Time to First Byte (TTFB)

Time to First Byte (TTFB) is the time between a browser requesting a page and receiving the first byte of the response from the server. It measures how responsive your server and network are, and it sets the floor for every other loading metric that follows.

Written by Paul Hoda, SEO consultant since 2005. Last updated 8 November 2026.

What TTFB includes

TTFB is not just server thinking time. It covers several stages that happen before any content arrives:

  • Redirects, if the requested URL forwards somewhere else.
  • DNS lookup: turning the domain name into an IP address.
  • Connection and TLS negotiation for HTTPS.
  • Server processing: running code, querying the database and building the HTML.
  • The first part of the response travelling back over the network.

Because all of these add up, a fast server can still show a poor TTFB if visitors are far away or the page sits behind a chain of redirects. Dynamic pages that are built fresh for each request, such as search results or personalised content, usually have a slower TTFB than cached pages.

What is a good TTFB?

Google’s web.dev guidance suggests aiming for a TTFB of 0.8 seconds or less at the 75th percentile of real visits, with anything above 1.8 seconds considered poor. TTFB is not one of the Core Web Vitals, but it feeds directly into them.

Every millisecond spent waiting for the first byte delays First Contentful Paint.

That in turn pushes back Largest Contentful Paint, the moment the main content appears.

Why TTFB matters for SEO

A slow TTFB makes pages feel sluggish to users and can drag down your Core Web Vitals, which form part of Google’s page experience signals. It also affects crawling. Google has said that when a server responds quickly, Googlebot can fetch more pages, while slow responses can reduce how much it crawls. On large sites this links TTFB to crawl budget.

How to measure and improve it

  1. Check field data in PageSpeed Insights or the Chrome UX Report, and lab data in browser developer tools (the Network tab shows a Waiting or TTFB figure).
  2. Use full-page caching so the server sends stored HTML instead of rebuilding each page.
  3. Put a content delivery network in front of the site to serve visitors from nearby locations.
  4. Remove unnecessary redirects, especially between http, https, www and non-www versions.
  5. Upgrade underpowered hosting and optimise slow database queries or heavy plugins.
  6. Enable modern protocols such as HTTP/2 or HTTP/3 to speed up connections.

Common mistakes

Testing only from one location near the server hides problems for distant visitors. Lab tests from a single run can also mislead, so compare them with field data from real users over several weeks. Another mistake is judging TTFB on a logged-in admin view, which often bypasses caching. Finally, do not chase a perfect TTFB at the expense of everything else: it is one part of overall page speed, not the whole picture.

Further reading: web.dev’s guide to Time to First Byte.

Key Takeaways

  • TTFB measures how long the browser waits for the first byte of a response.
  • It includes redirects, DNS, connection setup and server processing time.
  • Google suggests aiming for 0.8 seconds or less for most real visits.
  • A slow TTFB delays FCP and LCP and can reduce how much Googlebot crawls.
  • Caching, a CDN and fewer redirects are the most common fixes.

Related Terms

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