CTW Passing Score 2026: Exactly What You Need to Pass

Two Components, Two Passing Thresholds

The ISA Certified Tree Climber credential (formerly called ISA Certified Tree Worker Climber Specialist, renamed in 2023) is not decided by a single score. You earn it by passing two separate components, each with its own cutoff:

Passing both is required unless an approved exception applies (the competition-based waiver covered below is the main one). A strong written score cannot rescue a failed climb, and a flawless climb cannot compensate for a failed written exam. If you want the full picture of eligibility before you worry about scoring, start with our guide to CTW requirements, eligibility, and prerequisites.

The Written Exam: 65 Questions, 80% to Pass

The written component is a closed-book, computer-based test delivered at Pearson VUE physical testing centers (ISA Certification Partners can also arrange paper-based written exams). Each question has four options and exactly one correct answer. Phones and reference materials are prohibited, and breaks count against your 90 minutes.

How the 65 and the 15 fit together

This is the most commonly garbled detail in third-party prep content. The exam contains 65 questions in total. Of those, 15 are unscored pretest items that ISA uses to evaluate future questions. That leaves 50 scored questions. It is not 65 scored questions plus 15 extras, which is how at least one competing practice site describes it.

You will not be told which items are the pretest questions, so every question deserves your full effort. The 80% requirement applies to the scored portion, which means that on a 50-question basis you are aiming for roughly 40 correct. Treat that as a planning figure: ISA's published criterion is the 80% threshold itself, so don't rely on guesses about how any single item is weighted.

The Skills Assessment: 70% and 27 of 38 Points

The outdoor skills assessment is where many candidates feel the most pressure, because it is physical, timed, and evaluated by a person watching you work. The pass line is at least 70%, which in points translates to a minimum of 27 of 38. The 2024 Skills Test Evaluation Form defines the structure of what is scored.

The pieces of the assessment

• Equipment inspection: You demonstrate that your climbing gear is compliant and in serviceable condition. Compliant climbing equipment is required for the practical component.
• Six knot demonstrations: Each knot is allotted one minute. These are distinct from the timed climb.
• Work climb and stations: Movement through the tree, work positioning, and descent, including tasks tied to MRS (moving rope system) and SRS (stationary rope system) techniques.

The climb clock

The timing rules are specific and easy to misread, so here they are precisely:

• The clock starts on your first rope throw.
• The full-credit target is 30 minutes. Exceeding it incurs a three-point timing deduction.
• The maximum is 45 minutes. Exceeding 45 minutes fails the task.
• Preparatory equipment inspection and the knot demonstrations are separate from the timed climb.

Do the math against a 38-point scale and the three-point deduction matters: it is roughly 8% of the total, and your cushion above the 27-point floor is only 11 points. A slow but otherwise clean climb can still pass; a slow climb with several small errors may not. Do not confuse this 45-minute climb limit with the written exam's 90 minutes. The numeric exam line describes the written component only.

Critical Requirements Can Override Your Points

Here is the part candidates most often underestimate. Reaching 27 of 38 is necessary but not sufficient. The evaluation form defines critical failures, and you must satisfy all critical requirements to pass. In practical terms, a safety-critical error can fail you even if your point total looks healthy.

This mirrors how the credential works in the field. Climbing is a safety-first trade, and the assessment is designed so that a candidate who cuts a corner on a life-safety item cannot offset it with polish elsewhere. Study the 2024 Skills Test Evaluation Form directly rather than relying on a summary, and note which items are flagged critical. Then practice those items until they are automatic.

A knot quiz or practice test cannot measure any of this. A written score tells you nothing about physical competency, which is why the credential requires an evaluator-observed assessment. For deeper context on how demanding the whole process is, see how hard the CTW exam really is.

Passing Score vs. Pass Rate

These are two different things, and mixing them up is how bad statistics spread. The passing score is the cutoff you must reach: 80% written, 70% skills with at least 27 of 38 points, and all critical requirements met. The pass rate is the share of all candidates who pass.

ISA has not publicly disclosed an aggregate pass rate in the issuer sources reviewed. Some third-party pages quote failure percentages, but those figures are unsupported and cannot be traced to ISA. We do not repeat them here. If you want to understand what the available evidence does and does not show, read our breakdown of the CTW pass rate.

