TTFB distribution
How TTFB is distributed across real-user data, plus pass-rate breakdown.
At a glance the headline numbers for TTFB distribution
How TTFB is distributed across real-user data, plus pass-rate breakdown.
TTFB Distribution page loads across good, needs improvement and poor
TTFB 665ms. p75 1.1s. p99 4.1s. 59.3% pass.
TTFB Pass Rates share per category
TTFB passes on 59.3% of sites. 29.5% need improvement, 11.2% fail.
Why this matters for the Core Web Vitals, and where to start fixing it
Time to First Byte is how long the browser waits for the server to start replying. It is a diagnostic metric, not a Core Web Vital, but it is the foundation the others are built on: nothing can render until the first byte arrives, so a slow TTFB pushes back every paint that follows. The causes are on the server and the network, slow backend processing, no caching, or a long trip to a distant origin.
Start by getting a fast, cacheable response out the door. Cache full pages where you can, put a CDN in front so visitors are served from nearby, and keep the backend work on each request small. Early Hints use that wait: the browser can start fetching critical resources while the server is still building the page.
How are sites doing on TTFB?
59.3% of sites have a good TTFB. The typical site sits at 1.1s at the 75th percentile; the slowest 1% pass 4.1s.
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.