How to pick your numbers
Making sensible assumptions
Billboards can't be clicked, so ROI is modeled, not tracked.
These three numbers are your hypothesis about the campaign — here's how to set each one:
👀 Attention rate — of everyone who passes, who actually notices?
A huge lit board at a slow, congested choke point deserves 25–35%.
A mid-size board on a fast, cluttered stretch: 10–15%.
Simple, bold creative earns the higher end. Default 20% is a fair middle.
🛒 Conversion rate — of those who noticed, who eventually buys?
This depends on your product more than the billboard:
everyday low-price products (fast food, load, drinks) 0.5–2%;
considered purchases (appliances, clinics, banks) 0.1–0.5%;
big-ticket (cars, condos) 0.01–0.05% — tiny, but each sale is huge.
A billboard near your actual store converts far better than a general image site.
💵 Average transaction value — your average receipt.
For repeat-purchase products, using first-purchase value is the conservative case;
a new customer's lifetime value is the upside case.
The professional's trick — work backwards: don't predict, gut-check.
The green box under your results tells you how few buyers are needed to break even.
If "1 in 4,000 people who noticed" sounds easily believable for your product, the campaign likely pays for itself.