Testing the usability of your site is one of the smartest things you can do. Usability involves making a website's interface easier to use and simpler to understand, so that the user's experience is as enjoyable as possible. The more usable a site is, the more satisfying it will be to interact with it -- and happy visitors translate into happy customers. Ideas about what makes for the best website design don't always translate perfectly when put into practice. Elements that one person might consider easy to use may actually turn out to be confusing for someone else. In this article, we'll review 10 tools that you can use to improve your website's usability even if you're on a low budget. As designers and developers, we have a natural bias towards the way our own products function: we built them, so we know exactly how they work. Our visitors, however, don't have this advantage. This means that testing for usability is the only reliable way to find out how well a website works. Usability testing allows you to discover many ways in which your site can be improved.

How much testing should I do?

Usability testing may sound daunting, but in reality, a small investment can yield large gains. Jacob Nielsen, one of the best-known usability gurus, says: “The best results come from testing no more than 5 users and running as many small tests as you can afford.” - Jacob Nielsen (Why You Only Need to Test With 5 Users) That's right. Just 5 users will provide enough results to help you make effective updates to your website. While you could test with 15 users to find most or all problem areas on your site, testing with just 5 will uncover 85% of issues, which gives you the most value for your money. Other trouble spots can be identified by testing a subsequent round of users, and with each additional test, the number of issues uncovered will decrease. It’s important to note that the very first usability test offers the greatest insight. Even a small amount of testing can yield significant results and reveal big issues and problem areas early on. This means that you don’t need to spend a lot of time or money to benefit from usability testing.

On a tight budget?

Usability testing sounds like a good idea, but you're probably wondering if any affordable options exist. The answer is yes. Plenty of free or cheap tools and services are available to help you test and optimize your site. Here’s our selection of some of the best and most affordable options to get started with.

1. Userfly

Userfly is an interesting new startup. The service allows you to put a little bit of JavaScript on your website and then track a lot of your visitors' actions, from mouse movements to clicks and keystrokes (except password entries, of course). This means that you can replay a user’s session exactly as it happened, and not just on a single page either, but across your entire site. You can see where the user’s mouse moved and exactly what they typed. You can start using Userfly for free, with a limit of 10 captures. The Basic plan gives you 100 captures at $10 per month, which should be plenty to get you started.

2. Feedback Army

Feedback Army is probably the fastest way to get feedback about your website (aside from asking your colleagues). This service is powered by Amazon’s Mechanical Turk engine. As the name implies, Mechanical Turk is a human-powered “engine” designed to solve tasks that can be completed in a short period of time. Feedback Army asks users questions about your site and quickly gathers feedback and impressions so that you can improve the user experience. The cost is relatively cheap: $10 buys you 10 responses. However, don’t expect detailed reviews. Also, it is important to construct your questions carefully to receive the highest quality and most effective feedback.

3. Five Second Test

Five Second Test is a free usability testing service that offers three different ways of testing: "Classic," "Compare," and "Sentiment." The Classic test shows and then hides a screenshot of your page and asks users to recall elements that they remember. The Compare test shows two screenshots and asks users which they prefer. The Sentiment test shows one page and asks users to pick their favorite and least favorite elements. As you can probably guess from the name, testers have only 5 seconds to provide feedback after seeing a question. Also, each test can be marked as public or invitation-only, which is helpful if you need to limit exposure.

4. UserTesting

UserTesting offers a more traditional approach to usability testing. Give UserTesting your website’s demographic, and the service will select the right users to browse your site. In return, you'll receive a video of the users’ screens as they navigate your site, along with a running audio commentary of their responses. You will also get a written report detailing the areas and functions that the users liked and disliked and anything that may have prompted them to leave the site. All of this costs only $29 per test. Such low-cost and high-quality deliverables make UserTesting a great option for those looking to perform detailed tests of their websites, without having to resort to more expensive, comprehensive usability testing.

5. ClickTale

Similar to Userfly, ClickTale captures the actions of your website’s visitors, including clicks, scrolling, and keystrokes. Other features offered include a scrolling heat map, form analytics, and individual link analysis (e.g. how many clicks or hovers did each link get?). ClickTale has a free plan that records 400 page views per month for one domain. Some of the features in the free plan are limited; for example, the scrolling heat map is available only for your most popular page. Paid plans start at $99 a month, which is still a competitive price for the features that this service offers.

6. Google Website Optimizer

A good way to improve the performance of your website is to do A/B testing (also known as split testing). This means running two different versions of a particular page simultaneously for different users and recording how well each one converts. A more advanced version of this test is called multivariate testing, in which a multitude of variables are tested to discover the best combination. Google offers a tool to do exactly this: Google Website Optimizer. All you need to do is provide the various content elements (for example, different headlines or product pictures) and Google Website Optimizer will serve random combinations of them to your visitors while tracking how well each combination converts. Best of all, Google Website Optimizer is free to use.

7. ClickHeat

ClickHeat is an interesting little tool that generates heat maps of all the clicks made on your website. You've probably seen heat maps generated by eye-tracking studies: this is the same concept, but for tracking clicks instead. The service is free but needs to be downloaded and installed on a server, and so it has a couple of requirements, such as PHP support.

8. Chalkmark

Chalkmark is a usability testing app currently offered as a free beta. Chalkmark allows you to set up a series of tests; for example, a user could be shown your landing page and be asked to perform a task, such as find the sign-up page. The location(s) that the user clicks on are tracked. These targeted tests allow you to find out how easy certain tasks on your website are to perform and whether the navigation and information you provide are clear. While using Chalkmark is free, you’ll still need to find people to perform the tests. However, because they are online, the tests can be completed very quickly, and so recruiting users should be much easier than in traditional user testing.

9. Simple Mouse Tracking

Simple Mouse Tracking is another free tool to track a visitor’s mouse movements and clicks on your site. You’ll need PHP on your server to run it, although the actual pages don’t have to be PHP-based; they just require a bit of JavaScript.

10. Silverback

If you're using a Mac, then there's a great usability testing application called Silverback, which was created by the well-known design consulting firm Clearleft. It comes in handy for conducting in-person user testing. Instead of having to set up a bunch of cameras and recording equipment, you simply need to have a Mac with an iSight camera. As in a traditional user test, you sit with the user in front of the computer and ask them to perform certain tasks, all while they say their thoughts aloud. Silverback records a video of them and of what is happening on the screen. The app also has some useful note-taking functionality and lets you set chapter markers (using the Apple remote) when something interesting occurs during a session. The application costs $49.95, which is a fair price for avoiding the hassle of setting up a user-testing environment. Written exclusively for WDD by Dmitry Fadeyev. He runs a blog on usability called Usability Post. Which tools do you use to run your usability tests? Please share your experience with the services mentioned or any others that you may use.