What TTFB measures
This test asks your server for the page from several locations and times the gap between the request going out and the first byte coming back. That gap covers the DNS lookup, the connection, the security handshake and whatever your server did before it started replying.
How to read your result
Under 200 milliseconds is good, 200 to 600 is workable, and anything over 800 means visitors are staring at a blank screen before your page has even begun to arrive. A high number in one region and a low number in another points at physical distance. A high number everywhere points at the server itself, usually a database query, a bloated plugin stack or an overloaded shared host.
What to change first
Turn on full page caching so repeat requests never touch the database. On WordPress that means a caching plugin or server level caching, and it commonly cuts TTFB by more than half on the first try. If caching is already on and the number is still high, the host is undersized.
Common questions
- What is a good TTFB?
- Google treats anything under 800 milliseconds as acceptable and under 200 as good. Most well hosted cached sites land between 100 and 300.
- Does TTFB affect SEO?
- Indirectly, and strongly. Every Core Web Vitals measurement starts counting from the moment the request goes out, so a slow first byte pushes every other number up with it.
- Why is my TTFB fine for me but slow in the test?
- Your own visits are usually cached and local. The test is a cold request from far away, which is closer to what a new visitor gets.
Related tests
Run this alongside every other test in Website Speed Tests, or start from the full list of website testing tools.