Contribution Margin Calculator

What is contribution margin?

Contribution margin is the revenue left after subtracting all variable costs from a sale. It shows how much each order contributes toward covering fixed costs and generating profit.

For ecommerce brands, this is the most practical way to evaluate order economics before scaling spend. If contribution margin is weak, growth can increase revenue while reducing profitability. A business can be growing fast and losing money on every order at the same time.

Contribution margin formula

Contribution Margin = Revenue - Variable Costs

Contribution Margin Ratio = (Revenue - Variable Costs) / Revenue

In ecommerce mode, variable costs typically include COGS, shipping and fulfillment, transaction and platform fees, packaging, discounts applied, and expected refund rate.

Contribution margin per unit vs total contribution margin

Contribution margin per unit helps with pricing decisions, product mix analysis, and offer economics. It tells you whether a single order is healthy before you think about volume.

Total contribution margin shows how much money is available across all orders to cover fixed costs and contribute to profit at a given sales volume. Both matter, and neither replaces the other.

Contribution margin vs gross margin

Gross margin typically covers revenue minus cost of goods sold only.

Contribution margin goes further by including all variable costs tied to each sale, such as shipping, fees, discounts, and returns. That makes contribution margin more accurate for CAC planning, break-even analysis, and decisions about whether to scale a channel or product line.

Ecommerce examples

Example 1: Healthy-margin product

• Selling price: $150
• Variable costs (COGS + shipping + fees + packaging): $60
• Contribution margin per unit: $90
• Contribution margin ratio: 60%
• Max allowable CAC before fixed overhead: $90

With $90 of contribution margin per order, this product can absorb meaningful paid acquisition cost and still contribute to fixed costs. Most channels are viable to test.

Example 2: Thin-margin product

• Selling price: $50
• Variable costs: $41
• Contribution margin per unit: $9
• Contribution margin ratio: 18%
• Max allowable CAC before fixed overhead: $9

At $9 max CAC, nearly every paid channel becomes unprofitable immediately. Scaling volume here accelerates losses rather than improving them. The unit economics problem has to be solved before any growth lever makes sense.

What is a good contribution margin?

There is no single universal benchmark. A contribution margin ratio above 40% is generally considered healthy for ecommerce. Ratios below 20% make it very difficult to run profitable paid acquisition because there is too little room to absorb CAC before eroding profitability.

The right target depends on your operating cost structure, average order value, and how often customers repeat. A brand with high repeat purchase rates may survive on thinner first-order margins. A brand relying on paid acquisition for almost every order cannot.

Contribution margin and CAC

Contribution margin per order sets the ceiling for your maximum allowable customer acquisition cost before fixed overhead. If CAC exceeds contribution margin per order, every new customer acquired increases losses at the variable-cost level regardless of revenue.

This is where the relationship between margin and channel spend becomes critical. A 4x ROAS on a product with 18% contribution margin can still be unprofitable. Contribution margin shows you whether the underlying economics support the acquisition strategy before you look at any campaign metric.

Why manual contribution margin calculators are limited

A static calculator is useful for planning and scenario modeling. But contribution margin shifts every time variable costs move, and in ecommerce those costs move constantly. Supplier prices change. Shipping rates adjust. Return rates spike after a promotion. A discount campaign quietly compresses margin across your entire catalog.

By the time you have updated the spreadsheet, the numbers are already wrong.

Teams that scale paid channels need live visibility into contribution margin by product, order, and channel, updated as Shopify and ad platform data changes. Daymark connects your store and ad accounts so you can monitor per-order profitability continuously, without rebuilding the spreadsheet after every cost change.