Can your website handle the stress? Slow websites means lost customers and revenues. Be proactive and find out the performance limits of your website before you learn the hard way. Load Impact is an online load testing service that lets you load test your website with just a few mouse clicks.

Load Impact generates simulated user traffic to your site – for example it might simulate that 50 users are trying to load your web pages at the same time. While simulating the traffic from these 50 users, it also records how fast pages are loaded from your server. This lets you know how fast your site is (as experienced by a user) when it is being accessed by 50 users at the same time.

Load Impact runs on the servers, over the Internet. You will always have access to your test configurations and your test results. You will never need to install or maintain any special software or servers for your testing. It is completely free to run simple load tests with up to 50 concurrent, simulated users.

Source: http://loadimpact.com/