Milliseconds make millions: what page speed does to revenue
A tenth of a second sounds like nothing. Across retail, travel and luxury sites it moved conversions by 8–10%. Here is what the research found and what to do about it.
Most speed conversations end at “faster is better” and never get to “how much better, and is it worth paying for.” That’s a problem, because the answer is one of the clearest in digital marketing.
In 2020 Deloitte Digital, working with Google, analyzed 37 retail, travel, luxury and lead-generation brands across Europe and the US. Instead of lab tests, they looked at real traffic over four weeks and asked a simple question: when the same site gets a tenth of a second faster on mobile, what happens to the numbers that matter?
What a tenth of a second bought
A 0.1 second improvement in mobile site speed moved conversion rates by 8.4% for retail sites and 10.1% for travel sites. Retail shoppers also spent more per order, with average order value up 9.2%. On luxury sites, where purchases rarely happen on the first visit, the lift showed up as 8.6% more pages viewed per session. Lead-generation sites saw more form completions and more pages viewed.
The thing to notice is the size of the input. Not a full second. Not a redesign. A tenth of a second, the kind of improvement you get from compressing images properly or removing a tracking script nobody uses.
Why it works
Speed is felt before anything else on a page is read. A slow page communicates this might not work before the visitor has seen a product or a price. Fast pages don’t convert because they’re fast; they convert because nothing has yet given the visitor a reason to leave.
The effect is also strongest exactly where you’d want it: deeper in the funnel, on product pages and checkout steps, where the visitor has already shown intent and the only thing that can lose the sale is friction.
What to do with this
- Measure real users, not lab scores. Use field data (Chrome User Experience Report, or your analytics vendor’s real-user monitoring) and look at the 75th percentile, not the average.
- Fix the page that makes money. Speed budgets for the homepage are nice. Speed budgets for the product page and checkout are where the revenue is.
- Audit your third-party scripts quarterly. The typical mid-size site carries 20–40 of them. Most were added for a campaign that ended.
- Serve images at the size they’re displayed. This single change is still the most common and the cheapest win we find.
- Put a number on it. Take your monthly revenue, multiply by 8%, and that’s roughly what a tenth of a second is worth. Most speed work pays for itself in weeks.
We run a performance baseline on every project before design starts. If you’d like one for your site, get in touch.
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