Why custom-coded websites outperform templates every time
The performance gap between custom code and templates is measurable, documented, and growing. Here's what the data actually shows — and what it means for your business.
The data is clear
Google's Core Web Vitals initiative has made performance measurable and consequential. Template sites — WordPress themes, Squarespace, Wix — consistently underperform custom-coded sites.
Here's why, and what it means for you.
What "performance" actually means
Performance isn't just "how fast does it feel." It's:
- Largest Contentful Paint (LCP) — How long until the main content loads
- First Input Delay (FID) — How quickly does it respond to interaction
- Cumulative Layout Shift (CLS) — Does it jump around as it loads
Google uses these as ranking factors. Slow sites rank lower.
Why templates are slow
Unused code
Template-based sites load thousands of lines of CSS and JavaScript you're not using. A theme built for 50 different use cases carries the weight of all 50, even when you only need one.
Plugin bloat
WordPress in particular becomes slower with every plugin added. SEO plugin, form plugin, slider plugin, caching plugin... each one adds overhead.
Platform overhead
Squarespace and Wix run your site through their infrastructure with all its associated processing. You share servers with millions of other sites.
Why custom code is faster
- Only what you need — Every line of code serves a purpose
- Modern frameworks — Next.js, optimised images, edge deployment
- No bloat — No unused CSS, no redundant JavaScript
- Your own infrastructure — Optimised for your traffic patterns
The business impact
A site loading in 1.2 seconds vs 3.5 seconds:
- +20-30% better conversion rate on the faster site
- Higher Google rankings (confirmed ranking factor)
- Better mobile experience (where 60%+ of traffic comes from)
Real numbers
We've measured performance scores on client sites before and after rebuilding from templates to custom code:
- Average PageSpeed score improvement: from ~45 to ~95
- Load time reduction: often 60-70% faster
- Core Web Vitals: from failing to passing
The bottom line
Performance is no longer a nice-to-have. It's a competitive advantage, a ranking factor, and a conversion driver. Custom code delivers it consistently. Templates don't.
See our work or get in touch to discuss your site.