A slow Shopify store is a revenue problem, not just a technical one.
The maths is worth understanding before you start. If a store turning over $40,000 a month improves its mobile conversion rate by 20% — a realistic result when moving from a PageSpeed score around 40 to around 75 — that’s roughly $8,000 in additional monthly revenue with no change to advertising. The actual figure varies by store, but the direction is consistent across every optimisation we’ve done.
Here’s the practical guide, based on optimising hundreds of Australian Shopify stores.
Step 1: Measure Before You Change Anything
Go to pagespeed.web.dev and enter your store URL. Record both mobile and desktop scores, and test your homepage, a collection page and a product page separately — they often score very differently.
Mobile is the priority, since the majority of Australian ecommerce traffic arrives on a phone. Below 50 on mobile is urgent. Below 60 needs addressing.
Record the numbers somewhere. Without a baseline you can’t tell which change did the work.
Step 2: Images
Unoptimised images are the single most common cause of slow Shopify stores, and usually the easiest fix.
Every product image should be converted to WebP, compressed to under 1MB (ideally under 500KB for most products), and sized to a maximum of 2048 x 2048 pixels. TinyPNG handles compression and conversion in bulk for free.
Pay particular attention to your homepage banner. It’s the largest image most visitors load, and it’s frequently uploaded straight from a designer at full resolution.
Step 3: Apps
Every Shopify app injects JavaScript into your store, and — this is the part most owners don’t realise — uninstalling an app often leaves its code behind in your theme files.
Go to Shopify Admin, then Apps, and audit everything. Remove any app you’re not actively using. For apps you still need, check whether they load on every page or only where they’re required; a product review widget doesn’t need to run on your About page.
Step 4: Homepage Video
Autoplay video backgrounds add anywhere between 5MB and 30MB to your homepage load.
Replace them with a high-quality static image. In practice these look just as premium and load in a fraction of the time. If video is genuinely central to the brand, embed it further down the page so it doesn’t block the first render.
Step 5: Fonts
Every font weight is a separate file download. A store using three fonts at four weights each is loading twelve files before any text appears.
Limit yourself to two or three fonts and only the weights you actually use.
Step 6: Render-Blocking Scripts
This one usually needs developer help. Non-critical scripts should carry defer or async attributes so they don’t hold up the page while loading.
It’s the highest-effort item on this list and the last one to attempt — the previous five deliver most of the improvement.
What to Expect
| Change | Effort | Typical mobile score gain |
|---|---|---|
| Compress and convert images | Low | 10–20 points |
| Remove unused apps and leftover code | Low to medium | 5–15 points |
| Replace homepage video | Low | 5–15 points |
| Reduce fonts | Low | 2–5 points |
| Defer non-critical scripts | High | 5–10 points |
Applied properly, these changes typically move a store from the 30–50 range into 60–75 or above on mobile, without altering the design at all. Our speed optimisation case study shows a full before and after.
Where to Start
This week: Record your current mobile score for three page types, then compress and convert your homepage banner and top 20 product images.
This month: Audit your app list, remove anything unused, and replace any autoplay homepage video.
Next 90 days: Have a developer defer non-critical scripts, then re-measure and compare conversion rate against your baseline.
Frequently Asked Questions
What PageSpeed score should I aim for?
70 or above on mobile is a realistic target for a Shopify store with apps and imagery. Chasing 95+ usually means removing functionality that earns more than the speed gain returns.
Will a speed optimisation app fix this?
Partially. These apps handle image compression and lazy loading reasonably well, but they add another app to a store that’s often slow because of too many apps. Manual work produces better results.
Does a faster store improve SEO as well as conversion?
Yes. Page experience is a ranking factor, and faster pages get crawled more thoroughly. The conversion gain usually arrives first, within weeks; the SEO benefit builds over months.
Should I change themes to get a faster store?
Rarely worth it as a speed fix. A new theme typically inherits the same apps and images, so it ends up nearly as slow. Fix the causes first — then decide whether you still want a new theme.
How often should I re-check speed?
Every time you install an app, and at least quarterly. Stores tend to slow gradually as apps and content accumulate.
Related Reading
- Shopify Speed Optimisation Case Study: From Sluggish to Superfast
- 7 Signs Your Shopify Store Needs a Professional Audit
- The Only 5 Shopify Apps That Actually Move the Needle
HHP Design offers Shopify speed optimisation as a standalone service. Book a free store audit or get in touch for a speed check.