How to check your Shopify store speed, and what to do

A slow Shopify store costs you sales quietly. Nobody fills in a form to tell you the checkout took too long, they just leave. The tricky part is that your store often feels fast to you, because you're testing it on good broadband, on a laptop, already logged in. Customers on a train with patchy 4G get a different experience. Before you can fix anything, you need an honest read on how slow things actually are, and which parts matter.

How do I check my Shopify store speed

Use Google PageSpeed Insights first. It's free, it's built on the same data Google uses to rank sites, and it gives you both a lab test (a simulated load) and, if your site gets enough traffic, real user data from actual visitors over the past 28 days. That real user data matters more than the lab score, because it reflects what customers on different devices and connections actually experience.

Other tools worth knowing:

• Shopify's own Online Store Speed report (Settings > Online Store Speed, or under Analytics). It's built for Shopify specifically, so it understands theme structure and apps in a way generic tools don't.
• GTmetrix. Good for a visual waterfall of what's loading and in what order, useful once you want to see which specific file or app is slow.
• WebPageTest. More technical, more detail than most business owners need, but good if you want to test from a specific location or device.

For a first check, PageSpeed Insights and Shopify's own report will tell you almost everything you need. Run both. If they disagree wildly, trust the one with real user data.

Which speed numbers actually matter for sales

Tools throw a lot of numbers at you. Most of them don't matter much to a business owner. Three do:

• Largest Contentful Paint (LCP): how long until the main content of the page (usually your hero image or product photo) is visible. This is the number most closely tied to whether a visitor thinks the page has "loaded". Anything over 2.5 seconds starts to hurt.
• Interaction to Next Paint (INP): how responsive the page feels when someone taps a button or adds to cart. A slow INP feels like the site is ignoring you. This one matters a lot on mobile.
• Cumulative Layout Shift (CLS): whether things jump around as the page loads, images popping in late and pushing the "Add to basket" button down just as someone tries to click it. Annoying, and it costs you accidental mis-clicks and trust.

Ignore the overall letter grade some tools give you. A page can score a C and convert perfectly well if LCP and INP are solid. Focus on the specific numbers above, and check them separately for mobile and desktop, because mobile is nearly always worse and for most Shopify stores it's the majority of traffic.

Why is my Shopify store slow

Once you've got numbers, the next question is what's causing them. In most Shopify stores we look at, the same three culprits show up.

Apps. Every app you install adds its own script to the page, and most of them load on every page, not just the ones where they're needed. A reviews widget, an upsell pop-up, a size guide, a loyalty programme: each one is a small tax on load time, and they add up fast. The fix isn't always "delete the app". Sometimes it's asking whether it needs to load on every page, or whether a lighter alternative does the same job.

Images. Large, unoptimised product photos are the single biggest cause of slow LCP scores. A photo straight off a DSLR or a phone can be 5 to 10 times larger than it needs to be for the web. Shopify does some automatic compression, but it won't fix badly sized source images or the wrong file format.

Theme bloat. Older themes, or themes that have been customised by several different people over the years, often carry code nobody uses any more: old sections, unused CSS, leftover scripts from an app you uninstalled eighteen months ago. None of it shows on the page, but it still has to load.

It's worth saying plainly: the fix depends on which of these three is actually your problem, and that depends on your specific theme, app list and image library. A generic "10 tips to speed up Shopify" article can't tell you that. A proper audit of your store can.

Should I trust my theme's built-in speed score

Some themes show their own speed rating in the Shopify admin or in their marketing. Treat this with caution. It's often measured on a stripped-down demo store with no apps installed and stock images, which is nothing like your actual store once you've added reviews, upsells, tracking pixels and real product photography. A theme being fast in theory doesn't mean your version of it is fast in practice. Always test your live store, not the theme's reputation.

What should I actually do with the results

Once you've got real numbers, here's a sensible order of operations:

• Start with images. It's the lowest-risk fix and often the biggest single improvement. Compress and correctly size product photos, use Shopify's native image handling rather than hotlinking from elsewhere, and avoid loading huge hero banners that aren't actually needed at that size.
• Audit your apps. List every app installed, check what it's actually doing for conversion, and remove anything you installed once and forgot about. For the ones you keep, check whether they can be set to load only on relevant pages.
• Look at the theme last. This is the one that usually needs a developer, because stripping out unused code without breaking something takes care and testing. It's not a five-minute job, but it's often where the remaining gains are once images and apps are sorted.

If your numbers are borderline, say LCP sitting around 2.8 to 3.2 seconds, it's worth asking whether the fix is worth the effort right now. Speed matters more the more traffic and the more competitive your market is. A low-traffic niche store with a 3-second LCP is a different priority to a high-volume store in a crowded category where every tenth of a second is being fought over by competitors.

If you've run the checks above and you're seeing genuinely slow numbers, particularly on mobile, that's worth fixing properly rather than guessing at. We do this kind of audit as part of our Shopify work, looking at your actual apps, theme and images rather than running a generic checklist. Get the numbers first, then get a second opinion on what they mean for your store specifically.