Website speed matters. Fast-loading sites perform better on all fronts: better user experience, higher conversions, more engagement, even higher search rankings. If you’re after mobile traffic (everyone is), site speed becomes even more important. No one wants to download a 4MB website on their smartphone, but most sites are that way. Your website can be different.

How fast is fast enough?

While 1-second load time would be nice, if you manage to get a load time under 3 seconds, you’re doing fine. If it’s under 7 seconds, it’s okay too (but you have to try to improve it). Over 10 seconds and you’re losing money in noticeable quantities.

According to Strangeloop, who tested the load times of the top 2,000 retail websites, web pages keep getting bigger, and the average site takes 10 seconds to load. Typical leading eCommerce sites take 4.9 seconds to serve usable content.

So how fast should your site be? While Jakob Nielsen says people can handle up to 10 second load time, consider this:

  • 47% of people expect a web page to load in two seconds or less.
  • 57% of visitors will abandon a page that takes 3 seconds or more to load.
  • At peak traffic times, more than 75% of online consumers left for a competitor’s site rather than suffer delays.
  • According to this scientific study tolerable waiting time for information retrieval is approximately 2 seconds. Adding feedback, like a progress bar, can push tolerable waiting time to 38 seconds (so if your site is slow, add progress bars or equivalent).
  • A site that loads in 3 seconds experiences 22% fewer page views, a 50% higher bounce rate, and a 22% fewer conversions than a site that loads in 1 second. While a site that loads in 5 seconds experiences 35% fewer page views, a 105% higher bounce rate, and 38% fewer conversions.
  • 8% of people cite slow loading pages as a key reason for abandoning their purchase.


Only 25% of the Alexa 2000 uses a CDN. A fifth of sites fail to implement relatively simple performance-enhancing techniques. Some sites are of course fast. The fastest of them (according to Strangeloop study) were (1.02s), (1.9s), (1.95s). Amazon’s page load time was 3.26s.

Tools to analyze your site speed:

A thing to remember here is that scores don’t matter – it’s how fast your site is what makes a difference. These scoring tools let you look at potential issues and advise on best practices, but they will not solve your site’s problems for you.

How to make Google Analytics speed tracking more accurate

You’ve probably seen that Google Analytics will tell you your site speed, page speed etc. Pretty useful stuff. I urge you not to just look at average page load time, but go deeper (e.g. look at the Distributions tab to see page load speed distributions). ‘DOM Timings’ reports are useful as they show how long it takes for your pages to become usable.

Its’ pretty accurate since all load speed data in Google Analytics is taken from users’ browsers. The problem is that it only takes in data from about 1-5% of the visits, and hence it’s often not a statistically valid sample size. Instead of 5%, you could store it for 100% of visitors without any downsides. You only need to add this little line to your Google Analytics script:

_gaq.push([‘_setSiteSpeedSampleRate’, 100]);

Add it above the ‘trackpageview’ line in your Google Analytics code (hat tip to Dan Barker). Make sure you don’t break your Google Analytics code when adding this :)

Note that not all browsers support it (Safari), you will never see a 100% sample rate, but this will increase it significantly.

Impact on conversions

Main point: faster sites get higher conversions.

Check out these studies:

  • Conversion rate increases 74% when page load time decreases from 8 to 2 seconds (real user monitoring data from 33 major retailers)
  • Aberdeen Group study showed that a one second delay in page load time equals 11% fewer page views, a 16% decrease in customer satisfaction, and 7% loss in conversions.
  • One guy got an 8.47% conversion rate improvement by moving his landing page onto a faster host.
  • Shopzilla sped up their site by 5 seconds and increased the conversion rate 7-12%.
  • Shaving 2.2 seconds off Mozilla’s landing pages increased download conversions by 15.4%, which they estimate will result in 60 million more Firefox downloads per year.
  • Amazon reported already in 2006 that they got 1% revenue increase for every 100ms of improvement.

What will a 1-second delay cost you? Find the answer on the image below:


Image credit

Tagman has a conversion loss calculator so you can work out how much revenue you could gain by speeding up your site.

Are you thinking about mobile users? You should.

Let me say that I have Google Analytics access to hundreds of sites across the world. I see how many mobile users there are on these sites, and I always look at the growth rate. In my experience, for most sites in the US mobile visitors add up to around 30%-40% of total viewers. The trend is up everywhere. Back that with the global statistics that say web surfing on mobile devices will surpass desktop computers by 2015, and you have a serious case on your hands.


Mobile users usually have slower connections, but they expect sites to load just as fast. To be precise, 85% of mobile users expect pages to load as fast or faster than they load on the desktop.

Here are 3 high quality articles on improving mobile site performance:

11 Low-Hanging Fruits for Improving Site Speed

#1 Start using a CDN (Content Delivery Network)

It’s so worth it, especially if you have a decent amount of traffic. Your audience will thank you with extra dollars.

