How to speed up your online store (and why Google cares)

A slow store loses twice: Google ranks it lower, and the visitors who do arrive leave before they buy. The good news is that most store speed problems come from a short list of causes, and the fixes are not complicated.

How Google measures speed

Google uses Core Web Vitals, three measurements taken from real visitors' browsers:

• Largest Contentful Paint (LCP): how long until the main content (usually the hero image or product image) is visible. Target under 2.5 seconds.
• Interaction to Next Paint (INP): how quickly the page responds when someone taps or clicks. Target under 200 milliseconds.
• Cumulative Layout Shift (CLS): how much the page jumps around as it loads. Target under 0.1.

These are reported in Google Search Console and in the PageSpeed Insights tool. Test on mobile, because that is where most shoppers are and where scores are lowest.

The usual causes, in order

1. Images

The single biggest cause. A product photo uploaded straight from a camera can be several megabytes; the page needs a version a tenth of that size. Fixes: resize to the largest size actually displayed, compress, use modern formats (WebP or AVIF), and lazy-load images below the fold. Shopify does much of this automatically if the theme is built well; WooCommerce needs an image optimisation plugin or a CDN that does it.

2. Too many apps and scripts

Every app adds JavaScript. Reviews, pop-ups, chat, analytics, heat maps, currency converters, upsells: each one loads on every page. Audit them. Remove what you do not use, and for the rest, check whether the app loads only where needed.

3. Heavy themes

Some themes ship with every feature imaginable and load all of it whether you use it or not. Lean, well-coded themes make a large difference. If your theme is old, updating or replacing it is often the biggest single improvement available.

4. Hosting (WooCommerce)

Shared hosting at a few pounds a month cannot serve a busy store quickly. Managed WordPress hosting with server-level caching and a CDN transforms WooCommerce performance. This is one of the trade-offs we discuss in Shopify vs WooCommerce.

5. Fonts

Custom web fonts delay text rendering. Use one or two font families, load only the weights you need, and set them to display fallback text immediately.

6. Third-party embeds

Instagram feeds, YouTube videos, maps and social widgets are heavy. Load them on demand or replace with a static image that links out.

7. Layout shift

Images without defined dimensions, banners injected above content and late-loading fonts cause the page to jump. Give images width and height, reserve space for dynamic content, and avoid pop-ups that push the page down.

A practical order of work

1. Run PageSpeed Insights on your home page, a category page and a product page, on mobile. Note the LCP element and the largest opportunities listed.
2. Fix images site-wide.
3. Remove unused apps and plugins.
4. Replace or update a heavy theme.
5. For WooCommerce, upgrade hosting and add caching and a CDN.
6. Re-test. Then go through fonts, embeds and layout shift.

Why it matters beyond rankings

Speed compounds. Faster pages mean more products viewed, fewer abandoned checkouts and better ad performance, because ad platforms also factor in landing page experience. It is one of the few changes that improves SEO, paid ads and conversion at the same time. Our guide on reducing cart abandonment lists speed among the top fixes for a reason.

If your store is slow and you are not sure where to start, a speed audit is a standard part of our eCommerce work. Read about our eCommerce service or request a quote.

Frequently asked questions