The Real Cost of a Slow Website

The 100ms Tax

Across our 40-site analysis, we found a consistent pattern: every 100 milliseconds of additional load time reduced conversions by approximately 1.2%. That's not a rounding error. For a site doing $1M/year in revenue, a 500ms delay is costing roughly $60,000 annually.

This isn't theoretical. We measured actual conversion events — form submissions, purchases, phone calls — against Core Web Vitals data from Google Search Console and real user monitoring.

Where Speed Dies

The biggest offenders we found consistently across client sites:

• Unoptimized images — the average site was serving 4.2MB of images on the homepage. After optimization: 380KB. Same visual quality.
• Third-party scripts — analytics, chat widgets, remarketing pixels. One client had 23 third-party scripts loading on every page. We cut it to 6.
• Render-blocking CSS — page builders like Elementor and Divi load 300-500KB of CSS on every page, most of it unused.
• No caching strategy — static assets served without cache headers, forcing full re-downloads on every visit.

The Fix Isn't Hard

Most speed improvements don't require a site rebuild. Our typical engagement reduces page load by 40-60% with these changes:

• Image compression and lazy loading (WebP/AVIF)
• Script audit and defer/async loading
• Critical CSS extraction
• CDN setup and cache policy
• Font optimization (preload, swap, subset)

Speed isn't a feature. It's a tax on every conversion your site will ever produce. Pay it once or pay it forever.

The ROI on speed optimization is one of the highest in all of CRO, because it affects every single visitor. A headline change might affect bounce rate on one page. Speed affects conversion on every page, every session, every device.