“Time To First Byte” is an optimization metric that tells you the time your browser spends waiting on the web server to send back the data.
A number of factors go into the TTFB but many of those points can be improved on through optimization.
It is worth noting though that optimizing TTFB is one of the technical aspects of website optimization. If you’re not already familiar with doing extensive troubleshooting on your site, then I highly suggest you hire an expert.
I recently changed themes and part of the process of maintaining a solid site involves making sure that the theme and existing plugins all put their code in the right place and play nicely together… so I’ve been taking a close look at TTFB!
Does “Time To First Byte” (TTFB) Matter?
Some people say that “Time To First Byte” is of debatable value, but I still find it important because it fits WITH the other metrics to improve the visitor experience.
The people over at Cloudflare will tell you it’s a bad metric and, although I love Cloudflare, I disagree due to the point I stated above.
However, Moz has shown a correlation between TTFB and rankings.
Please keep in mind that correlation does not indicate causation. And TTFB is a SIGN of a well optimized site.
One of the easiest ways to measure your site’s TTFB is to visit http://webpagetest.org and test your home page, blog page, and individual post page.
Be sure to click into advanced and tell the test to run at least seven times (use an odd number) so that you get a mean value.
With a WordPress site, you will rarely hit the optimized value that WPT looks for for static content, but it will at least let you know what your current value is.
What TTFB Values Are We Looking For?
I DO like to use Moz’s recommended values as goals to achieve.
“We recommend a TTFB time of 500 ms or less. Of that TTFB, no more than 100 ms should be spent on network latency, and no more than 400 ms on back-end processing.”
The team at rackAID does a good job explaining why non-pre-cached WordPress sites have a higher TTFB.
“For dynamic content, the TTFB is often 200-500ms. The longer numbers reflect what is happening behind the scenes. Consider a WordPress Blog. When you make a request, the PHP scripts have to open a number of include files, make a connection to the database, parse the results, and send back the final HTML document. All of this takes time. So even on a well powered, lightly loaded system, TTFB numbers will almost always be higher for dynamic content than static content.”
What “Right” Looks Like On WordPress
You will find that well-optimized sites – for example, the one by Nile Flores – consistently come in well within that guideline for both homepage and individual posts.
Addressing Excessive TTFB Values
From what I’ve seen, poor time to first byte scores are most often correlated with poorly coded scripts (in your theme or plugins) and locating them should be your first line of attack.
Slow hosting hardware and overloaded servers can also contribute to higher TTFB numbers. It does make a difference! If you are using a standard low cost shared plan, your TTFB is likely being driven up by the lack of server resources you’ve purchased for your site.
You can find those suggestions, and some others, in this post on addressing high TTFB.
For cached calls to the site, server caching often trumps browser level caching and using a CDN can help offset a higher TTFB.
“Time To First Byte” is just one of many factors that go into your final ACTUAL and PERCEIVED load time numbers and ultimately whether or not you get your site to load under the 4 second mark consistently or not.
Paying attention to this value can help you head off optimization issues with your scripts, code, and hosting, which you might otherwise overlook.
And because a high TTFB often plays a role in a degraded website loading performance, you’ll want to get that fixed to keep Google (and your visitors!) happy!
~ Kim ~