HESI A2 Hardest Sections Ranked 2026: Where to Focus Your Study Time

HESI A2 Hardest Sections Ranked: A Commonly-Reported Difficulty Guide for 2026

The HESI A2 (Health Education Systems, Inc. Admission Assessment) is the gateway to nursing school for hundreds of thousands of applicants every year. But not all sections are created equal — some are dramatically harder than others, and knowing where to focus your limited study time can mean the difference between admission and rejection.

Student-reported scores vary widely, and there is no single official per-section pass rate published by Elsevier. What follows is a difficulty ranking based on what students and tutors most commonly report, combined with the structure and content scope of each section as described in the official HESI A2 exam guide.

This guide ranks the HESI A2 sections by commonly-reported difficulty and gives you a targeted study plan for each one.

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HESI A2 Sections at a Glance

The HESI A2 is modular — each nursing program selects which sections to require. Up to 9 academic sections are available, though most schools require only 4–7. Here is the full section list with question counts and time limits as described in Elsevier's exam materials:

Question counts and time limits can vary slightly by administering institution. Always confirm with your target school.

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How the HESI A2 Sections Are Scored

Before diving into the rankings, here's what you need to know about HESI A2 scoring:

Critical note: Each nursing program chooses which sections to require, what minimum scores to accept, and what retake rules apply. There is no single universal retake policy or score-validity window — always check your target school's specific requirements before registering.

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The HESI A2 Sections Ranked by Commonly-Reported Difficulty

The ranking below reflects what students and tutors most frequently report, not an official Elsevier difficulty index. Your personal experience may differ based on your academic background — a student who recently completed A&P coursework will find that section far easier than someone who last studied biology a decade ago.

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#1 — Anatomy & Physiology (Hardest)

Why it's commonly reported as the hardest: This section requires you to know 11 body systems in detail — their structures, functions, and interactions. Unlike other sections that test skills you've used your whole life (reading, grammar, basic math), A&P demands specialized knowledge that most students haven't studied since high school biology, if at all. Multiple test-prep sources and student surveys consistently identify A&P as the most challenging HESI A2 section.

Key topics to master:

• Cardiovascular system — Heart chambers, blood flow pathway, major vessels
• Endocrine system — Glands, hormones, feedback loops
• Nervous system — CNS vs. PNS, neuron structure, reflex arcs
• Musculoskeletal system — Major bones, muscle types, joint classifications
• Directional terminology — Superior/inferior, medial/lateral, proximal/distal

Study strategy:

1. Start with directional terms and body planes — these appear on nearly every HESI A2
2. Focus on high-yield systems: cardiovascular, endocrine, and nervous
3. Use visual diagrams rather than text-only study — anatomy is inherently visual
4. Learn at the "overview" level, not the "medical school" level — know which hormones come from the pituitary gland, but you don't need to memorize every releasing factor

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#2 — Biology

Why it's commonly reported as second hardest: Biology covers cell biology, metabolism, genetics, and cellular respiration — content that many nursing applicants haven't studied in years. Test-prep sources frequently rank Biology as the second most challenging section after A&P, because it requires genuine understanding of cellular processes rather than simple memorization.

Key topics to master:

• Cell structure — Organelles, membrane transport, cellular respiration
• Genetics — Mitosis vs. meiosis, Punnett squares, inheritance patterns
• Biological molecules — Carbohydrates, lipids, proteins, nucleic acids
• Metabolism — Photosynthesis, cellular respiration, ATP production
• Scientific method — Hypothesis, experiment, evaluation, conclusion

Study strategy:

1. Master the cell organelles and their functions first — nearly every Biology exam includes cell structure questions
2. Draw out the stages of mitosis and meiosis side by side to see the differences clearly
3. Practice Punnett square problems until monohybrid and dihybrid crosses are automatic
4. Focus on cellular respiration (glycolysis, Krebs cycle, electron transport chain) — it is a high-yield topic

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#3 — Chemistry

Why it's hard: Many nursing applicants haven't taken chemistry since high school, and the HESI A2 chemistry section requires understanding of concepts like the periodic table, chemical reactions, solutions, and biochemistry basics that feel unfamiliar after years away.

Key topics to master:

• Atomic structure — Protons, neutrons, electrons, electron shells
• Periodic table — Groups, periods, element properties
• Chemical bonds — Ionic vs. covalent vs. hydrogen bonds
• Solutions — Concentration, dilution, pH scale, acids/bases
• Biochemistry basics — Carbohydrates, lipids, proteins, nucleic acids

Study strategy:

1. Start with the periodic table structure — understanding groups and periods unlocks many questions
2. Memorize the pH scale (0–14) and what makes acids vs. bases
3. Practice balancing simple chemical equations
4. Focus on biochemistry basics since these connect directly to nursing coursework

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#4 — Mathematics

Why it's moderately hard: The math itself is basic (no calculus, no advanced algebra), but the HESI A2 math section is harder than most students expect because it tests dosage calculations, unit conversions, fractions, decimals, and ratios — all without notes. Many students make careless errors under time pressure.

