Carbon
Carbon is a Astro theme by Lexington Themes (Paid). Tested on 2026-09-12 with Google Lighthouse via PageSpeed Insights on its own demo store, it scores 77 for mobile speed and 98 for desktop speed, 66/66 for SEO and 100/100 for accessibility (mobile/desktop, 0–100).
Mobile77
Desktop98
Scores
| Mobile | Desktop | |
|---|---|---|
| Speed | 77 | 98 |
| SEO | 66 | 66 |
| Accessibility | 100 | 100 |
| Best practices | 100 | 100 |
Single preset · measured 2 times since 2026-09-12 · Lighthouse via PageSpeed Insights · 0–100, 90+ is good.
Why not 100 — Carbon home page
Mobile
Speed 77 · 23 points to gain
- −21 Largest Contentful Paint medium effort
- −1.1 First Contentful Paint medium effort
- −0.5 Speed Index medium effort
- 150 ms Reduce unused JavaScript high effort
SEO 66 · 34 points to gain
- −33.6 Page is blocked from indexing low effort
Desktop
Speed 98 · 2 points to gain
- −1.5 Largest Contentful Paint medium effort
SEO 66 · 34 points to gain
- −33.6 Page is blocked from indexing low effort
Presets and pages
| Preset / page | Speed | SEO | A11y | Speed | SEO | A11y | Tested |
|---|---|---|---|---|---|---|---|
| mobile | desktop | ||||||
| Carbon default demo ↗ | 77 | 66 | 100 | 98 | 66 | 100 | 2026-09-12 |
| home ↗ | 77 | 66 | 100 | 98 | 66 | 100 | 2026-09-12 |
Show this score on your site
A live badge: it always shows Carbon's current score and links back here. Paste this where the theme is sold or documented.
<a href="https://themestested.com/theme/astro/carbon"><img src="https://themestested.com/badge/astro/carbon.svg" alt="Carbon speed score on Themestested" height="20"></a>
Add ?device=d for the desktop score, or ?metric=seo / ?metric=a11y for SEO or accessibility.