Contribution margin

Contribution margin is net sales less associated variable costs, available to cover fixed costs and then profit. Report currency per unit or period; for the contribution percentage, divide by the same net sales and multiply by 100.[1]

For a web order, include variable payment, platform and shipping costs where they belong in the model. Contribution is not automatically gross profit because cost of sales and variable costs have different scopes. Declare included items, tax basis and period so comparisons remain meaningful.