Understanding your margins: a practical guide for independent retailers
Finance & reporting · 3 June 2026 · 7 min read
Margin vs markup — get this right first
These two get confused constantly, and mixing them up leads to real pricing mistakes.
Markup is how much you add to the cost price. If something costs you £1 and you sell it for £1.30, your markup is 30%.
Margin is what percentage of the selling price is profit. That same product — costs £1, sells for £1.30 — has a margin of 23.1% (30p profit divided by 130p selling price).
When suppliers quote you "30% margin", they usually mean 30% markup. When a retailer talks about their margin, they mean the percentage of the sell price that's profit. Always clarify which is meant.
For most convenience store categories, healthy gross margins look like this:
- Soft drinks / energy: 25–35%
- Confectionery: 28–38%
- Tobacco: 6–12% (low margin, high volume)
- Alcohol: 20–30%
- Dairy: 15–25%
- Hot food / bakery: 40–60% (when waste is controlled)
Where margin surprises usually come from
Shrinkage you haven't accounted for
Your margin on paper is calculated from your buy price and sell price. Your actual realised margin factors in waste, theft, and damaged stock. A product with a 30% on-paper margin might actually be returning 20% once you subtract the losses.
This is why tracking waste per product matters. It's the difference between a product that looks profitable and one that actually is.
Promotional pricing
Running a BOGOF or a "3 for £2" deal on a product with 25% margin can quickly push you into negative territory. Do the maths before agreeing to supplier promotions — many of them benefit the supplier more than the retailer.
A useful rule of thumb: if you're reducing the sell price by more than 15%, check that you'll still clear your cost price on the promotional volume.
VAT category errors
Some products get misclassified between standard rate (20%), reduced rate (5%), and zero rate (0%). If you're treating a zero-rated product as standard-rated, you're handing 20% to HMRC every time it sells.
Common ones to double-check: children's clothing, most food for human consumption (zero-rated), hot food (standard-rated), cold prepared food to take away (often zero-rated but varies).
Acting on what your margin data tells you
Sort your products by gross margin. Look at the bottom 15% — not to automatically cut them, but to understand why they're there. Some low-margin products (tobacco, lottery) are traffic drivers that pull in footfall for higher-margin sales. Others are just priced wrong or receiving too much waste.
Build a habit of reviewing the bottom quartile of your margin report every month. A small tweak to 10–15 products is usually enough to maintain where you want to be overall.
The one number to track every week
If you take nothing else from this: track your overall gross margin percentage week on week.
It doesn't need to be exact. A rough sense of "we're at around 26% this week vs 27% last week" tells you a lot — especially if you see it drifting in one direction. That's your cue to look at what's changed: a new line, a supplier price increase, a waste spike, or a pricing error.
Margins are the score. Everything else is the game.