Shopify speed test
Test your Shopify store's speed on mobile and desktop. You get the PageSpeed Insights score, real-user Core Web Vitals from Chrome, the apps and scripts slowing the store down, and an honest estimate of whether a headless build would help.
Data from Google PageSpeed Insights and the Chrome UX Report · Free, no sign-up
3.5%
lower conversion, on average, for every 100 milliseconds slower a Shopify store loads.
Shopify, Store speed and conversion (2026)8.4%
more retail conversions after mobile sites loaded 0.1 seconds faster.
Deloitte and Google, Milliseconds Make Millions (2020)2.5×
higher ecommerce conversion rate for a site that loads in 1 second than one that loads in 5.
Portent, Site speed and conversion rate (2022)8%
more sales for Vodafone in an A/B test that made Largest Contentful Paint 31% faster.
web.dev, Vodafone case study (2021)123%
more likely to bounce: a mobile visitor whose page takes 10 seconds to load instead of 1.
Google and SOASTA Research (2017)9.2%
higher average order value for retailers from the same 0.1-second gain.
Deloitte and Google, Milliseconds Make Millions (2020)53%
more revenue per visitor for Rakuten 24 after it improved its Core Web Vitals.
web.dev, Rakuten 24 case study (2022)30%
lower conversion for Shopify stores with a 2.5-second Largest Contentful Paint than for those at 1.5 seconds.
Shopify, Store speed and conversion (2026)
Want a second pair of eyes on these results? We fix Shopify speed on the theme you have, and tell you honestly when a rebuild is worth it.
Book a callWhat the speed test checks
Enter any page of a Shopify store. The test first confirms the site runs on Shopify and which theme it uses, then runs four checks:
- Lighthouse lab test: Google PageSpeed Insights loads the page once on a simulated phone and once on desktop, and scores it from 0 to 100.
- Real-user Core Web Vitals: 28 days of Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift from Chrome users, for the page or, with less traffic, the whole site.
- What slows it down: the apps, scripts, images and theme code with the largest estimated savings, with the change that fixes each one.
- Headless estimate: how much of the measured saving a fix on your current theme could deliver, against what only a custom storefront would change, with the assumptions listed.
A test takes 10 seconds to 2.5 minutes, because Google loads the page in a real browser. Results are saved for 24 hours, so testing the same page again shows the saved result.
Lab score or real users: which one matters?
The Lighthouse score comes from one simulated visit on a mid-range phone with a throttled connection. It's good for finding causes and comparing changes, but it moves from run to run.
Google's search ranking uses Core Web Vitals from real Chrome visits instead. A page passes when 75% of visits have Largest Contentful Paint within 2.5 seconds, Interaction to Next Paint within 200 milliseconds and Cumulative Layout Shift of 0.1 or less. A store can score under 50 in the lab and still pass with its real customers, and the reverse.
Why Shopify stores get slow
Shopify serves pages and images from a fast global network, so most slowness is added on the store itself:
- Apps that add scripts to every page, such as reviews, chat, upsells, analytics and tag managers. Removing an app can leave its code in the theme.
- Large images without a width that matches the layout, especially in the first screen.
- Theme JavaScript for sliders, page builders and inline scripts that delays interaction.
- Fonts and banners that move the page as they load.
Most of these are fixed on the current theme. Our Shopify speed optimization service starts from real-user measurement and keeps measuring after each change.
When headless helps, and when it doesn't
A headless storefront replaces the theme's HTML, JavaScript and app embeds with code you control. That only pays off on speed when the theme's own code is the bottleneck. If apps and images cause most of the delay, a rebuild that adds the same scripts back won't be faster.
The estimate in the report separates the two. For the wider trade-offs, read how to choose a headless Shopify agency or see our headless Shopify agency work.
Use it from your AI assistant
The same speed test runs as a free MCP server at https://tools.skaidigital.com/mcp, with no account or key. AI assistants that support remote MCP servers can check a store's speed, detect whether it runs on Shopify, and compare Shopify plan fees.
claude mcp add --transport http skai-shopify-tools https://tools.skaidigital.com/mcp{
"mcpServers": {
"skai-shopify-tools": {
"url": "https://tools.skaidigital.com/mcp"
}
}
}{
"servers": {
"skai-shopify-tools": {
"type": "http",
"url": "https://tools.skaidigital.com/mcp"
}
}
}Frequently asked questions
Is the Shopify speed test free?
Yes. There is no sign-up. A fair-use limit per visitor keeps it free for everyone, and results are saved for 24 hours.
Why is my Shopify PageSpeed score so low on mobile?
The mobile test simulates a mid-range phone on a throttled connection, so heavy scripts and large images cost far more than on desktop. Check the real-user Core Web Vitals too: they are what Google ranks on.
What is a good PageSpeed score for a Shopify store?
Lighthouse rates 90 to 100 as good, 50 to 89 as needs improvement and under 50 as poor. For search, passing Core Web Vitals with real users matters more than the lab score.
Which apps slow down a Shopify store?
Any app that loads scripts on every page can. The report names the apps and third-party scripts with the most main-thread work and download size on your store, so you can see which ones cost the most.
Does the speed test work on headless and Hydrogen stores?
Yes. It detects Hydrogen and Oxygen storefronts, and storefronts on other hosts that load Shopify assets, and tests them the same way.
Will going headless make my Shopify store faster?
Only if the theme's own code is what slows it down. The report's headless estimate compares the savings you can make on your current theme with those only a custom storefront would change.
Can I run the speed test from ChatGPT, Claude or Cursor?
Yes, from any assistant that supports remote MCP servers. Add https://tools.skaidigital.com/mcp; it needs no account or key.
