The U.S. federal standard, explained
For Clerk-Typist (GS-2/4), Office Automation Clerk/Assistant, and positions titled (Typing) or (Office Automation), OPM's qualification standard sets 40 words per minute. Its footnote bases this on a 5-minute sample with 3 or fewer errors. Applicants can meet it by passing a performance test, showing an authorized proficiency certificate, or self-certifying, and agencies may test self-certified applicants (OPM).
State and local tests vary
State and city civil service exams set their own formats and speeds. Check the exam announcement for the length, scoring and whether errors are counted per word or per keystroke.
How to practice for a 5-minute test
Pick 5 minutes above. Aim for 3 errors or fewer, then raise speed. A RiteType certificate is a practice record; it isn't an OPM-authorized proficiency certificate.