Discount Codes and What They Do to Your Margin
Discounts are the easiest lever to pull and the hardest to un-pull. Before running the next one, do the arithmetic on what it actually costs and what behavior it teaches.
The arithmetic
On a $100 item with a 40% gross margin, you make $40. A 20% discount takes $20 off the price and $20 off the profit: half your margin, for a fifth off the sticker. To break even on profit you would need to sell twice as many units. Promotions are worth running when they clear inventory, acquire customers with real repeat value, or fill genuinely dead periods. They are not worth running because it is a Tuesday in September.
The habit problem
Customers learn quickly. Run a sale every month and your regular price becomes the price nobody pays; shoppers wait, and your average order value drifts down permanently. The strongest signal of this is a rising share of orders using a code. Track that percentage; when it climbs past a third, discounting has become your pricing.
Better structures than a blanket percentage
- Threshold offers: free shipping or a discount over a spend level, which raises order value instead of lowering it.
- Bundles, which move slow inventory alongside popular items and are harder to compare against competitors.
- First-order only, tied to an email signup, so the cost buys you a contactable customer.
- Time-boxed and specific, with a real end date, on a defined category.
- Loyalty or repeat-purchase rewards, which reward the behavior you want rather than the moment of hesitation.
Protect against leakage
Codes end up on coupon aggregator sites within hours, where they are found by customers who were going to buy anyway. Use unique single-use codes for outreach, set expiry dates, exclude already-discounted items, and set usage limits. Also check whether your checkout advertises a code field prominently; a visible empty box sends people to a search engine mid-purchase, and some of them do not come back.
Measure the right thing
Not revenue during the promotion. Gross profit during and for the month after, compared with a normal period. Promotions that pull forward demand look successful in week one and neutral in the quarter.
