ACT English Practice TestsLearning Express Library Tests 2 Full ACT Practice Tests. LearningExpressLibrary is easy to use and offers great resources. It takes only a moment to register, and then you click "ACT Practice Tests" under "College Enterance Exams." You can then take tests section by section. After taking their timed online tests, you get a score report categorized by topics. Answers can be reviewed along with detailed explanations for all problems. Your main page keeps track of your quiz attempts and progress. Under ACT Preparation Course Series there is are online courses for every subject, my personal favorite of the bunch. It is very organized and detailed, so if that fits your learning style, use it. The questions are some of the best available in terms of quality and quantity.
Peterson's ACT Practice Test Registration required, 1 full ACT. This ACT is entirely online, and it includes a timer and pause features. The test takes under a minute to load, and has a simple interface. Since it displays questions individually, each question can take a second or two to display, which can be annoying when fighting the clock and you have slow internet. After finishing the sections, the test is automatically graded, and you can go back and review the explanations for the questions you missed, again one at a time. You can view two sample essays and assign yourself a score. Peterson's free ACT is a good resource if you do not mind clicking through the test question by question.
Kaplan Free ACT Resources 1 full ACT test and customized quizzes with 370 questions. This test requires a little bit of planning and registration before you can take it. You want to get the "ACT Course Demo" to get the complete ACT test, and the "Free ACT Quizbank" to take customized ACT quizzes. The test is a PDF download. You will have to decide whether to print the document or view the test on the computer and write down answers by hand. The questions look and feel like a real ACT, so it's good practice. Once done, you can enter your scores online to grade the test ONLY if your account has been activated more than 24 - 48 hours. You must plan ahead to take this test! Along with the answers come explanations, which are very detailed. Unique to Kaplan is an "essay grader" that asks you several questions about your essay and gives you an approximate score. I would not trust it too much, but it can give you a decent idea. This is a great resource, especially if you register 2 days before you take the test, but the 2 day wait for online scoring and analysis is a serious drawback. The Quizbank is also a great resource since you can choose what questions to put on your quiz, and you can make it as long or as short as you like. There is a timed mode, where explanations are avaliable at the end, and a tutor mode, where explanations appear after each question. Both the full test and quizzes are great, and the extra registration and waiting are definitely worth it.
Princeton Review Free Practice ACT 1 full ACT Practice test with 1 Math quiz. Registration only takes a moment, and if you're worried about spam, a valid email isn't required. You have to register to take their free ACT course. After registering, you can use this link again to make sure you take the right test. A seperate window will pop up with a fancy navigation screen; take the practice test under "Your Course" or the sample math quiz under "Practice." The test can be paused, and there is an essay. The site grades the test and estimates your score. Questions can be reviewed by going to a section and clicking on the question. For answer explanations, click the question-mark icon to the right. Princeton Review has a great practice test, but the site can be hard to use as you have to pay for almost anything more.
Official ACT Prep Test 1 full ACT Practice test is included on the ACT website, so make good use of this! There are also many pages of tips and suggestions. No explanations are given, however. Although this is the 2008-2009 version currently, if you want more editions, the 2005-2006 and 2006-2007 versions are also online. Remember these were made in exactly the same style as the test you will soon take, so make use of them!
Jefferson County Schools ACT Prep This school district posted some older 2006 ACT resources that we can all now enjoy. They aren't complete ACT tests, but they are still written by the ACT company. The abbreviated ACT test can be found here and a PDF called "Practice Questions Matched to Standards" can be found here. Definitely take these tests to get used to the ACT's style.
Try SAT Practice Tests for even more free test prep. It's pretty similar in many parts.