A slow store loses sales you never see
A fraction of a second changes how much people buy on a phone. Most of what slows a Shopify store was added after launch, and most of it can come out.
September 25, 2026
What the research shows.
When mobile sites got one tenth of a second faster, retail shoppers bought more. That comes from a study Google commissioned from Deloitte, which tracked 37 brands and 30 million visits over four weeks; the retail figures come from 15 of those brands. Google wants a faster web, so it had a reason to fund this, but the numbers come from real stores, not a survey.
- +8.4%More retail shoppers completed a purchase
- +9.2%More spent per order
Nobody writes to tell you your store felt slow. They just leave, and it looks like a quiet week.
What's really going on.
Most stores are fast on launch day. What slows them down is everything added afterwards. Every app that shows a pop-up, a review widget, a chat bubble or a tracking pixel adds its own code to every page, and your customer's phone has to load all of it before it can show your products.
Apps also leave things behind. Older apps wrote code straight into the theme, and removing the app doesn't always remove the code. So a store can go on loading code for an app it removed long ago.
The first screen matters most. A slideshow or an autoplaying video at the top of the home page is often the heaviest thing on the site, and it's the first thing a phone has to load.
What you can do this week.
Test your home page and your best-selling product page at pagespeed.web.dev, and read the Mobile tab. If your store has enough visitors, the top section shows how fast it is for your real customers.
Go through your installed apps and remove any you don't actively use.
Look at your home page on your phone. If the first thing you see is a slideshow or a video, try a single strong image instead and compare.
Before adding a new app, ask whether it needs to be on every page, or only on one.
What we take off your plate.
The list above catches the obvious. The rest needs someone who reads the code: finding the scripts that shouldn't be there, clearing out what old apps left behind, and loading the extras only after your products are on screen.
We measure the real page on a real phone before and after every change, so you know it worked, and we keep checking as new apps go in. You don't need to know what any of it means, only that your store stays fast.
Talk to us about your storeSources
- Deloitte for Google, Milliseconds Make Millions
37 brands and 30 million sessions over four weeks; 15 retail brands and 20.5 million sessions behind the retail figures. Commissioned by Google, prepared by Deloitte Ireland, data collected by Fifty-Five. Read at the source on 2026-09-25.