Contribution Margin Ratio = Contribution Margin ÷ Sales
Contribution Margin = Sales − Variable Costs
Contribution Margin Ratio = (Sales − Variable Costs) ÷ Sales
Contribution Margin Ratio = Contribution Margin per unit ÷ Selling price per unit
Contribution Margin Ratio = 1 − Variable Cost Ratio
Multiply the ratio by 100 to express it as a percentage