Are You Allowed to Use a Calculator on the OAR?
The short answer is No. Calculators are strictly prohibited on the Officer Aptitude Rating (OAR) exam. This policy significantly impacts how candidates must prepare for the Math Skills Test (MST). Without a calculator, your mental math speed, estimation skills, and scratch paper strategy become the deciding factors for your score.
Use the specialized OAR Score & Mental Math Pacing Calculator below to estimate your potential OAR score based on your current practice accuracy and calculate whether your mental math speed is fast enough to finish the exam on time.
OAR Score & Mental Math Pacing Estimator
Enter the percentage of math questions you answer correctly (0-100%).
Enter your average percentage on reading practice sets.
Enter your average percentage on mechanical practice sets.
Seconds it takes to solve one problem using only scratch paper (no calculator).
Estimated OAR Score (20-80 Scale)
Average Competitive Score
| Accuracy Level | Math Raw | Est. OAR Score | Selection Probability |
|---|
What is “Are You Allowed to Use a Calculator on the OAR”?
The query “are you allowed to use a calculator on the OAR” is one of the most common questions asked by prospective Navy, Marine Corps, and Coast Guard officers preparing for the Aviation Selection Test Battery (ASTB-E). The Officer Aptitude Rating (OAR) is a subset of this exam, consisting of three sections: Math Skills (MST), Reading Comprehension (RCT), and Mechanical Comprehension (MCT).
The definitive answer is that no calculators of any kind are permitted. This includes physical scientific calculators, graphing calculators, and software calculators. Candidates are provided with scratch paper and pencils only. This policy is strictly enforced to test a candidate’s innate numerical reasoning, estimation capabilities, and ability to handle pressure—skills deemed essential for military officers, particularly in aviation and engineering roles.
Many candidates who rely heavily on technology for basic arithmetic find the OAR challenging not because of the complexity of the math (which is largely Algebra I, Geometry, and basic probability), but because of the mental fatigue and time constraints associated with manual calculation.
OAR Scoring Formula and Mental Math Explanation
Since you cannot use a calculator, understanding how the OAR is scored helps prioritize which mental math shortcuts to learn. The OAR uses a standard score scale ranging from 20 to 80, with a mean of 50 and a standard deviation of 10.
The exam is computer-adaptive, meaning the difficulty of the next question depends on whether you answered the previous one correctly. Therefore, accuracy on early/easier questions (which require simple mental math) is crucial for reaching higher difficulty tiers where the scoring weight is heavier.
Key Variables in OAR Estimation
| Variable | Meaning | Unit | Target Range |
|---|---|---|---|
| MST Accuracy | Percentage of math questions answered correctly. | Percentage (%) | 75% – 90% |
| Pacing (Time/Q) | Time spent per question using mental math. | Seconds | 45s – 90s |
| MCT & RCT | Mechanical & Reading scores (support the total OAR). | Percentage (%) | 70% – 90% |
| Time Limit | Total time allowed for the Math Skills Test. | Minutes | 40 mins (approx 30 Qs) |
Practical Examples: Calculating Without a Calculator
To succeed without a calculator, you must master estimation. Here are two examples of how to approach OAR-style problems manually.
Example 1: The Efficient Candidate
Scenario: Candidate A encounters the problem: “A plane travels 450 miles in 1.5 hours. What is its speed?”
- Without Calculator: Convert 1.5 to 3/2. Formula is Distance / Time.
- Calculation: 450 ÷ (3/2) = 450 × (2/3). 450/3 is 150. 150 × 2 is 300.
- Time Taken: 20 seconds.
- Result: Correct answer, minimal brain drain.
Example 2: The Dependent Candidate
Scenario: Candidate B tries to do long division for 450 ÷ 1.5 on scratch paper because they are used to typing it into a calculator.
- Process: Sets up long division, moves decimals (4500 ÷ 15), subtracts manually.
- Time Taken: 90 seconds.
- Result: Correct answer, but lost valuable time for harder geometry problems later.
How to Use This OAR Calculator
This tool is designed to benchmark your readiness given the “no calculator” constraint. Follow these steps:
- Take a timed practice test: Attempt a full Math Skills Test without a calculator.
- Enter your Accuracy: Input your percentage score for Math, Reading, and Mechanical sections.
- Enter your Pacing: Calculate the average time you spent per math question (e.g., if you finished 30 questions in 40 minutes, that’s 80 seconds/question).
- Analyze Results:
- Estimated Score: Your likely OAR score range (20-80).
- Efficiency: If your time per question is >80s, the tool will flag “Time Risk,” indicating you might run out of time on the real test.
Key Factors That Affect OAR Results
Since you are not allowed to use a calculator on the OAR, several non-mathematical factors influence your score significantly:
- Mental Math Stamina: The OAR is long. Doing 30+ math problems manually, followed by mechanical physics problems, drains glucose. Practice building endurance.
- Scratch Paper Organization: A messy scratch paper leads to transcription errors. Keep your manual calculations organized in grids.
- Fraction Conversion Speed: Converting decimals to fractions (e.g., 0.125 to 1/8) often makes manual calculation 5x faster than long division.
- Approximation: In physics (Mechanical Comp) and complex math, the answers are often far apart. Approximating $\pi$ as 3 or $g$ as 10 is usually sufficient and permitted by the logic of the test.
- Panic Management: Getting stuck on a calculation without a backup device induces panic. Knowing when to guess and move on is a critical “no calculator” skill.
- Time Management: The math section has a strict time limit (approx 40 minutes). Averaging under 1 minute per question is ideal to leave buffer time for checking work.
Frequently Asked Questions (FAQ)
Can I use a slide rule on the OAR?
No. Slide rules, abacuses, and any other mechanical calculation aids are prohibited. Only the provided pencil and scratch paper are allowed.
What happens if I get caught using a calculator?
Your test will be immediately invalidated, you will be removed from the testing center, and you may be permanently barred from applying to officer programs.
Is the on-screen computer calculator available?
No. Unlike the GRE or some GMAT sections, the ASTB-E/OAR software interface does not provide an on-screen calculator.
How much scratch paper do I get?
You are typically given a few sheets to start and can raise your hand for more. However, waiting for the proctor can waste time, so use space efficiently.
Are formulas provided on the test?
Generally, no. You are expected to know basic geometry formulas (area of circle, triangle, volume of cylinder) and physics formulas (velocity, leverage, pulleys) by heart.
What is a good OAR score?
Scores range from 20 to 80. A score of 45-50 is generally considered average/passing for many programs. Competitive scores for aviation usually start around 50-55.
Does the “No Calculator” rule apply to the whole ASTB?
Yes. The entire ASTB-E, including the aviation nautical information and performance-based measures, is taken without a calculator.
How can I practice without a calculator?
Stop using one immediately in your daily life. Calculate tips, grocery totals, and gas mileage in your head. Use apps specifically designed for “mental math training.”
Related Tools and Internal Resources
Prepare effectively for your officer application with these related guides:
- Comprehensive OAR Study Guide – Full breakdown of all three sections.
- Top 10 Mental Math Tricks for the ASTB – Speed up your calculation time.
- Mechanical Comprehension Practice Test – Test your physics knowledge.
- Navy Officer Requirements Checklist – See if you qualify.
- ASTB vs ASVAB Differences – Understanding the officer vs enlisted tests.
- Full ASTB-E Overview – What to expect beyond the OAR.