Contribution margin calculator

How to use it

Enter your figures above — the result updates instantly and nothing leaves your browser. Results are illustrative, not a quote or credit decision.

How to interpret the result

A higher contribution margin means each additional sale leaves more behind to cover fixed costs before any profit is made — useful when a limited company is comparing product lines or deciding which orders to prioritise when capacity is tight. A low or thin contribution margin is a signal to look at pricing or variable costs before assuming volume alone will fix profitability.

The figure is most useful compared against itself over time, or against another product or service line, rather than read in isolation. A director looking at management accounts might track whether contribution margin is holding steady, improving, or eroding as input costs or discounting change, since that trend often tells you more than a single snapshot.

Limitations and good practice

This calculator only separates price from variable cost per unit — it does not know your fixed costs, so it cannot tell you the break-even volume or overall profitability on its own. Treat it as one input alongside a proper look at overheads, staffing and other fixed commitments, ideally reviewed with an accountant who knows the full cost base.

Classifying a cost as variable rather than fixed is a judgement call, and getting it wrong in either direction will distort the result. It's worth revisiting the inputs periodically, particularly if supplier terms, staffing structure or production methods change, rather than treating one calculation as valid indefinitely. For a fuller picture, it can help to view this alongside the gross margin and markup calculator or the EBITDA margin calculator.