WordPress median mobile JS payload is 528 KB — smaller than Wix (1,462 KB) and Squarespace (1,314 KB), yet WordPress performs worse in the field
Created 2026-05-22
Claim (2024 + 2025 Web Almanac, CMS chapter, Fig. 12.12):
| CMS | Median mobile JS (KB) | Median desktop JS (KB) | Lighthouse mobile (2023→2024→2025) |
|---|---|---|---|
| WordPress | 528 | 565 | 33 → 38 → 41 |
| Wix | 1,462 | 1,461 | ~50 → 55 → 64 |
| Squarespace | 1,314 | 1,309 | – → ~30 → 32 |
| Drupal | 471 | 479 | – → ~38 → 40 |
| Joomla | 386 | 409 | – → ~38 → 40 |
| Webflow | n/a (not broken out 2024) | – | n/a → n/a → 58 |
| Duda | (not in JS chart) | – | – → 59 → 57 |
| Shopify | – | – | – → – → 52 |
Confidence: Verified.
Diagnostic punchline: WordPress ships less JavaScript at the median than Wix, Squarespace, or Shopify — yet performs worse in the field. The "WordPress is heavy" intuition is wrong at the median; what's heavy is TTFB plus the long-tail distribution (75th-90th-percentile WordPress sites drag the platform mean down).
Why this matters for sales: never tell a client "WordPress is slow because it's bloated JavaScript." The honest answer is "the typical WordPress configuration on commodity hosting fails CWV" — see WordPress CWV gap causal decomposition (May 2026): ~40-50% hosting/TTFB, ~20-30% page builders, ~15-20% plugins, ~5-10% core, ~5-10% theme.