OHC Passing Score 2026: Exactly What You Need to Pass

The Number: 70% Minimum

If you are searching for the passing score on the Occupational Hearing Conservationist (OHC) exam, the answer is straightforward: 70% is the minimum. This applies to the written exam administered through the Council for Accreditation in Occupational Hearing Conservation (CAOHC) for initial certification, which awards the COHC designation.

This article covers the initial Occupational Hearing Conservationist certification only. It does not address Course Director or Professional Supervisor/Audiologist (CPS/A) certification, which are separate credential paths with their own requirements. If you are still orienting yourself, our explainer on what OHC certification is covers the basics before you dig into scoring.

The 70% figure is the only scoring threshold published in the sources we reviewed. CAOHC does not, in the handbook or the online exam guide, publish a scaled-score conversion, a curve, or per-domain minimums. That absence matters, and we will come back to it when we discuss the exam blueprint.

What 70% Means in Practice

A 70% minimum means you can miss roughly three of every ten questions and still pass. But translating that to an exact number of required correct answers is not something we can do honestly, because the official materials disagree on how many questions appear on the initial exam (more on that below). Anyone who gives you a precise "you must answer X questions correctly" figure without acknowledging that conflict is guessing.

What you can say with confidence:

• The standard is percentage-based. Your result is measured against 70%, not against other candidates. There is no published evidence of grading on a curve.
• Every question is a single-best-answer item. There are four options per question, and one is the best answer. You are not selecting multiple correct responses.
• Unanswered questions cannot help you. Because the timer cannot be paused, pacing matters. A blank is worth the same as a wrong answer, so make a considered pick on every item before time runs out.

Exam Format, Timer, and Language

Understanding the mechanics of the exam helps you convert knowledge into points. Here is what the CAOHC sources establish for the initial written exam:

Note the distinction that trips up some candidates: the 75-minute exam timer is entirely separate from the 20-hour minimum course length. The 20 hours describes the approved training course you must complete; the 75 minutes describes how long you have to sit the written exam. They are not interchangeable, and one does not substitute for the other.

Using the flag feature wisely

Because you can flag questions and return to them, the efficient approach is a two-pass strategy. On the first pass, answer everything you know immediately and flag items that need calculation or careful recall. On the second pass, spend your remaining minutes on the flagged items. With an unpausable timer, never let a single hard item consume time that easier questions deserve.

Administration of the exam runs through the CAOHC Learning Center, with the Course Director or an approved proctor overseeing delivery. Tuition and course registration are handled by your Course Director rather than directly through CAOHC, so questions about logistics and fees should go to them. For a fuller picture of costs, see our breakdown of OHC certification cost.

The Question-Count Discrepancy

One of the most useful things to know about the OHC passing score is what we cannot tell you: exactly how many questions are on the initial exam. CAOHC's own published materials conflict. The OHC Handbook references one figure, while the online exam guide states a different one. We have seen 55 in the handbook and 50 in the online guide.

We are deliberately not picking a winner, and we are not assuming that the gap reflects scored versus unscored questions. CAOHC has not reconciled the discrepancy in the sources we reviewed, and speculating would put an invented explanation in front of you. Instead:

• Confirm the current count with your Course Director before exam day.
• Read the official online exam guide and the handbook yourself.
• Build your study plan around the 70% threshold and the 75-minute timer, which are consistent across sources.

Eleven Blueprint Headings, No Published Weights

The OHC Handbook and Instructions (revised February 2023) lays out an exam blueprint with eleven headings. Critically, the percentages are omitted. That means there is no officially supported "highest-weight domain" you can safely over-index on. Any source claiming that one specific domain makes up a particular share of the exam is not drawing from CAOHC's published blueprint.

The eleven areas are:

1. Hearing Conservation (Overall)
2. Anatomy, Physiology and Diseases of the Ear
3. Hearing and the Physics of Sound and Performing and Explaining a Hearing Test
4. Federal and State Regulations Related to Occupational Noise-Induced Hearing Loss
5. Audiometer and Testing Environment
6. Audiometric Techniques and Testing
7. Audiometric Review and Evaluation
8. Noise Measurement and Control
9. Hearing Protection Device (HPD) Fitting
10. Counseling and Training
11. Recordkeeping and the Hearing Conservation Team

For a deeper look at what each heading covers, see our complete guide to all 11 OHC content areas.

What the lack of weights means for your 70%

Without published weights, the safest strategy for clearing 70% is breadth. Because you cannot know which areas contribute most to your score, a weak spot in any single heading is a risk. Here are a few clusters worth recognizing, framed as topics a candidate should be able to handle rather than as weighted predictions:

Because the exam is built from a blueprint rather than a published weighting, candidates who spread preparation evenly tend to be safer than those who bet on a favorite topic. Our OHC study guide walks through a balanced approach.

Passing the Exam Is Only One of Three Gates

Scoring 70% on the written exam does not, by itself, make you a certified Occupational Hearing Conservationist. CAOHC certification requires three things together:

1. A minimum 20-hour approved course.
2. Satisfactory audiometric and hearing-protection-fitting practicums.
3. The written exam, passed at the 70% minimum.

There are no course-enrollment prerequisites, which means you can enroll in an approved course without first holding a particular degree or prior credential. That makes the course the real entry point, and the practicums are where you demonstrate hands-on competence that a multiple-choice exam cannot measure. Details on eligibility are in our OHC requirements guide.

Attempts, Retakes, and the 30-Day Window

CAOHC allows a maximum of three attempts at the written exam. If you do not reach 70% on a given attempt, retakes are arranged with your Course Director within 30 days of the preceding attempt. Be aware that proctoring fees may apply to retakes, so ask your Course Director about costs up front.

Practical implications of this structure:

• The 30-day window is a planning constraint. If you do not pass, you cannot take your time deciding when to try again; coordinate with your Course Director promptly.
• Three attempts is a ceiling, not a target. Use the first attempt as a real attempt, not a trial run, since you have a finite number of tries.
• Diagnose before you retake. After a miss, map your weak spots to the eleven blueprint headings and spend the intervening weeks on those, rather than rereading everything.

If you are weighing how demanding the exam really is, our guide on how hard the OHC exam is offers context, and our page on the OHC pass rate explains what published data does and does not exist.

Recertification: A Different Exam, A Different Clock

Your certification is valid for five years from course completion. Renewal is not a repeat of the initial process. It requires:

• A minimum 8-hour refresher course.
• Both practicums (audiometric and hearing-protection fitting).
• A separate 30-question, 45-minute recertification exam.

The recertification exam is a distinct instrument from the initial written exam, with its own question count and time limit. Do not assume that preparing for the initial exam's 75-minute format maps directly onto the shorter recertification test. If you need more time, you can request an extension, but CAOHC asks that you do so at least 30 days before your certification expires.

Sequencing Your Preparation Around the Blueprint

Since no domain is officially weighted, a sensible schedule orders topics by dependency rather than by guessed importance. The testing-chain headings build on sound physics and ear anatomy, so it helps to learn those foundations first. Here is one way to sequence it, anchored to the actual headings:

Adjust the pacing to your course schedule; the point is the ordering logic, not the number of weeks. Our OHC cheat sheet condenses the must-know facts for a final review pass, and you can test your readiness against the 70% bar with full-length questions on the main practice test site.

Frequently Asked Questions