Two websites can look identical, yet one feels instant and the other feels sluggish before a single image even appears. A big part of that difference comes down to one number most people never see: TTFB, or Time To First Byte. It measures how quickly a server starts responding — and it shapes how fast your whole site feels, plus how well it ranks. So what counts as a good TTFB, how do you test it, and how do you improve it? Here's the plain-English guide.

What is TTFB?

TTFB (Time To First Byte) is the time between your browser making a request and receiving the very first byte of the response back from the server. It's essentially the waiting time before any content can start loading — the gap between "I asked for this page" and "the server started answering."

That single measurement rolls up several steps: the DNS lookup to find the server, establishing the connection (including the secure handshake), the server's time to process the request, and the network latency for that first byte to travel back. If any of those is slow, TTFB rises — and everything the visitor sees is delayed, because nothing can render until that first byte arrives.

What is a good TTFB? The benchmarks

Here's a practical scale for TTFB:

  • Under 200ms — excellent. The server is responding almost instantly. This is the target to aim for.
  • 200–500ms — good. Perfectly acceptable for most sites; visitors won't notice a delay.
  • 500–800ms — needs improvement. Starting to feel sluggish; worth investigating.
  • Over 800ms — poor. A noticeable lag before anything loads, and a drag on both experience and SEO.

As a rule of thumb, aim to keep your server's response time under 200ms where you can, and your overall TTFB comfortably under 500–800ms. Google's performance tools flag slow server responses in roughly this range, so staying under it keeps you on the right side of their guidance.

Why TTFB matters

TTFB isn't just a vanity metric — it has real consequences:

  • It sets the ceiling for your whole page speed. Nothing can load until the first byte arrives, so a slow TTFB delays everything that follows.
  • It affects SEO and Core Web Vitals. TTFB feeds directly into Largest Contentful Paint (LCP), one of Google's Core Web Vitals ranking signals. A slow server drags LCP down and can hurt your rankings.
  • It affects bounce rate. Visitors judge a site in the first moments. A long wait before anything appears sends people away before they've seen your content.

In short, a fast TTFB makes your site feel quick, rank better, and keep more visitors.

How to test any site's TTFB

You don't have to guess — TTFB is easy to measure:

  • Use a free online speed test. Our free Site Speed (TTFB) tool measures a site's Time To First Byte directly from our servers, so you can check any domain in seconds and see exactly how its server is performing.
  • Use your browser's DevTools. Open Developer Tools (F12), go to the Network tab, reload the page, click the main request, and look at the "Waiting (TTFB)" timing — it shows the exact figure for that load.

Testing from a couple of sources gives you a clearer picture, since your own location and connection influence the number too.

What affects your TTFB

If your TTFB is high, the cause is usually one of these:

  • Server performance. An overloaded or underpowered server takes longer to process each request.
  • Hosting quality. Cheap shared hosting often has slower response times than a dedicated or well-optimized setup.
  • Distance from the visitor. The farther the server is from the user, the more latency is added — a visitor across the world waits longer.
  • No caching. Without caching, the server rebuilds each page from scratch every time, adding processing time.
  • Slow backend code or database queries. Unoptimized queries and heavy application logic directly inflate server processing time.
  • No CDN. Without a content delivery network serving content from nearby locations, everyone hits your origin server directly.

How to improve TTFB

The good news is that TTFB is very improvable:

  • Add caching. Page and object caching let the server return a ready-made response instead of building it each time — often the single biggest win.
  • Use a CDN. A content delivery network serves content from locations near each visitor, cutting latency dramatically.
  • Upgrade your hosting. Faster, better-resourced hosting directly lowers server response time.
  • Optimize your backend. Speed up slow database queries and heavy code, which cut straight into processing time.
  • Reduce redirects. Each redirect adds a round trip before the real response begins.

If your TTFB is consistently high and it's dragging your whole site down, our guide on why a website loads slowly covers the broader picture, and a very high TTFB can even tip over into timeout errors like a 504 Gateway Timeout when the server takes too long to respond.

The bottom line

TTFB — Time To First Byte — is the waiting time before a server starts responding, and it sets the pace for your entire page. Aim for under 200ms for an excellent result, keep it under 500–800ms to stay competitive, and treat anything over 800ms as a problem to fix. Test any site's TTFB for free with our Site Speed tool, then improve a slow one with caching, a CDN, better hosting, and backend optimization. Get that first byte out fast, and everything else about your site feels faster too.