Where the Written Points Live: Five Weighted Domains

The written exam follows the five-domain ISA Certified Tree Climber Examination Outline (2024 file, based on the 2022 job-task analysis). Weights total 100%, and they tell you where to spend your preparation hours.

*Illustrative arithmetic applying each weight to the 50 scored items. Actual distribution on any single exam form can vary slightly.

Two observations follow. First, Safety, Tree Climbing and Rigging, and Tree Removal together account for 70% of the written content. Second, because the pass line is 80%, you cannot afford to write off a domain. Even the smallest, Tree Identification and Health at 10%, represents roughly five scored questions, and missing most of them would put real pressure on the rest of your score.

These headings and weights are the official written-exam objectives, not chapters of a prep book and not allocations of practical stations. For a fuller walkthrough, see our complete guide to all five CTW content areas. Some older chapter summaries and renewal prose still reference an eight-domain scheme; the current outline is five domains.

What a Miss Costs: Retake Rules and Fees

Knowing the passing score also means knowing the price of falling short. If you do not pass, you must wait 30 days before retaking, and the retake fee is $120. (One competing site lists a $75 retake fee; that figure does not match the current issuer guide.)

For first-time costs, the application fee is $40 for ISA members or current ISA credential holders, or $50 for others, plus the enrollment fee. Be aware that ISA's own materials currently disagree on enrollment: the August 2025 Program Guide and Exam Information page list standard enrollment at $369, while the Common Questions table says $396. We are flagging that conflict rather than picking a side, so confirm the current amount with ISA at the time you apply. A discounted-group enrollment rate of $295 also appears in ISA's materials. Current pricing does not vary by delivery method, and the old computer-testing surcharge no longer applies. Our CTW certification cost breakdown lays out the full fee picture.

After approval, Pearson VUE's authorization window is 120 days, and you must present two forms of identification whose names match your application. Plan your scheduling accordingly using our guide to CTW exam dates and scheduling.

Skills Waivers: What They Cover and What They Don't

There is an approved competition-based waiver, but candidates often assume it is bigger than it is. It concerns the work-climb portion only. To use it, you must have completed all specified TCC/ITCC events, and you still must complete the gear inspection, the six knots, and the evaluator documentation. It is not a blanket waiver of the skills requirements, and it does not waive the written exam.

Separately, a reciprocity application exists for current EAC European Tree Worker climbing holders (form version 08.2026), requiring verification and a $220 fee. That is its own route, not a substitution for ISA's standard process, and it should not be confused with the credential you are working toward here.

Outdated Numbers You May Still See Online

Because the program changed, plenty of older pages still circulate with stale details. Here are the discrepancies worth knowing:

• Eight domains: Older summaries and some chapter training pages still show an eight-domain outline. The current outline has five.
• 30-minute practical limit: Some pages describe 30 minutes as the limit. Under current rules, 30 minutes is the full-credit target; the maximum is 45.
• 65 scored plus 15 unscored: The correct reading is 65 total, 15 unscored, 50 scored.
• Reversed percentages: Older handbooks reverse the written and skills thresholds. Current: 80% written, 70% skills.
• Former name: "Certified Tree Worker Climber Specialist" is the earlier name for this same credential, renamed in 2023.

The August 2025 Program Guide established the current scheme. The issuer's own change notice contains a minor internal inconsistency on the effective date (May 1, 2024 in the narrative versus January 1, 2024 in a table heading), so when in doubt, rely on the current Program Guide and Exam Information page rather than any aggregator. If you are unsure what the credential is at its core, our explainer on what CTW certification is is a good orientation.

Matching Your Prep to the Scoring Rules

Since you face two different thresholds, your preparation should split into two tracks that run in parallel. One short, CTW-specific schedule works well:

The Tree Climbers' Guide, Fourth Edition (2021), is the official ISA preparation publication, but ISA states that the book and the certification exams are developed through separate processes. It is a study aid, not a substitute for the examination outline, so keep the outline as your coverage checklist. Our CTW study guide goes deeper on building a plan, and our one-page CTW cheat sheet is handy for last-minute review of the numbers in this article.

Frequently Asked Questions

Once you understand exactly what the scoring requires, the next step is measuring yourself against it. You can try realistic, domain-weighted questions on our main practice test site, and if you are weighing whether the credential is worth the effort, our analysis of whether CTW certification is worth it walks through the evidence honestly.