contribution margin?

Contribution margin is the difference between revenue and variable costs. It shows how much is left over after the costs that scale with volume are deducted, to “contribute” toward covering fixed costs — hence the name. Only once the sum of all contribution margins exceeds fixed costs does a profit emerge.

The split between the two cost types is what makes the metric work. Variable costs arise with every unit produced or sold — materials, subcontracted work, volume-dependent production costs. Fixed costs arise independently of volume — rent, administrative salaries, insurance, depreciation. Contribution margin deliberately accounts only for variable costs and leaves fixed costs out of the picture at this stage. That is exactly what makes it useful for short-term decisions: it shows the immediate contribution of one unit without fixed costs — which are going to be there regardless — distorting the picture.

Contribution margin: formula and example

The basic formula is simple and applies equally to a full product range or to a single unit:

A worked example with generic illustrative figures shows the mechanics. Take a product that sells for €100 per unit, with variable unit costs of €60, against fixed costs of €120,000 per period:

In this example, the unit contribution margin is €40 — every unit sold contributes €40 toward covering fixed costs and, beyond that, profit. The metric is often expressed as a ratio too: the contribution margin ratio in this example is 40% (€40 of €100), showing what share of revenue is left once variable costs are covered.

The same logic gives you the break-even point: it is reached when the sum of contribution margins exactly covers fixed costs. Break-even volume is fixed costs divided by unit contribution margin — in the example, €120,000 / €40 = 3,000 units. From the 3,001st unit on, the product generates profit. The figures are generic illustrative values used only to demonstrate the mechanics; the logic itself holds generally.

Contribution margin 1 and 2: the tiered analysis

In practice, a single contribution margin figure is often not enough, because fixed costs don’t all behave the same way. Some can be attributed directly to a product line, a location or a customer segment; others are true overhead for the business as a whole. A tiered contribution margin analysis (also called multi-level fixed-cost accounting) handles this by deducting fixed costs in stages.

• Contribution margin 1 (CM1) is revenue minus variable costs — contribution margin in the narrow sense.
• Contribution margin 2 (CM2) comes from subtracting, from CM1, the fixed costs directly attributable to one level — the fixed costs of a product line or a location, for example.

The principle can be extended indefinitely (CM3, CM4), until the remaining company-wide fixed costs are deducted to arrive at the operating result. The insight this delivers: a product can show a positive CM1 and still have a negative CM2 — it covers its variable costs, but not the fixed costs it directly causes. This tiered view surfaces cross-subsidies between products and divisions that a single-stage calculation hides.

What contribution margin analysis is used for

Contribution margin analysis is the standard tool for short-term, decision-oriented costing. Four uses stand out.

• Product profitability and mix: contribution margin per product shows which items carry the business and which generate revenue without much contribution. Where capacity is constrained, contribution margin per unit of the bottleneck resource (per machine-hour, say) decides which product gets priority.
• Customer profitability: calculated at the customer level, it reveals which customers are genuinely profitable once their directly attributable costs are deducted — often a different picture than a simple revenue ranking.
• Order acceptance: whether to take on an extra order comes down, in the short term, to its contribution margin alone. If it’s positive, the order improves the result even if it doesn’t cover full costs — provided spare capacity exists.
• Price floor: the short-term price floor sits at the variable unit cost. Below that, contribution margin turns negative and every unit sold makes the result worse.

The link to liquidity is direct: only orders with a positive contribution margin ultimately carry cash flow. An order that doesn’t cover its variable costs pulls cash out of the business — no matter how full the order book looks. Contribution margin analysis therefore shows not just whether the business is busy, but whether that work translates into available cash — you can run your own figures through the free cash flow calculator. For how that result becomes a reliable period view, see the guide on how to calculate cash flow; for how the cash effect is projected week by week, see cash flow forecasting.

Frequently asked questions

The most important questions on contribution margin and contribution margin analysis are gathered at the end of this page.

Frequently asked questions