Check out these options:

  • MaxCDN – Lots of people say good things.
  • CacheFly – Another trustworthy provider.
  • Cloudflare. Part CDN, part security tool. I use it on ConversionXL.
  • Inscapsula – similar to Cloudflare, but has shown to offer a much better level of security / protection according to research.

Here’s a great article on how to pick a CDN.

#2 Host your static files in the cloud that uses a CDN

Serve static content from a cookieless domain, backed by a CDN. Why cookieless domains? Every time a browser sends an HTTP request, it has to send all associated cookies that have been set for that domain and path along with it. Static content, such as images, javascript and CSS files, don’t need to be accompanied by cookies. You can decrease latency by serving static resources from a domain that doesn’t serve cookies.

Check out these 2 options:

#3 Install Google PageSpeed on your server

Tell your web host guys to set it up, you’ll love the results.

PageSpeed improves web page latency and bandwidth usage by changing the resources on that web page to implement web performance best practices. It will automatically apply web performance best practices to web pages and associated assets (CSS, JavaScript, images) without requiring that you modify your existing content or workflow. Plug’n’play.

#4 Tell your hosting provider that you want Memcached installed

Memcached is an open source high-performance distributed memory object caching system intended for use in speeding up dynamic web applications by alleviating database load.

Consult with your system admin first about your particular setup, but in most cases Memcached will be a great help (or alternatively look at Redis).

Unlike PageSpeed, this doesn’t do anything upon installing, so you need to configure your sites to use it. If you use WordPress, it plays nicely with W3 Total Cache plugin and you can set Memcached to do the caching.

#5 Optimize your images

Images can be large, and make your website slow to load. That’s why you need to reduce the file size of your photos that you use on your blog posts and other content, logo files, graphics etc. The good thing is that you can significantly reduce image size without compromising quality.

If you use WordPress, use a plugin like EWWW Image Optimizer which optimizes your images as you upload them (can also optimize them in bulk in Media Library).

Everybody else check out Kraken as a great image optimization service.

#6 Use a fast web host

Not all web hosts are made equal. In fact, your web host makes a huge difference.

If you have a decent amount of traffic, you should not be on hosts like Bluehost, Hostgator, GoDaddy and other low budget web hosts like that.

  • WP Engine – Web hosting made for WordPress. Blazing fast, fanatic support, stuff that dreams are made of. If you run WordPress and want a fast site, this is it.
  • LiquidWeb – Shared hosting, dedicated hosting, cloud hosting, CDN. They have it all.
  • SingleHop – Best dedicated server host I’ve come across.
  • Hetzner – Best deals on dedicated servers.
  • Storm on Demand – The best priced cloud hosting service out there. Runs ConversionXL too. Great support.

#7 Minimize round-trip times (RTTs)

RTT refers to all the requests required when a user accesses your website. This is not a size of file issue, but a number of requests issue. Each asset that needs loading – css files, javascript files, images files etc – is requested individually. So your browser sends a request to the web server, which sends information back. The same for each file. That’s why an important strategy for speeding up web page performance is to minimize the number of round trips that need to be made.

Google has a handy manual for doing it all. Here’s a quick summary (have your web guys take care of it):

  • Combine all your javascript files into one to minimize requests. If you’re technically inclined, check out Google Closure Compiler.
  • Combine images with CSS sprites. The higher the number of images used on a page, the more roundtrips there are between visitor’s browser and the web server. Ideally you merge all tiny background images into one, and use CSS to show them. Your front-end developer (CSS guy) should take care of it. Some tools to create CSS sprites: Compass, SpritePad, Spriteme.
  • Avoid CSS @import. Instead of @import, use a tag for each stylesheet. This allows the browser to download stylesheets in parallel, which results in faster page load times.
  • Minimize DNS lookups. Avoid using multiple domain names when loading a site.
  • Minimize redirects. If needed, always use http redirects instead of javascript.

#8 Use caching (plugins)

Many caching tools will already take care of the issues mentioned in step 7. If you use WordPress, you should really take a look at W3 Total Cache plugin.

#9 Compress your website with gzip

Compression reduces response times by reducing the size of the HTTP response. Gzipping generally reduces the response size by about 70%. Some caching extensions / plugins do it automatically, sometimes you need to set it up manually at the web server level. Here’s one of many millions of manuals on how to do it.

#10 Add an Expires header

Browsers use cache to reduce the number and size of HTTP requests and hence making web pages load faster. A web server uses the Expires header in the HTTP response to tell the browser how long a component can be cached. For static components: implement “Never expire” policy by setting far future Expires header, and for dynamic components use an appropriate Cache-Control header to help the browser with conditional requests.

While most caching systems take care of it, you need to look into it.

#11 Switch off all the plugins you don’t need or use

I see a lot of WordPress and other sites that have a ton of plugins / extensions installed that are actually not used. Many of them require loading different css and javascript files – all that slows down your site. Perform a plugin audit and switch off all the plugins you don’t use.


Improving site speed is part of conversion optimization. It’s often a low-hanging fruit that you can get done right away – improving user experience and revenue at the same time.

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