Key topics to master:

• Fractions — Adding, subtracting, multiplying, dividing, converting to decimals
• Ratios and proportions — Cross-multiplication, ratio word problems
• Unit conversions — Metric ↔ household measurements, temperature conversions
• Percentages — Finding percentages, percentage increase/decrease
• Roman numerals — Used in medical prescriptions and dosage orders

Study strategy:

1. Memorize conversion factors: 1 kg = 2.2 lbs, 1 inch = 2.54 cm, 1 oz = 30 mL
2. Practice fraction operations daily — these are the most common error source
3. Work through ratio/proportion problems using cross-multiplication
4. Practice with the on-screen calculator style (don't rely on your phone's calculator)

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#5 — Reading Comprehension

Why it's moderate: Most students do reasonably well here because reading skills transfer from everyday life. However, the passages are dense medical/health topics, and the questions test inference and critical analysis rather than simple recall.

Study strategy:

1. Read the questions before the passage — know what you're looking for
2. Practice identifying main ideas vs. supporting details
3. For inference questions, choose the answer supported by the text, not your outside knowledge
4. Read health-related articles regularly to build comfort with medical terminology

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#6 — Vocabulary & General Knowledge

Why it's easier: This section tests everyday English vocabulary plus medical/healthcare terms. Students who read regularly tend to score well, and the vocabulary is learnable through flashcard-style study.

Study strategy:

1. Learn common medical prefixes (hyper-, hypo-, brady-, tachy-) and suffixes (-itis, -ectomy, -ology)
2. Use flashcards for the top 200 HESI A2 vocabulary words
3. Study words in context rather than isolated definitions
4. Focus on words commonly used in healthcare settings

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#7 — Grammar (Easiest of the Core Sections)

Why it's the easiest: Grammar rules are finite, and most students have a working knowledge from years of English classes. The questions test standard grammar conventions that are straightforward to review.

Study strategy:

1. Review the top 10 grammar rules: subject-verb agreement, pronoun-antecedent agreement, comma rules, semicolons, apostrophes
2. Practice identifying sentence fragments and run-on sentences
3. Focus on commonly confused words (affect/effect, their/there/they're, then/than)
4. Take a quick grammar diagnostic to find your specific weak spots

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#8 — Physics (Rarely Required)

Why it's situational: Physics is rarely required by nursing programs, but if your school does require it, expect a challenge. The section covers Newton's laws, motion, energy, waves, optics, and projectile motion — topics most nursing applicants have never studied in a healthcare context.

Study strategy:

1. Confirm whether your school actually requires Physics before investing study time
2. If required, focus on Newton's laws of motion and energy conservation — these are the highest-yield topics
3. Practice solving basic kinematics problems involving speed, velocity, and acceleration
4. Review wave properties (frequency, wavelength, amplitude) and the electromagnetic spectrum

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#9 — Critical Thinking (Optional)

Why it's optional and school-set: The Critical Thinking section is not required by all programs. When it is included, it presents scenario-based questions that assess clinical reasoning, prioritization, and problem-solving. There is no content to memorize — it measures how you apply logic to unfamiliar situations.

Study strategy:

1. Check whether your school requires this section — many do not
2. Practice situational judgment questions that ask you to prioritize patient needs
3. Read each scenario carefully and choose the most logical, safety-first response
4. Do not overthink — the best answer is usually the one that prioritizes patient safety and follows protocol

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Recommended Study Timeline by Section

Total recommended study time: 50–70 hours over 6–8 weeks. Students who have not taken science courses in several years should plan for 8–10 weeks, particularly to rebuild A&P and Biology content.

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6 Common Mistakes That Cost Students Points

1. Studying All Sections Equally

Students often split their time evenly across all sections. This is a mistake. A&P, Biology, and Chemistry need 2–3x more study time than Grammar or Vocabulary.

2. Ignoring the On-Screen Calculator

The HESI A2 provides an on-screen calculator for math — but many students never practice with one. The interface is different from your phone's calculator. Practice with it beforehand.

3. Cramming Anatomy & Physiology

A&P has too much material to cram in a few days. You need spaced repetition over at least 2–3 weeks to retain 11 body systems.

4. Skipping Practice Tests

Practice tests reveal your actual weak spots and build test-day stamina. Take at least 2–3 full-length practice tests before your real exam.

5. Not Checking School-Specific Requirements

Some schools only require 4 sections. Others require 7. Some need an 80% minimum. Others want 90%+. Studying for sections your school doesn't require wastes valuable time.

6. Assuming a Universal Retake Policy

Retake rules are set by each nursing program, not by Elsevier. Common policies allow a 30–60 day wait between attempts and 2–3 retakes per year, but some schools impose stricter or different limits. Always confirm your school's retake policy before scheduling.

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Score Requirements by Nursing Program Type

Minimums vary by institution. Always verify with your target program.

Pro tip: Aim for at least 5–10 points above your program's minimum. Admission is competitive, and higher HESI A2 scores can compensate for a lower GPA.

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Start Studying the Hardest Sections First

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Don't let Anatomy & Physiology, Biology, or Chemistry catch you off guard. Our free study guide walks you through every section with targeted lessons and practice questions. Start with the hardest sections first and build your confidence.

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Official Resources

• Elsevier HESI A2 Information — Official exam registration and details
• HESI A2 Practice Tests — Official practice tests from Elsevier
• U.S. Bureau of Labor Statistics — Registered Nurses — RN career outlook and wage data