Contribution margin is a business’ sales revenue less its variable costs. The resulting contribution dollars can be used to cover fixed costs (such as rent), and once those are covered, any excess is considered earnings. Contribution margin (presented as a % or in absolute dollars) can be presented as the total amount, amount for each product line, amount per unit product, or as a ratio or percentage of net sales. [1]
[1] Corporate Finance Institute. Retrieved May 21, 2021, from https://corporatefinanceinstitute.com/resources/knowledge/accounting/contribution-margin-overview/
[2] Retrieved May 21, 2021, from https://www.investopedia.com/terms/c/contributionmargin.asp