Gross Margin Contribution
Gross Margin Contribution

Definition
Gross margin contribution is the additional profit that a sale generates by subtracting all variable costs. For many online sales there is often little cost to selling additional units and so small improvements in the conversion rate can result in a large uplift in profit.
Resources:
Conversion marketing – Glossary of Conversion Marketing.
Over 300 tools reviewed – Digital Marketing Toolbox.
A/B testing software – Which A/B testing tools should you choose?