ASVAB Technical Subtests: GS, EI, AI, SI, MC and AO
Six ASVAB subtests sit outside the AFQT entirely. They have no bearing on whether you can enlist — and complete control over what you can do once you have. If you already know which job you want, these are the subtests that decide whether you get it.
Test Ninjas Research · Updated September 11, 2026
The six technical subtests
Subtest
Computer version
Paper version
General Science (GS)
16 items · 8 min
25 items · 11 min
Electronics Information (EI)
16 items · 8 min
20 items · 9 min
Auto Information (AI)
11 items · 7 min
combined as AS
Shop Information (SI)
11 items · 6 min
combined as AS
Mechanical Comprehension (MC)
16 items · 20 min
25 items · 19 min
Assembling Objects (AO)
16 items · 16 min
25 items · 15 min
Where it counts
None of these six affect the AFQT. They determine which jobs you qualify for, not whether you can enlist.
What it asks of you
General Science — physical and biological sciences at school level
Electronics Information — circuits, current, components and electrical principles
Auto Information — automotive systems and how they fail
Shop Information — tools, materials and shop practice
Mechanical Comprehension — levers, pulleys, gears and mechanical advantage
Assembling Objects — spatial reasoning, the only ASVAB subtest of its kind
Auto and Shop are two separate subtests on the computer version and one on paper
Every one of these feeds at least one service composite
How to approach it
Work backwards from the job
There is no reason to prepare all six evenly. Find the composite your target job is scored on, and prepare the subtests that feed it. A Navy nuclear-field candidate needs Mechanical Comprehension; an Army Skilled Technical candidate needs General Science. Preparing the others is effort spent on doors you were not trying to open.
Auto and Shop split on the computer version
The paper test administers Auto and Shop Information as one 25-item subtest and reports one AS score. The computer version splits them into separate Auto Information and Shop Information subtests, then recombines them into a single AS composite for the line scores. This is the whole reason the computer version has ten subtests and the paper version has nine.
Assembling Objects is the odd one out
It is spatial rather than knowledge-based — you decide how parts fit together — so it is the one technical subtest that does not reward reading up beforehand. It rewards practice with the item format instead. It feeds a small number of composites, notably the Navy operations and mechanical composites.
These subtests decide which jobs you qualify for, not whether you can enlist. Work out which composites they feed with the ASVAB line score calculator.
West Point, the Naval Academy, the Air Force Academy and ROTC scholarships all take an SAT or ACT score, not the ASVAB. Our SAT course covers Reading & Writing and Math in full, with adaptive practice tests and instant scoring.
No. The AFQT comes only from Arithmetic Reasoning, Mathematics Knowledge, Word Knowledge and Paragraph Comprehension. You could score at the floor on all six technical subtests and still qualify to enlist — you would simply have very few jobs open to you.
Auto and Shop Information is administered as a single subtest on the paper version and as two separate subtests, Auto Information and Shop Information, on the computer version. Both report a single combined AS score.
Only the ones feeding the composite for the job you want. Each service scores jobs on different combinations, so identify the composite first — the line score calculator shows which subtests enter each one — and prepare accordingly.
A spatial reasoning subtest in which you determine how a set of parts will look once connected or assembled. It is the only ASVAB subtest measuring spatial ability, and it feeds a limited number of service composites.