Cornerstone Light
Cornerstone Light is a BigCommerce theme by BigCommerce (Free). Tested on 2026-11-08 with Google Lighthouse via PageSpeed Insights on its own demo store, it scores 86 for mobile speed and 99 for desktop speed, 90/90 for SEO and 98/99 for accessibility (mobile/desktop, 0–100).
Mobile87
Desktop98
Scores
| Mobile | Desktop | |
|---|---|---|
| Speed | 86 | 99 |
| SEO | 90 | 90 |
| Accessibility | 98 | 99 |
| Best practices | 100 | 100 |
Single preset · measured 52 times since 2026-09-11 · Lighthouse via PageSpeed Insights · 0–100, 90+ is good.
Why not 100 — Cornerstone-Light home page
Mobile
Speed 87 · 13 points to gain
- −11 Largest Contentful Paint medium effort
- −0.9 First Contentful Paint medium effort
- −0.7 Speed Index medium effort
- 300 ms Reduce unused JavaScript high effort
- 150 ms Reduce unused CSS high effort
SEO 92 · 8 points to gain
- −7.7 Document does not have a meta description low effort
Accessibility 95 · 5 points to gain
- −3.3 Background and foreground colors do not have a sufficient contrast ratio. medium effort
- −1.4 Document does not have a main landmark. medium effort
Desktop
Speed 98 · 2 points to gain
- −2 Largest Contentful Paint medium effort
SEO 92 · 8 points to gain
- −7.7 Document does not have a meta description low effort
Accessibility 99 · 1 points to gain
- −1.4 Document does not have a main landmark. medium effort
Presets and pages
| Preset / page | Speed | SEO | A11y | Speed | SEO | A11y | Tested |
|---|---|---|---|---|---|---|---|
| mobile | desktop | ||||||
| Cornerstone-Light default demo ↗ | 86 | 90 | 98 | 99 | 90 | 99 | 2026-11-04 |
| category ↗ | 85 | 92 | 99 | 99 | 92 | 100 | 2026-11-04 |
| home ↗ | 87 | 92 | 95 | 98 | 92 | 99 | 2026-11-07 |
| product ↗ | 85 | 85 | 99 | 99 | 85 | 99 | 2026-11-08 |
Show this score on your site
A live badge: it always shows Cornerstone Light's current score and links back here. Paste this where the theme is sold or documented.
<a href="https://themestested.com/theme/bigcommerce/cornerstone-light"><img src="https://themestested.com/badge/bigcommerce/cornerstone-light.svg" alt="Cornerstone Light speed score on Themestested" height="20"></a>
Add ?device=d for the desktop score, or ?metric=seo / ?metric=a11y for SEO or accessibility.