- The Official Fee Schedule at a Glance
- What Each Fee Actually Covers
- Costs Hidden in the Eligibility Path
- Preparation Spending: What Is and Isn't Required
- Exam-Day Logistics That Carry a Price Tag
- Two-Year Cost of Ownership
- Budgeting Study Time Across the Six Domains
- Weighing the Cost Against the Return
- Frequently Asked Questions
- The initial two-year term costs $500: a $100 examination fee plus a $400 certification fee.
- A retake costs $100, and renewal at the end of each two-year term costs $400.
- $100 of the certification fee is a nonrefundable processing charge, so apply only when your documentation is ready.
- ACAC publishes no mandatory preparation course, so training spend is optional rather than a hidden requirement.
The Official Fee Schedule at a Glance
If you are budgeting for the Council-certified Microbial Consultant (CMC) credential, the good news is that the issuer's pricing is simple. The American Council for Accredited Certification (ACAC), through its CMC Certification Board, publishes a short fee list on its Fees and Payments page. There is no tiered member discount to decode, and no separate member versus non-member schedule is published.
| Fee Item | Amount (USD) | When It Applies |
|---|---|---|
| Examination fee | $100 | Initial exam attempt |
| Certification fee | $400 | Initial certification, including $100 nonrefundable processing |
| Initial total | $500 | Covers the first two-year term |
| Retake | $100 | Each additional exam attempt |
| Renewal | $400 | Every two-year renewal cycle |
Always confirm current amounts directly with ACAC before paying, since fee pages can be revised. For a broader look at how the credential's economics fit together, see our companion piece on whether the CMC certification is worth it.
What Each Fee Actually Covers
The $100 Examination Fee
This is the charge for sitting the computer-delivered written examination. The exam, delivered through Kryterion, Inc., consists of 120 multiple-choice questions, each with at least four answer options, administered closed book over three hours. The passing score is 75%, established using a Modified Angoff process. The fee buys you a seat for one attempt, nothing more.
The $400 Certification Fee
The certification fee is larger than the exam fee because it funds the credential itself: application review, board approval, and the issuance of your certification for the initial two-year term. Within this amount, $100 is a nonrefundable processing charge. That detail matters for your timing, which we cover next.
The $100 Retake Fee
If you do not reach the 75% cut score on your first attempt, each retake costs $100. That is the same price as the original exam fee, which keeps the penalty for a miss modest compared with the cost of the credential overall. Still, the cleaner path is to prepare thoroughly the first time. Our guide on how hard the CMC exam is helps you gauge readiness, and the passing score breakdown explains exactly what 75% means in practice.
The $400 Renewal Fee
Certification lasts two years. Renewal currently costs $400, so over a long career the recurring renewal charge, not the initial exam, becomes your main ongoing expense. Renewal also carries a continuing-education workload, discussed below.
Costs Hidden in the Eligibility Path
The sticker price of $500 does not include the cost of becoming eligible. ACAC's prerequisites are experience-and-education combinations, and the cost of meeting them varies enormously by candidate. The qualifying routes are:
- A related four-year postsecondary degree, or 30 qualifying college credits, plus four years of documented microbial sampling experience.
- A related two-year degree, or 15 qualifying credits, plus six years of documented experience.
- A high school diploma or GED plus eight years of consulting experience in microbial sampling.
Qualifying fields include microbiology, engineering, science, architecture, and industrial hygiene. ACAC's FAQ defines qualifying college coursework and excludes social sciences, so a candidate whose credits fall outside the accepted fields may need to take additional courses. That is a real potential cost: tuition for any coursework needed to reach the 15 or 30 credit thresholds. Candidates must also show they have designed, conducted, and interpreted sampling regimens, and the application requires four project sheets, applicable transcripts, and experience verification.
Transcript fees charged by your school and any time spent assembling project sheets are small compared with a tuition gap, but they add up. Review the full CMC requirements guide before you commit funds, so you know whether you are eligible today or need to budget for additional credits.
