What is TTFB?
TTFB is how long a browser waits, after asking for a page, before the first byte of the answer arrives. It includes the DNS lookup, connecting, TLS setup and the server's work.
In more detail
TTFB adds up several steps: finding the address (DNS), opening a connection, setting up encryption (TLS), and the server preparing the response. Distance matters, because every step needs a round trip.
Google's web.dev guidance treats 0.8 seconds or less as good. A slow TTFB usually points to server work (slow database queries, no caching) rather than the page's size.
Worked example
DNS lookup 20 ms, connection 30 ms, TLS setup 40 ms, server work 400 ms: the TTFB is 490 ms. Caching the page on the server, cutting server work to 50 ms, brings it down to 140 ms; the network steps stay the same.
See also
Related terms: Synthetic monitoring and Redirect chain. Free tool: Is it down?. How OwlHound helps: Website uptime monitoring. All terms: monitoring glossary.
Frequently asked questions
What is a good TTFB?
Google's web.dev guidance treats 0.8 seconds or less as good, measured for real visitors.
Is TTFB the same as page load time?
No. TTFB ends when the first byte arrives; the page still has to download, render and load its images and scripts.
Why is TTFB higher from far away?
Each step before the first byte needs a round trip, and round trips take longer over long distances. A CDN shortens them by answering from nearby.
Start watching your site in minutes
Free for up to 10 sites, no card, nothing to install. Read-only access you can revoke at any time — never passwords, never admin access.