Contribution Margin Calculator
By Herzel MishelFounder, AgentisLast reviewed
Contribution margin is the dollars left over from each sale after you subtract every variable cost, and the true amount each unit contributes toward paying fixed costs and then generating profit. It is the single most honest number in ecommerce unit economics, and it is also the number most founders quote incorrectly because they confuse it with gross margin. This calculator takes your price, variable cost per unit, fixed costs, and units sold, and returns your contribution margin per unit, contribution margin percentage, total contribution, and the break-even units implied by your fixed-cost base. It is designed for mid-market Shopify Plus operators who want to stop arguing with finance about whether a SKU is actually profitable and start making pricing and promo decisions against a defensible number.
Inputs
Average realized selling price after standard promo activity.
COGS plus pick-pack, outbound freight, and payment fees.
Salaries, rent, software: anything that does not scale with order volume.
Total units moved in the period you are modeling.
Results
Contribution Margin per Unit
$52.00
Contribution Margin %
57.78%
Total Contribution
$130,000
Break-Even Units
1,154
What the Result Means
Healthy mid-market DTC contribution margins generally land between 35 and 55 percent. Beauty and supplements brands with strong pricing power hit 55 to 65 percent. Apparel typically runs 30 to 45 percent. Electronics and commodity categories often fall below 25 percent, which is where unit economics start getting fragile: any freight rate bump or CAC increase pushes the product into negative territory. The test is not just whether contribution margin is positive; it is whether total contribution is large enough to cover fixed costs with margin to spare. A brand doing 2,500 units at a 52 dollar contribution margin generates 130,000 in contribution; if fixed costs are 60,000, you have 70,000 of operating leverage. If fixed costs are 125,000, you are barely breaking even and any volume dip puts you underwater. Contribution margin is also the right number to use when deciding whether to fulfill low-ticket or heavily discounted orders: if contribution is negative, more volume makes the problem worse, not better.
How It's Calculated
Contribution margin per unit is calculated as Unit Price minus Variable Cost per Unit. Variable cost should include every dollar that scales with each additional order: product COGS, inbound freight amortized per unit, outbound fulfillment (pick, pack, ship), packaging, payment processing, and return handling reserves. It should NOT include fixed overhead like salaries, rent, or software subscriptions; those live in fixed costs. Contribution margin percentage is Contribution Margin per Unit divided by Unit Price, expressed as a percentage. Total contribution is Contribution Margin per Unit multiplied by Units Sold, and represents the pool of dollars available to cover fixed costs and then drop to profit. Break-even units is Fixed Costs divided by Contribution Margin per Unit: the number of units you have to sell before total contribution equals fixed costs. This model assumes a single SKU or constant mix. If you run a wide catalog with very different margin profiles per SKU, calculate contribution margin at the SKU level and weight by mix rather than running a blended average, which will hide your worst performers.
The Gap This Calculator Reveals
Contribution margin calculated at the period level is a planning number. Contribution margin calculated at the order level is a control number, and that is where mid-market brands lose money they did not budget for. A promo code plus a remote zip plus a restocked return can turn a 52 dollar contribution margin into a negative number on a specific order, while the blended number still looks fine. Agentis recomputes contribution margin per order within 60 seconds of each order against live COGS, freight, and the actual discount stack, and flags or holds orders that fall below your floor before they ship. The calculator gives you the target; Agentis checks that every individual order clears it.
Sources
Frequently Asked Questions
What is the difference between contribution margin and gross margin?
Gross margin deducts only COGS from revenue. Contribution margin deducts COGS plus every other variable cost: fulfillment, payment fees, packaging, and outbound freight. Variable cost also includes inbound freight amortized per unit and a reserve for return handling, since both scale with each order shipped. It should not include salaries, rent, or software subscriptions; those are fixed costs and belong in a separate input. Contribution margin is always lower than gross margin and is the more honest number for unit economics decisions. The distinction matters because contribution margin is the pool of dollars available to cover fixed costs and then drop to profit; gross margin overstates that pool. Founders often quote gross margin when they mean contribution margin, which is why finance and operations disagree about SKU profitability. Enter your realized price and full variable cost per unit here to see how far your contribution margin sits below the gross margin you usually quote.
Is a 40% contribution margin good?
