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Leaked Discount Code Cost Calculator

Reviewed for 2026, updated September 8, 2026.

Estimates how much margin a discount code that escaped onto coupon sites is costing a Shopify store each month and each year, net of the new orders it happens to bring in.

Your numbers

Results update as you type.

Your estimate

Total discount given through this code per month...
Discount going to unintended redemptions per month...
Net margin lost per month...
Net margin lost per year...

Estimates only. Assumptions are listed below, and you can change every input.

A code you built for an email list or an influencer rarely stays private. Once it lands on a coupon aggregator or a browser extension, redemptions climb and the discount goes to shoppers you never meant to reach. The tricky part is that not every leaked redemption is a loss: some of those shoppers were already at checkout and would have paid full price, while others only bought because the code showed up. This calculator separates the two so you can see the real damage instead of the headline discount total.

You enter the code's monthly redemptions, average order value, discount and product margin, plus two judgment calls: what share of redemptions you did not intend, and what share of those people would have bought anyway. The tool charges the full discount against the would-have-bought-anyway group and credits the margin left over on the genuinely incremental orders. The result is a net monthly and annual margin figure. It is only as good as your two share estimates, so try a low and a high value to get a range.

How to use this tool

  1. Pull the code's redemption count and average order value for a recent month from your Shopify discounts report.
  2. Enter your gross margin at full price and the percentage discount the code gives.
  3. Set your best estimate for the unintended share and the would-have-bought-anyway share, then run a cautious and an aggressive scenario to get a range.

What the math assumes

  • Product and fulfillment cost per order do not change when a discount is applied, so every discount dollar comes straight out of gross margin.
  • Unintended redemptions that would have bought anyway cost you the full discount amount on that order.
  • Unintended redemptions that would not have bought otherwise are credited with the margin left after the discount; if the discount is larger than your margin, those orders count as a loss too.
  • The annual figure is the monthly figure times 12 and assumes the leak continues at the same rate all year.
  • The two share inputs are your estimates; the calculator does not see your traffic sources and does not model returns, payment fees or shipping subsidies.

Frequently asked questions

Why can the net margin lost come out negative?

A negative result means the leaked code is bringing in enough genuinely new orders to outweigh the discount handed to shoppers who would have paid full price. That happens when your margin is comfortably above the discount and few of the unintended users were already going to buy.

How do I estimate the share of redemptions I did not intend?

Compare redemptions before and after the code appeared on coupon sites, or check how many redeeming customers belong to the list or campaign the code was made for. Anyone outside that group counts as unintended.

Does this include the discount given to the audience I meant to reach?

No. The discount to your intended audience is treated as the planned cost of the campaign. The calculator isolates the extra cost created by the leak itself.

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