Initial Markup (IMU) is the percentage added to cost of goods sold to set a product's first retail price before any markdown, discount, or promotion ever touches it. The formal version accounts for planned reductions: IMU% equals maintained markup plus reductions, divided by net sales plus reductions. Everything else in retail pricing math is a variation on protecting or eroding that one number.
How the formulas actually work
Retail pricing math runs on a handful of numbers that get used interchangeably in casual conversation and mean genuinely different things on a P&L. Cost of Goods Sold (COGS) is the landed cost of the product, what it costs to acquire, ship, and store before it ever reaches a customer. Initial Markup is what you add to that cost to set the first retail price: at its simplest, retail selling price minus COGS. The fuller planning formula, IMU% = (Maintained Markup% + Reductions%) / (Net Sales% + Reductions%), exists because merchandise planners set IMU high enough to absorb reductions they already know are coming.
Maintained Markup Percentage is the number you actually keep: (Net Sales - COGS) / Net Sales. It is IMU after reality happens to it. Gross Margin is the same gap expressed at the P&L level: (Gross Sales - Discounts - Returns) / Gross Sales. Reductions is the umbrella term for everything that separates IMU from maintained markup, including markdowns, employee discounts, customer discounts, and shrink, which is the dollar value of goods lost, stolen, or damaged before they ever sell.
Two more formulas matter once you are past pricing a single unit and into deciding whether a promotion is worth running. Contribution Margin is gross margin minus direct variable costs, what is left to cover fixed costs and profit. Break-even point is fixed costs divided by unit contribution margin. The percent break-even sales change tells you how much volume a price change needs to generate to pay for itself: (-% price change / (% contribution margin + % price change)) x 100.
Why it matters now
Most Shopify profitability dashboards report a single "profit" number calculated as price minus COGS, which is IMU dressed up as if it were the final answer. It is not. Reductions have not happened yet in that number: no markdowns, no shrink, no financing fees, no returns. An operator making decisions off that dashboard is planning against a price that was never realistic once real-world selling started.
The gap between what the dashboard shows and what actually lands as maintained markup is exactly the gap this framework exists to name. IMU is not a profitability guarantee. It is the starting line.
How IMU differs from maintained markup and gross margin
IMU is planned: the number a merchandiser sets before a single unit sells, built to absorb reductions that have not happened yet. Maintained markup is realized: the actual percentage kept after markdowns, discounts, and shrink have done their damage over a selling period. Gross margin is effectively the same realized concept, but expressed at the P&L level against gross sales rather than at the SKU level against net sales.
None of the three is wrong. They answer different questions asked at different points in the selling cycle, and pricing tools that only report one of them are giving you a partial answer dressed up as a complete one.
How to apply IMU pricing to your store
- Calculate your target IMU from cost and your desired margin before you plan any promotions against the product.
- Track actual reductions, including markdowns, discounts, and shrink, as they happen so you can calculate real maintained markup rather than assuming IMU held.
- Feed both numbers into an allowance-based pricing tool so your starting price already accounts for planned reductions, instead of discovering the gap at season-end.
The formula glossary
| Term | Formula | What it tells you |
|---|---|---|
| Cost of Goods Sold (COGS) | Landed cost of the product | The floor every other number is measured against |
| Initial Markup (IMU) | Retail Price - COGS, or (MMU% + Reductions%) / (Net Sales% + Reductions%) | The price you set before anything happens to it |
| Maintained Markup % | (Net Sales - COGS) / Net Sales | What you actually kept after reductions |
| Gross Margin | (Gross Sales - Discounts - Returns) / Gross Sales | The P&L-level version of maintained markup |
| Reductions | Markdowns + discounts + shrink | The gap between IMU and maintained markup |
| Contribution Margin | Gross Margin - direct variable costs | What is left to cover fixed costs and profit |
| Break-Even Point | Fixed costs / unit contribution margin | Volume needed to cover fixed costs |
Where Price Builder fits
The textbook version of this math lumps every reduction into one plug number. Price Builder itemizes it: selling price is calculated as COGS plus profit markup plus shrink plus shipping plus discounts plus financing plus a market adjustment. That is an IMU price built from named allowances instead of a single guess.
The result is the same concept the textbook describes, but every component of the gap between IMU and maintained markup is visible and adjustable before a single unit sells, not reconstructed after the season closes.
FAQ
What is IMU pricing in retail?
IMU, or Initial Markup, is the percentage added to cost of goods sold to set a product's first retail price. It is calculated before any markdown, discount, or promotion, which makes it the starting point every other pricing metric is measured against.
What is the difference between IMU and maintained markup?
IMU is planned and set before selling begins. Maintained markup is realized, meaning it is the actual percentage kept after reductions like markdowns, discounts, and shrink have happened over the selling period. The gap between the two is the cost of running the business in the real world.
What counts as a reduction in retail pricing math?
Reductions include markdowns, employee and customer discounts, and shrink. Together they are the plug that reconciles planned IMU down to realized maintained markup.
How is gross margin different from maintained markup?
They are conceptually the same gap, viewed at different levels. Maintained markup is typically calculated per SKU or category against net sales. Gross margin is the P&L-level version, calculated against gross sales after discounts and returns.
What is the difference between gross margin and contribution margin?
Gross margin measures what is left after cost of goods sold. Contribution margin goes one step further, subtracting direct variable costs from gross margin to show what is actually available to cover fixed costs and generate profit.
How does shrink affect my pricing if it does not happen to every product?
Shrink is typically budgeted as a category-level or storewide percentage rather than tracked per unit, because you do not know in advance which units will be lost, stolen, or damaged. Building an expected shrink allowance into IMU means the cost is priced in across the category instead of absorbed as a surprise.