A 1-second delay in page load time reduces conversions by 7%. On a store doing $50,000/month, that's $3,500/month in lost revenue from a single second. Shopify speed optimization is not an aesthetic improvement — it's a revenue lever. Here are the 12 fixes that consistently move PageSpeed scores, verified across 500+ stores.

Why Your Shopify Store Is Slow

Most slow Shopify stores have the same handful of problems: too many apps injecting JavaScript, uncompressed images, render-blocking third-party scripts, and themes that load everything at once. The good news — most of these are fixable without rebuilding the store from scratch.

The target: 90+ on desktop, 70+ on mobile (PageSpeed Insights). Most untouched Shopify stores score 30–50 on mobile. After optimization, 80–95 is consistently achievable.

The 12 Fixes

01
Convert Images to WebP
WebP images are 25–35% smaller than JPEG at equivalent quality. Shopify's CDN supports WebP delivery automatically when you upload images — but older stores often have thousands of JPEG/PNG files that predate this. Use Shopify's built-in image transformation (append ?format=webp) or upload new images in WebP format. For product images, the size reduction is dramatic.
High Impact
02
Add Explicit Width & Height to All Images
Missing width/height attributes on images cause Cumulative Layout Shift (CLS) — the browser doesn't know how much space to reserve before the image loads, so it reflows the page. CLS kills your PageSpeed score. Add width and height to every img tag in your theme's Liquid files.
High Impact — Fixes CLS
03
Lazy Load Below-the-Fold Images
Images that aren't visible on initial load shouldn't be downloaded on initial load. Add loading="lazy" to all images that appear below the fold. In Shopify Liquid, this means updating your image tags in section files. The hero/LCP image should never be lazy-loaded — that makes LCP worse. Everything else: lazy.
Medium-High Impact
04
Preload Your LCP Image
The Largest Contentful Paint (LCP) is usually your hero image. Browsers discover it late because it's in CSS or Liquid. Add a <link rel="preload"> tag in the <head> specifically for the hero image to tell the browser to fetch it immediately. This alone can improve LCP by 0.5–1.5 seconds.
High Impact — LCP
05
Audit and Remove Unused Apps
Every installed Shopify app — even ones you're not actively using — injects JavaScript and CSS into every page. A store with 20 apps typically has 15–20 additional script tags loading on every page view. Uninstall any app you haven't used in the last 30 days. Then check which remaining apps inject scripts on pages where they're not needed (many do) and use Shopify's content_for_header controls to limit their reach.
Very High Impact
06
Defer Non-Critical JavaScript
Scripts that don't need to run during initial page load should be deferred. Add defer or async attributes to non-critical script tags. In Shopify themes, this often applies to chat widgets, review carousels, and analytics scripts. These can load after the page is interactive without any user-visible impact.
High Impact — INP
07
Load Fonts Non-Blocking
Google Fonts loaded with a standard @import in CSS are render-blocking — the browser won't display text until the font is downloaded. Use the media="print" onload="this.media='all'" pattern instead. This loads the font asynchronously so the page renders immediately with a system font fallback, then swaps to the custom font.
Medium Impact — removes render block
08
Remove Unused CSS
Shopify themes ship with CSS for features you're not using — specific section styles, unused component variants, vendor prefixes for old browsers. Use tools like PurgeCSS or manually audit your theme's CSS files and remove rules that apply to no elements on your live store. Reducing CSS file size directly improves render time.
Medium Impact
09
Use Shopify's Native Image CDN
Shopify serves images via a global CDN by default — but only if you use the | image_url Liquid filter correctly with size parameters. Many older themes use hardcoded image URLs that bypass the CDN sizing. Update your Liquid image tags to use image_url: width: 800 parameters so Shopify serves the right resolution for each device.
Medium-High Impact
10
Minify Liquid, CSS, and JavaScript
Remove whitespace, comments, and unnecessary characters from your theme files. Shopify does some automatic minification, but custom theme code often ships unminified. Minifying your custom JS and CSS files reduces file sizes by 15–30%. Not a huge gain on its own, but meaningful as part of a complete optimization.
Low-Medium Impact
11
Replace Heavy Apps with Native Liquid
Some apps doing simple jobs (countdown timers, announcement bars, sticky headers, trust badges) can be replaced with a few lines of Liquid and CSS. The app version adds an external JavaScript file, a network request, and execution time. A native implementation does the same job with near-zero performance cost.
High Impact (case by case)
12
Optimise Your Theme's Render-Critical Path
The render-critical path is everything the browser needs to display the first visible part of the page. Inline critical CSS directly into the <head>, defer everything else. For Shopify themes, this means identifying the CSS rules that apply to above-the-fold content and loading them synchronously, while deferring all other stylesheet loading.
High Impact — LCP + FCP

Want us to handle the speed optimization on your Shopify store? We've taken stores from 22 to 91 — and we know exactly where your score is being lost.

Get a Free Speed Audit →

DIY vs Professional Speed Optimization

Fixes 1–3 and 5–6 are achievable without deep Shopify expertise. Image format conversion, lazy loading, and removing unused apps are well-documented and safe to attempt yourself. Fixes 7–12 require working inside theme files, modifying Liquid code, and understanding the browser rendering pipeline. Getting these wrong can break your store visually or functionally.

Professional speed optimization starts from $400 at MerchantUp. We audit every page, identify the specific bottlenecks, and implement the full set of fixes with a before/after PageSpeed report.

FS
Faizan Sadiq
Founder of MerchantUp. 500+ Shopify stores built and optimized since 2019. Previously SONEXT — Fiverr's top-rated Shopify development team.