Discount codes that do not quietly destroy your margin

A discount code is easy to create and hard to evaluate. The uncomfortable question is not how many were redeemed — it is how many of those people would have bought anyway. A code redeemed by someone already on your event page did not create a sale. It gave away margin on one you already had.

The controls that matter

• Percentage or fixed amount, with an optional maximum discount so 20% off does not become £40 off a table
• Restricted to specific tiers — discount general admission without touching VIP
• Total redemption limit, and a separate per-customer limit that stops one person clearing the allocation
• Start and expiry times, because an unexpiring code circulates forever
• Minimum spend, which is how a code raises basket size instead of lowering it

Reporting that answers the real question

Each code reports redemptions, revenue after discount, and the discount given away as a share of gross. Read alongside your sales curve, a code that spikes redemptions without moving the curve is subsidising existing demand — and the right response is to stop running it, not to run it harder.

Where codes genuinely work

Codes work when they are attached to a channel you can otherwise not measure: a specific radio read, a partner's newsletter, a flyer at a different venue. The code is the measurement instrument. Used that way it earns its margin back in information even when it loses it in revenue.