ISA Certified Arborist Pass Rate, Format & Study Guide

The ISA program guide (revised August 2025) lists the Certified Arborist exam as a computer-based multiple-choice exam with 200 questions, and ISA sets the passing score at 76 percent. The exam outline weights ten areas: Tree Biology 11 percent, Tree Identification and Selection 9, Soil Management 7, Installation and Establishment 9, Pruning 14, Diagnosis and Treatment 9, Trees and Construction 9, Tree Risk 11, Safe Work Practices 15 and Urban Forestry 6. ISA lists a $40 application fee for members and credential holders ($50 for others) and an exam enrollment fee of $295 for members ($369 for others) with an approved application; enrollments are not refunded.

The ISA Certified Arborist credential is a widely recognized mark of knowledge for tree care professionals and is often asked for by employers and municipalities.

Tree care professionals, utility and municipal arborists, and landscape workers with arboriculture experience.

The certifying body does not publicly publish an official pass rate for this exam. Be wary of third-party sites citing a specific number here — treat any pass-rate claim you see elsewhere for this exam as unverified.

ISA lists a member retake fee of $120 on its pricing table. The sources used here do not describe the Certified Arborist retake rules, so read the current program guide before you rebook.

ISA sets the passing score for the Certified Arborist exam at 76 percent, and because the areas are weighted, the average of your area scores does not equal your overall score. The portal mock uses 76 percent only as a self-check. Format: 200 multiple-choice questions on a computer, passing score 76 percent. No official pass rate is available for this exam, so none is quoted here.

The ISA program guide (revised August 2025) lists the Certified Arborist exam as a computer-based multiple-choice exam with 200 questions, and ISA sets the passing score at 76 percent. The exam outline weights ten areas: Tree Biology 11 percent, Tree Identification and Selection 9, Soil Management 7, Installation and Establishment 9, Pruning 14, Diagnosis and Treatment 9, Trees and Construction 9, Tree Risk 11, Safe Work Practices 15 and Urban Forestry 6. ISA lists a $40 application fee for members and credential holders ($50 for others) and an exam enrollment fee of $295 for members ($369 for others) with an approved application; enrollments are not refunded. 200 multiple-choice questions · computer-based · passing score 76 percent. ISA sets the passing score for the Certified Arborist exam at 76 percent, and because the areas are weighted, the average of your area scores does not equal your overall score. The portal mock uses 76 percent only as a self-check.

• Tree Biology11%
• Tree Identification and Selection9%
• Soil Management7%
• Installation and Establishment9%
• Pruning14%
• Diagnosis and Treatment9%
• Trees and Construction9%
• Tree Risk11%
• Safe Work Practices15%
• Urban Forestry6%

The content outline spreads questions across 10 areas: Tree Biology (11.0%); Tree Identification and Selection (9.0%); Soil Management (7.0%); Installation and Establishment (9.0%); Pruning (14.0%); Diagnosis and Treatment (9.0%); Trees and Construction (9.0%); Tree Risk (11.0%); Safe Work Practices (15.0%); Urban Forestry (6.0%).

ISA requires a minimum of three years of full-time experience in arboriculture, or a combination of education and practical arboricultural experience. A four-year bachelor degree with at least four courses directly related to arboriculture plus one year of full-time experience qualifies; supervised, documented volunteer work can count.

Application $40 (members) or $50 (others) plus exam enrollment $295 (members) or $369 (others); retake fee $120 for members.

ISA offers two routes to recertify: retake and pass the exam, or earn continuing education units over the three-year certification period; check the program guide for the CEU count and fee.

Start with the heaviest areas of the content outline: Safe Work Practices (15.0%); Pruning (14.0%); Tree Biology (11.0%). Then work through the remaining areas, and finish with timed full-length practice runs of 200 questions in one sitting.

ISA revises its program guide and pricing; this guide follows the August 2025 program guide and the July 2025 pricing as of October 2026.