---
title: "Variable cost: definition, formula and example"
description: "A cost that exists because an order does: product, pick, box, label, card fee. It is what contribution margin subtracts, and what an offer changes."
url: https://offersuite.io/glossary/variable-cost
updated: 2026-10-13
---

# Variable cost

A cost that exists because an order does: product, pick, box, label, card fee. It is what contribution margin subtracts, and what an offer changes.

## In plain words

A variable cost is one you pay because a particular order happened. No order, no cost. The product in the box, the warehouse's fee to pick it, the box, the label and the card fee are all variable.

Fixed costs are the rest: rent, salaries, software, the photo shoot. They are owed whether you ship one order this month or ten thousand. An offer decision should look only at variable costs, because those are the only ones the offer can move.

## Formula

- Variable cost of an order = Σ of every cost that order caused
- Contribution margin = revenue − variable cost

## Worked example

The $40.00 bag's order has $24.64 of variable cost. Every cent of it is there because the order was placed.

Three bags in one order cost $53.94, well under three times as much. Variable does not mean proportional: the product cost tripled to $36.00, while the label stayed at $7.50.

### The example order

A $40.00 bag of coffee, shipped free, every cost counted

Revenue $40.00 to contribution margin $15.36 (38.4%)

Revenue

$40.00

Cost of goods

−$12.00

Pick and pack

−$1.18

Packaging

−$0.50

Shipping label

−$7.50

Card fee per order

−$0.30

Refunds

−$2.00

Card processing

−$1.16

Contribution margin

$15.36

2 declared kinds cost nothing on this option

Computed by the margin engine in Offer Suite's own code, in whole cents, from a $40.00 bag of coffee with a $12.00 unit cost.

## Variable does not mean it scales with units

Some variable costs are charged per unit, some per order, some per parcel and some as a share of revenue. All of them are variable, because none exists without the order. Treating them all as per-unit is the usual way a bundle gets mispriced.

## Using it

List every cost an order triggers and write next to each how it is charged: per unit, per order, per parcel or as a percentage. Leave advertising out of the order's variable cost and treat it as the cost of winning the customer. It is set by the campaign, not by the offer, and mixing the two hides both.

## Related

- [Glossary **Glossary of offer economics** The terms behind offer profit, defined plainly with their formulas and a worked number: contribution margin, profit per visitor, break-even lift and more.](https://offersuite.io/glossary)
- [Calculator **Bundle pricing calculator: shipping, subscriptions** Price a bundle against a single unit, one-time and subscribed, with the shipping and pick costs it saves, and the conversion it can lose and still earn as much.](https://offersuite.io/calculators/bundle-pricing)
- [Calculator **Gift with purchase profit calculator** What a free gift costs per order, after its unit cost, its extra pick and its handling, and how much conversion it has to add to pay for itself.](https://offersuite.io/calculators/gift-with-purchase-profit)
- [Glossary **Contribution margin: definition and formula** What an order keeps after every cost that grows with it: product cost, fulfilment, shipping, card fees and refunds. The number an offer should be judged on.](https://offersuite.io/glossary/contribution-margin)
- [Glossary **Cost grain: definition, formula and example** The level a cost is charged at: per unit, per parcel, per order or as a share of revenue. Counting a cost at the wrong grain misprices every bundle.](https://offersuite.io/glossary/cost-grain)
- [Glossary **Fulfilment cost: definition, formula and example** What it costs to get an order out: pick and pack, extra picks, the box and the label. Charged per order or parcel, which is why bundles and gifts change it.](https://offersuite.io/glossary/fulfilment-cost)