# How do you test a Shopify theme for layout shift? | Theme Rank Weekly

Source: https://themerankweekly.com/shopify-theme-layout-shift-test/

Load the product page on a phone and watch for anything that moves after it appears. Google counts CLS of 0.1 or less as good. Banners and late images cause most of it.

## What good looks like

web.dev sets good Cumulative Layout Shift at 0.1 or less and poor above 0.25, at the 75th percentile of page loads.

## What to check

Announcement bars that slide in, review stars that load late, images without set sizes, and fonts that swap. A theme that stays still while it loads should rank above one with a nicer demo.

Source: [web.dev, Cumulative Layout Shift (CLS)](https://web.dev/articles/cls). Reviewed Sep 23, 2026.

## Frequently asked questions

### What matters most in a Shopify theme for a pet store?

Repeat purchase support and filtering by species, life stage, and dietary need. Pet owners buy on a cycle, so easy reordering and precise filtering beat decorative design. Test any theme with your real catalog and variant count before choosing.

### How can a pet store theme reduce returns?

Clear feeding, sizing, and suitability information on the product page prevents most wrong purchases. Look for themes with room for structured guides and reviews that mention the animal, not just star ratings.

### Should pet stores prioritize subscriptions in a theme?

Yes if food or litter is a core category. The theme should surface subscription savings clearly on product and collection pages and make managing a subscription from the account page straightforward, even when an app powers the billing.