Back in April of 2010, Google let the world know that site speed affects web search ranking. The slower your site, the worse off your SEO will be.

But that’s just the beginning. Like Google guru (and employee) Matt Cutts explained, SEO is just one reason to ramp up your site’s page speed. A recent study by RankWatch.com showed these frightening figures:

• 40% of customers will leave a site if it takes longer than three seconds to load. 80% won't be back.
• A one second delay leads to 7% loss in conversions and 11% decline in page views.
• The average online customer expects a page to load in two seconds or less.

Walmart discovered that when it increased the performance of its website by 100ms, revenue grew by one-percent. Amazon saw similar results.

But how do you know if you even have a slow site?

How to Diagnose a Slow Site

Google has a free tool called PageSpeed Insights. You can use it to test how fast your site loads.

You start by punching in your website’s URL.

Then you click the “Analyze” button and wait for the results -- a score out of 100 for both the mobile and desktop version of your site. You’ll see suggestions on what you should fix and tips on how to make the repairs.

Another great tool is the Pingdom Website Speed Test. It lets you test from different geographical locations, like New York City, Dallas, and San Jose. Just press the “Settings” button open up the dropdown.

This tool gives your website a performance grade and a breakdown on what areas of your site are holding you back.

The site’s Page Analysis tab shows which content types are taking the longest to load on your site. Just like Google’s tool, this is free to use. Pingdom does offer services that you have to pay for (like automatic, daily site tests), but you can use the free speed test as many times as you want.

How to Speed Up Your Site

Both Pingdom’s Website Speed Test and Google PageSpeed Insights will pinpoint issues on your site and organize them by seriousness, so you’ll know which problems to address first.

You probably don’t need to fix all of the issues that Google and Pingdom find. As long as your site is in the high 80s or above and loading in about two seconds, you should be good. (We tested BestBuy.com and it got a 73 out of 100 on PageSpeed and a 78 out of 100 on Pingdom, but still managed to load in well under two seconds). You might get there by fixing just the serious issues.

If your site is slow, here are the most likely reasons why:

• You have a bulky site design. Yahoo said that front-end downloads (images, scripts, stylesheets, etc.) account for 80% of a page’s download time. So one way to speed up your site is to simplify the front end. You can do that by reducing scripts, using images with smaller file sizes (think kilobytes instead of megabytes), and combining style sheets. Remember, the simpler your site’s design, the faster it’ll load.
  • Try to use just one external style sheet. This site will show you how many external CSS files your site is currently using. If you’re using more than one, consider combining them to reduce the time it takes for your page to load. 
• Your pages aren’t compressed. You can reduce the bandwidth of your site by compressing the pages, but first you’ll need to make sure your server can compress files into a zip format. Yahoo says doing this can reduce download time by upwards of 70-percent.
• Your code hasn’t been optimized. When you run a Google PageSpeed Insights test, you should see this sentence at the bottom of the Suggestions Summary: “Download optimized image, JavaScript, and CSS resources for this page.” Click on the embedded hyperlink to get an optimized version of your code.
• You aren’t using a CDN. A content delivery network (CDN) can increase site speed. The idea is pretty simple: when you use a CDN, your site’s data is copied to multiple servers located all across the country, so when a user goes to your website, the CDN’s closest server sends them your website’s data. Because the CDN’s server will be geographically closer to the user, the data should load faster.
• You have a slow server response time. According to Google, “Server response time measures how long it takes to load the necessary HTML to begin rendering the page from your server, subtracting out the network latency between Google and your server.” Ideally, this should be less than 200ms. The PageSpeed Insights test should tell you if yours takes longer than that. Reasons for an undesired response time include slow database queries, memory starvation, resource CPU starvation, slow application logic, and slow routing.
  • You can decrease your server response time by either making improvements to the hosting you are already using or by spending more on better hosting. The decision that’s right for you likely depends on how much traffic you are receiving.

We hope these tips will help you optimize your site. Even after you speed it up, you should still monitor it. Site speed can fluctuate and you don’t want to be the last one to know your site is running slow.