Top 5 Website Performance Testing Tools

Among the many important ranking factors there's speed.

Searchmetrics ranking factors report found that the top 10 highest ranking sites were also the fastest.

Moz found out that it's not the general speed of the page, but the Time To First Byte that matters

• What Is Time To First Byte, And How To Improve It

The tools to measure performance are listed in no particular order. Running a test on each one is very fast. It's a good practice to test your site in all of these tools to get a good feel for what everyone agrees on needs improvement.

1. Pingdom

Emphasizes page loading time.

Grades elements and lists them from worst to good:

Each element can be expanded and has resource-specific recommendations.

2. GTmetrix

GTmetrix doesn't use its own grading score but instead reports both Google's PageSpeed and Yahoo's YSlow:

Results are sorted by the impact they have on the scores:

Registered users can record a video of the page loading and play it back at full speed or slowed down up to 4 times.

3. Google PageSpeed Insights

Doesn't report on absolute speed performance in seconds, but in Google's relative PageSpeed scale. If you score 60/100 your site is faster than 60% of other sites; only 40% other sites are faster.

In the same test Google PageSpeed Insights reports on how the site would perform when fetched by a mobile device. And it shows you how the site would render on mobile:

 

Feedback is organized in Should Fix and Could Fix:

Sometimes these recommendations can be in conflict with other rules. E.g., to speed up rendering a page some CSS can be placed inline -- but when done so you may get a warning to place styling inline.

4. Nibbler

More of an all-in-one site report than a speed test, but with some very nice features.

Besides the given URL the tool will test 5 random pages and use the aggregate information for scoring. Scoring includes how the site is marketed, social performance, etc.

 

5. Webpagetest

One of the more technical tools. Very strong on reporting Time To First Byte and grading that time.

Can be set to do two runs: first view and second view, when some content will have been cached by both the server and the browser. Uses it's own relative Speed Index which scores how fast the page visually loads.