ASVAB Mechanical Comprehension: format, principles and how to prepare
Last checked October 14, 2026 · Sources: Department of Defense What to Expect page, Fact Sheet and sample questions; Army and Air Force ASVAB pages
ASVAB Mechanical Comprehension (MC) tests your understanding of mechanical and physical principles: levers, pulleys, gears, forces and the properties of materials. It isn’t part of the AFQT, but it appears in more Army line scores than any subtest outside the AFQT, including the Combat score for infantry jobs.
What Mechanical Comprehension tests
The Department of Defense describes Mechanical Comprehension as knowledge of mechanical and physical principles, in the Science and Technical domain. The Air Force lists the content as the principles of mechanical devices, structural support and the properties of materials. Questions often show a simple machine or setup in a picture and ask what happens, which way something turns, or how much force is needed.
Format and timing
| Computer (CAT-ASVAB) | Paper (P&P-ASVAB) | |
|---|---|---|
| Scored questions | 15 | 25 |
| Time limit | 22 minutes (42 with tryouts) | 19 minutes |
| Average time per question | About 1.5 minutes | About 46 seconds |
| Go back and change answers | No | Yes, within this subtest |
Source: officialasvab.com What to Expect page and Fact Sheet, checked October 14, 2026. Time per question is our calculation.
Mechanical Comprehension comes near the end of the test, right after Auto and Shop and just before Assembling Objects. The computer version allows about a minute and a half per question, enough to sketch a quick diagram if you need one. On paper you have well under a minute, so the principles below need to be familiar before test day.
Where Mechanical Comprehension counts
| Branch | Job scores that use Mechanical Comprehension |
|---|---|
| Army | Combat, Field Artillery, Mechanical Maintenance, Operators and Food, Surveillance and Communication, and Skilled Technical line scores |
| Air Force | Mechanical MAGE score |
Sources: goarmy.com and airforce.com ASVAB pages, checked October 14, 2026.
That is six of the Army’s ten line scores. For anyone targeting combat arms, artillery or mechanical jobs, MC deserves as much study time as the AFQT subtests. See our Army and Air Force score guides.
Principles to know
Most questions come back to a handful of ideas. Simple machines trade force for distance: a lever, pulley or ramp lets you use less force, but you move it over a longer distance, so the work stays the same. On a lever, effort times its distance from the pivot (fulcrum) equals load times its distance from the fulcrum. Gears that mesh turn in opposite directions, and a small gear driving a larger one turns the larger one more slowly but with more turning force. A single movable pulley ideally halves the force needed to lift a load. Liquids pass pressure equally in all directions, which is how hydraulic jacks and brakes multiply force.
Material properties matter too. Some materials are strong in tension (pulling) and others in compression (pushing). Heat makes most materials expand. A wider base makes a structure more stable, and a beam supported at both ends sags most in the middle.
Worked examples
These are our own practice problems, not real ASVAB questions.
- Lever. A 20-pound load sits 2 feet from the fulcrum. How much force is needed 4 feet from the fulcrum on the other side? 20 × 2 = force × 4, so the force is 10 pounds.
- Gears. Gear A turns clockwise and meshes with gear B. Which way does gear B turn? Counterclockwise. A third gear meshing with B would turn clockwise again.
- Gear speed. A 10-tooth gear drives a 20-tooth gear. When the small gear makes one full turn, the large gear makes half a turn.
- Pulley. Ignoring friction, how much force lifts a 100-pound load with a single movable pulley? About 50 pounds, but you pull twice as much rope.
- Ramp. Which takes less force to push a box up to the same height: a 4-foot ramp or a 10-foot ramp? The 10-foot ramp, over a longer distance.
How to prepare for Mechanical Comprehension
Try the Department of Defense's free Mechanical Comprehension sample questions to see the picture-based style.
Learn the lever equation and the rules for gears, pulleys and ramps until you can apply them without thinking.
When a question shows a setup, sketch it and mark the forces, the pivot and the direction of motion.
Turning a wrench, lifting with a bar or riding a bike with gears all show these principles at work; noticing them makes questions familiar.
Finish with timed sets of 15 questions in 22 minutes.
Our free ASVAB resources page lists no-cost practice.
Mistakes that cost Mechanical Comprehension points
- Forgetting that meshing gears reverse direction.
- Measuring lever distances from the wrong point instead of the fulcrum.
- Assuming a machine reduces the work done, rather than trading force for distance.
- Skipping it because it isn’t in the AFQT, then missing a combat job’s line score.
Common questions about ASVAB Mechanical Comprehension
How many questions are on ASVAB Mechanical Comprehension?
On the computer version, 15 scored questions in 22 minutes, or 42 minutes if tryout questions are added. On the paper version, 25 questions in 19 minutes.
Does Mechanical Comprehension count toward the AFQT?
No. It feeds job scores, not the AFQT.
What topics are on Mechanical Comprehension?
Levers, pulleys, gears, ramps, hydraulics and the properties of materials, based on the Air Force’s description of mechanical devices, structural support and materials.
Does Mechanical Comprehension matter for infantry?
Yes, in the Army it is part of the Combat line score used for infantry, along with Verbal Expression and Auto and Shop.
Do I need advanced physics for Mechanical Comprehension?
Only basic arithmetic, such as the lever equation. The focus is understanding how things move and carry force.
See also our Auto and Shop and Electronics Information guides, or go back to the ASVAB overview. MockTestPrep is independent and is not affiliated with the Department of Defense or any service branch.