How to use these calculators
A promotion can grow top-line sales but reduce total contribution. Compare regular and promotional unit economics, then separately estimate the shipping subsidy cost for a representative order. Consider incremental fulfillment and campaign spending before declaring a promotion profitable.
A worked scenario
Promotion contribution lift: $100; example subsidized order contribution: $8.
A positive promotion lift does not automatically cover additional campaign expenses or inventory handling.
How to plan this decision
- Compare contribution not revenue
Run both total-profit scenarios on the same time frame.
- Keep costs separate
Avoid double counting shipping subsidies as a fulfillment charge.
- Test order mix
Account for customers who would have purchased without the discount.
Read the detailed worked guide →
Start with the formula
Learn why margin and markup produce different percentages and how to use each one when setting prices.
Read Margin vs. Markup: the Difference That Changes Your Pricing →