Free · No sign-up
OAR practice tools
Free practice for Navy officer candidates preparing for the OAR. No sign-up, and everything runs in your browser.
Practice tests & drills
Check where you stand on each OAR subtest, with an explanation for every answer.
Free OAR practice test
Take a free 15-question OAR practice test covering math, reading and mechanical comprehension. Instant scoring and an explanation for every answer.
Open toolOAR math practice test
Free OAR Math Skills practice test: 15 word problems, algebra, geometry and probability questions with worked answers. No calculator, like the real test.
Open toolMechanical comprehension practice test
Free OAR mechanical comprehension practice test: levers, gears, pulleys, hydraulics, fluids and circuits. 15 questions with answers explained.
Open toolReading comprehension practice test
Free OAR reading comprehension practice test: 15 short passages with main-idea, detail and inference questions, each answer explained.
Open toolNo-calculator math drill
Timed no-calculator math drill for the OAR: arithmetic, fractions, percents, exponents and order of operations, with instant feedback.
Open tool
Mechanical comprehension calculators
The formulas behind levers, gears, pulleys, hydraulics and circuits, with worked examples.
Gear ratio calculator
Find the speed, gear ratio, torque change and direction of a driven gear from tooth counts and driver rpm, including idler gears. Worked OAR-style examples.
Open toolLever calculator
Solve any balanced lever problem: effort force, load or arm length from the other three, plus mechanical advantage. With the three lever classes explained.
Open toolMechanical advantage calculator
Calculate mechanical advantage and effort force for pulley systems, inclined planes (ramps) and wheels and axles, the simple machines on the OAR.
Open toolHydraulic press calculator
Find a hydraulic press’s output force, pressure, mechanical advantage and piston travel from the input force and piston areas, using Pascal’s principle.
Open toolOhm’s law & resistor calculator
Solve for voltage, current or resistance with Ohm’s law, get power, and add resistors in series and parallel. Simple circuits for the OAR.
Open tool
Study references & planning
Formulas and words to know cold, and when you can sit the test again.
OAR formula sheet
The key OAR formulas on one page: arithmetic, algebra, geometry and statistics, plus levers, gears, pulleys, pressure, energy and circuits.
Open toolOAR vocabulary list
A free OAR vocabulary list: 28 words from the OAR Prep verbal flashcards, with definitions, example sentences and a hide-the-meanings self-test.
Open toolASTB-E retest date calculator
When can you retake the OAR? Enter your last ASTB-E test date and attempts used to get your earliest retest date and how many attempts you have left.
Open tool