Plain definition
Contribution margin ratio equals contribution margin ÷ sales revenue, usually expressed as a percentage. It shows how much of each sales currency unit contributes to fixed costs and profit on the stated cost basis.
Illustrative example
Monetary examples use Saudi riyals (SAR). The same principles apply in other currencies.
A service generates revenue and variable cost, giving contribution and a 40% ratio. A forecast of additional sales would add contribution only if the same price, mix, and variable-cost rate hold.
Why it matters
The ratio is useful for scenario planning, but it can mislead when discounts, commissions, product mix, or capacity change.
Practical consequence
Calculate it by product or channel where economics differ, label the cost basis, and revise the forecast when a commercial term changes rather than carrying one historic ratio forward.
Try your own numbers
See the unit volume needed to cover fixed costs, and the planned profit at a chosen volume.
Break-even