For most mid-market DTC categories, 40 percent is solid. Healthy mid-market DTC contribution margins generally land between 35 and 55 percent, so 40 percent sits inside the normal range. Beauty and supplements should push higher (50 to 65 percent); apparel 30 to 45 percent is normal; commodity electronics may only hit 15 to 25 percent. Below roughly 25 percent, unit economics become fragile: a freight rate bump or a CAC increase can push the product into negative territory. Evaluate it against your category benchmark, not an absolute. The percentage alone is not the whole test; total contribution must also cover fixed costs with room to spare. A brand selling 2,500 units at a 52 dollar contribution margin generates 130,000 in contribution, which against 60,000 of fixed costs leaves 70,000 of operating leverage but against 125,000 barely breaks even. Compare both outputs here against your own fixed costs.
Should marketing be included in variable cost?
Performance marketing that scales with each acquired customer (Meta, Google) should be modeled as a variable cost per unit when you are assessing true unit economics. Brand marketing overhead sits in fixed costs. The test is whether the cost moves with each additional order: paid acquisition spend does, while a brand team's salary or creative software does not. Many brands conveniently leave CAC out of contribution margin to make the number look better; do not fall into that trap. Leaving CAC out inflates contribution margin per unit, which in turn understates break-even units, since break-even is fixed costs divided by contribution margin per unit. The same logic applies to any decision about fulfilling heavily discounted or low-ticket orders; if the contribution after acquisition cost is negative, more volume makes the problem worse. Run this calculator with and without acquisition cost in the variable cost input and compare the break-even units.
How is contribution margin used for break-even?
Break-even units equals fixed costs divided by contribution margin per unit. Contribution margin per unit is unit price minus variable cost per unit, where variable cost covers COGS, inbound freight amortized per unit, pick-pack, outbound freight, packaging, payment processing, and return handling reserves. It tells you exactly how many units must sell before contribution covers fixed costs and the next unit starts dropping into profit. Total contribution, which is contribution margin per unit multiplied by units sold, is the pool that has to exceed fixed costs before any profit exists. Because the formula divides by contribution margin, a small drop in that figure raises break-even units sharply. This model assumes a single SKU or constant mix; for a wide catalog, run it per SKU so a blended average does not hide weak performers. Compare the break-even units output here with the units sold you entered to see how much volume headroom you actually have.
More margin Calculators
Related Calculators
Calculator
Profit Margin Calculator
Free net margin calculator for ecommerce. Enter revenue, COGS, and expenses to get net profit margin percentage and gross margin, with 2026 benchmarks.
Calculator
Break-Even Calculator
Free break-even calculator. Calculate break-even units and break-even revenue from fixed costs, unit price, and variable cost, with contribution margin analysis.
Calculator
True Product Cost Calculator
Calculate your all-in true product cost: landed cost, fulfillment, returns, and payment fees. See how much your naive COGS margin is overstating reality.
Related Concepts
Margin Analysis
Contribution Margin
The revenue remaining after deducting all variable costs associated with fulfilling an order, including COGS, shipping, payment processing fees, and pick-and-pack labor.
Margin Analysis
Gross Margin
The percentage of revenue remaining after subtracting the cost of goods sold, a foundational profitability metric that excludes operating expenses, taxes, and interest.
Margin Analysis
Margin Leakage
The gradual, often undetected loss of profit across many orders, driven by small per-order cost overruns that compound into significant revenue erosion over time. Also called revenue leakage, a term more common in marketplace-seller (Amazon/Walmart) contexts for the same underlying pattern.
Related Benchmarks
Contribution Margin %
Contribution Margin Benchmarks for Ecommerce
Contribution margin benchmarks that account for COGS, shipping, fulfillment, returns, and payment processing: the true measure of ecommerce order profitability.
Gross Margin %
Ecommerce Gross Margin by Category 2026: 15-80% Benchmarks
Real 2026 benchmarks: beauty 60-80%, supplements 55-70%, fashion 45-65%, electronics 15-30%. See where your category sits and why 20% of brands miss the floor.
Free Audit, No Commitment
Stop Just Calculating Margin. Enforce It.
Agentis checks every Shopify Plus order's true net margin within 60 seconds and flags or holds the ones below your profit floor before they ship. Start a free 7-day audit and see your order-level profitability.