Iowa written test scoring: 20 of 25

Iowa Administrative Code 761-604.20(1) provides that a knowledge test may be revised at any time and that each test states its own minimum passing score. That single sentence is the reason no official Iowa source names a question count or a percentage for the operator knowledge test: the rule deliberately leaves both to the version of the exam being administered. Two further facts come from the same rule and are firm. Subsection (4) makes a passing score valid for 180 days, so the written test can be cleared months before the rest of the process. Subsection (5) leaves retesting after a failure to the examiner's discretion instead of fixing a statewide waiting period, so how soon you can try again is a conversation at the station rather than a published rule.

Iowa lets the knowledge test happen outside any licensing office. A parent or guardian who holds a valid Iowa license can proctor the permit knowledge test at home, starting 30 days before the applicant's 14th birthday, and participating schools can administer it on site. The route runs on an approval rather than a walk in: the parent submits Iowa DOT form 431508, Application to Proctor Knowledge Exam, processing takes 7 to 14 days, and the emailed test link then expires after 72 hours, so the sitting has to be arranged inside that window. The closest Iowa DOT comes to publishing a format is its own practice test, which generates 25 questions at random from a bank that includes questions from the real knowledge test and sets 80 percent as the mark, and the state is explicit that this describes the practice version.