Key Takeaway
Audit your eligibility before you budget for the exam. A candidate who is two or three qualifying courses short faces a very different total cost than one who already meets a pathway, and the $100 nonrefundable processing charge makes premature applications expensive.
Preparation Spending: What Is and Isn't Required
ACAC states that no mandatory preparation course or minimum training-hour requirement is published, and it maintains a provider directory of optional prep courses. That means you control this line item entirely. Some candidates with deep field experience may spend very little; others will want structured instruction.
Reference Materials You May Need to Own or Access
The candidate handbook lists the references the exam draws upon. Because the exam assumes comprehensive knowledge of these sources, acquiring them is the most practical study investment. The handbook lists:
- ACGIH Bioaerosols: Assessment and Control, first edition (1999) or second edition (2024).
- AIHA Field Guide for the Determination of Biological Contaminants, second edition (2005).
- ANSI/IICRC S500-2021, fifth edition.
- S520-2015 and R520-2015, third editions, or S520-2024, fourth edition.
- OSHA Small Entity Compliance Guide for the Respiratory Protection Standard (2011).
- NIOSH Respirator Selection Logic (2004).
Note the handbook allows alternatives for the Bioaerosols and S520 references, so you do not necessarily need to buy both editions. Listing an edition does not imply an exam revision date, and it does not imply that purchased copies are included in any fee. Some of these documents are freely available from government sources (the OSHA and NIOSH items), while others are priced publications. Check availability and cost before building your budget.
Third-Party Prep and Practice Materials
Providers such as Indoor Sciences offer microbial investigator training, and several sites sell or publish practice questions. Prices and syllabus quality vary, and a provider's own course or exam is not a substitute for the ACAC examination. Keep in mind that a provider's mold-inspector exam or licensing test is a different assessment from the ACAC CMC exam, and its hours or timing do not replace the official 120-question, three-hour format. If you want a structured plan before you spend on courses, start with our CMC study guide and our overview of CMC training, and try free questions on the main practice test site to find your weak domains first.
Exam-Day Logistics That Carry a Price Tag
Scheduling goes through ACAC, and you can test at a proctored testing center or by online video proctoring. Neither route adds a published surcharge in the fee schedule, but each has practical requirements that can cost money if you are unprepared.
- Testing center: You need two government-issued IDs, including one photo ID. Travel to a center is your own expense. ACAC's current Examinations page asks for arrival 15 minutes early, while the handbook says 30; plan for the longer window to be safe.
- Online proctoring: You supply your own computer, an approved webcam, and a private location. ACAC specifies at least 2 Mbps upload and download speeds and excludes phones and tablets. If your home setup falls short, you may need to upgrade equipment or internet service.
Calculator permission is unverified, so do not assume you can bring one; confirm with ACAC when you schedule. Details on timing windows are covered in our exam dates and scheduling guide.
Timing Your Application to Avoid Wasted Spend
ACAC's current application page describes online forms, required email verifications, and unanimous board approval, with a process of roughly six months including the examination; the board meets every four to six weeks. The handbook instead describes a 90-day timeline with notarized forms and employer affidavits, and this conflict between the two issuer sources is unresolved. Notarization, if required, is a small additional cost. Since you may need to pay fees well before certification is issued, plan your cash flow across several months rather than expecting a single immediate transaction.
Two-Year Cost of Ownership
Here is a realistic view of the issuer-published costs across the first two terms, excluding optional study materials and eligibility coursework:
| Scenario | Issuer Fees (USD) | Notes |
|---|---|---|
| Pass on first attempt | $500 | $100 exam + $400 certification for the first two years |
| One retake needed | $600 | Add one $100 retake fee |
| Two retakes needed | $700 | Each further attempt adds $100 |
| First term plus first renewal | $900 | $500 initial + $400 renewal after two years, assuming a first-attempt pass |
These figures reflect only the amounts published by ACAC. They do not include reference purchases, optional courses, tuition for qualifying credits, transcript or notary charges, or equipment upgrades for online proctoring. The ACAC-reported 2025 exam pass ratio was 94%, with 16 passes from 17 attempts. That figure includes retakes and state-licensing-only candidates, and it is not a first-attempt rate, so treat it as context rather than a guarantee. See what the pass-rate data shows for the caveats.
