Effective Discount, Explained
The headline discount % on a promotion often isn't the real discount on merchandise value — especially for BOGO and bundle mechanics.
The formula
Effective discount % = 1 − (Amount paid ÷ Regular value of everything delivered).
Why BOGO's "50% off" is really 50% off two units
A classic Buy One Get One Free deal is often marketed alongside "50% off" language. That is technically correct on a per-unit basis across the 2-unit basket, but it means giving away half your merchandise value on every redeeming order — a much bigger commitment than a 50%-off-one-unit discount.
Bundle discounts often look smaller than they are
A "2 for $50" bundle on a $30 item is only a 16.7% effective discount on merchandise value — smaller than shoppers might assume from bundle marketing, but still a real cost worth calculating precisely.