Students applying to study at a university in a country that does not use their native language typically have to sit a formal language assessment exam; This exam is now most commonly done electronically. This can be challenging for students if they do not have previous experience with online tools. While previous studies have shown that practice of some skills exam, such as writing tasks, help improve students’ performance, while other test skills has to be investigated. Still, there are few scientific and published studies on the usability and the effect of the design of test elements and their effect on test accuracy and effectiveness. The purpose of this study is to investigate factors of online English as a foreign language (EFL) tests and how they can adversely affect students' performance during the test. To meet this aim, we investigated the correlation between test structure and some test-taker characteristics. The study's significance is considered a guideline for test designers to improve the test design, which should lead to a more accurate assessment of the student’s performance. This research was conducted using an online survey of new University entrance students. The key findings of this study are that less confidence during the test may result in an artificially reduced test score, with a potentially significant impact on a student’s career or need to retake repeatedly. Moreover, other facts have been measured about an English online test such as first language, subject area and previous training on such examination. These contribute to challenges during the exam, which were raised in participants' responses on having difficulty interacting with the test.