Renewal Workload Is Part of the Cost
Renewal is more than a $400 check. ACAC's current Recertification Procedures specify 40 recertification credits (RCs) per two-year term: 10 for continued field activity and 30 for professional development, with attestation and retained evidence in case of audit, and a current photo requested. Other ACAC materials describe this differently (the handbook uses general 40-RC wording, and the program page mentions 20 professional-development hours per year), so verify the current rule when you renew. Whatever the exact wording, continuing education courses and conferences carry their own costs, which belong in a long-term budget.
Budgeting Study Time Across the Six Domains
Money is not your only budget; study hours are the other. The official domain chart (approved February 21, 2024) lists six domains and publishes no percentage weights, so no domain can be declared the most heavily tested. Spend your preparation effort across all six rather than guessing at emphasis. Below is a short allocation plan tied to those specific domains, intended to help you avoid paying for retakes.
Foundations: Domains 1 and 2
- Scientific knowledge of biological agents: build vocabulary and organism characteristics.
- Potential health effects and risks associated with exposure: connect agents to exposure outcomes.
Method: Domains 3 and 4
- Principles of Microbial Investigation: structure of an assessment and interpretation of findings.
- Principles of Microbial Sampling: design, conduct, and interpretation of sampling regimens, plus equipment and data limitations.
Response and Safety: Domains 5 and 6
- Principles of Microbial Remediation: the S500 and S520 framework and post-remediation verification.
- Health & Safety: respiratory protection using the OSHA and NIOSH references.
Note that the handbook's shorter body-of-knowledge text omits a standalone Health & Safety topic, while the formal domain chart includes it as Domain 6. Study to the formal chart. For a deeper domain-by-domain explanation, read our complete guide to all six CMC content areas, and keep our one-page review sheet handy as you approach test day.
Domain 4: Principles of Microbial Sampling
Because the credential is built around sampling consulting, this domain deserves hands-on attention beyond reading.
- How sampling regimens are designed, conducted, and interpreted.
- Equipment use and calibration, and the limits of the data collected.
- How results feed investigation conclusions and remediation decisions.
Weighing the Cost Against the Return
At $500 for the first two years and $400 per renewal, the issuer fees are modest relative to many professional credentials. Whether the return justifies the spend depends on your field. The credential is aimed at consultants who design and interpret microbial sampling regimens, which suggests relevance for professionals in industrial hygiene, building sciences, and environmental consulting. ACAC reports 288 current CMC certifications and 99 recertifications as of December 31, 2025, which indicates a relatively small credentialed community.
On earnings, no reliable salary survey specific to ACAC CMC holders has been verified, and no causal earnings premium from the credential is established. Be cautious of generic salary aggregates under similar-sounding "CMC" titles, since several unrelated credentials share the acronym. Our salary analysis and jobs overview discuss how to evaluate the credential's value without relying on unsupported numbers. If you are still confirming which credential this is, our explainers on what CMC certification is and what CMC stands for clarify that this site covers only the Council-certified Microbial Consultant.
Frequently Asked Questions
The initial cost is $500, made up of a $100 examination fee and a $400 certification fee, covering the first two-year term. Of the certification fee, $100 is a nonrefundable processing charge.
A retake costs $100 per additional attempt, according to the ACAC fee schedule. Retakes do not require you to repay the certification fee for the same application.
Renewal costs $400 and is due at the end of each two-year term. It also requires recertification credits, with attestation and retained evidence in case of audit, so factor continuing-education costs into your plan.
No. ACAC publishes no mandatory preparation course or minimum training-hour requirement. It maintains a directory of optional providers, but a provider's own mold-inspector exam is not a substitute for the ACAC CMC exam.
No separate member or non-member fee schedule is published for this credential. The fees listed on ACAC's Fees and Payments page apply as stated, so confirm current amounts with ACAC before paying.
To pressure-test your readiness before committing funds, take free questions on the CMC Exam Prep practice test site and see which of the six domains needs the most attention.