RD Exam Domains: The Four 2027–2031 Domains, Percentages and What Each Covers

The four RD exam domains and their percentages

CDR's 2027–2031 test specifications, approved on June 25, 2025, apply to every RD exam appointment from January 1, 2027:

The last column is Passy's arithmetic, not a CDR figure: each weight applied to the 100 to 120 scored questions the handbook describes. CDR doesn't publish item counts per domain, and an adaptive exam draws a different set for each candidate. Another 25 questions are unscored pretest items you can't tell apart from the rest.

You won't see the domains as sections. CDR's handbook says questions from any domain can appear anywhere in the exam and don't come in content order, so a food safety question can follow a tube-feeding calculation. The RD exam format guide covers the question count and the clock.

Domain I: Fundamentals of Dietetics Practice (23%)

Parts: A. Management and Leadership; B. Marketing and Public Relations; C. Research Applications; D. Professional Practice.

What the outline names: leadership and management styles, change management, conflict resolution, human resources (employment laws, interviewing and selection, performance evaluation, compensation), the marketing mix, study design, the Institutional Review Board, statistical analysis, the Scope and Standards of Practice, the Code of Ethics and HIPAA. Quality improvement sits here too, with cost/benefit, productivity, and program and product analysis.

Where to go next: the RD exam Domain I guide explains each part, and the foodservice math guide works the management calculations.

Domain II: Community and Public Health Nutrition (22%)

Parts: A. Community Nutrition Guidelines and Policies; B. Community Needs Assessment; C. Community Nutrition Programs and Services for Individuals and Groups.

What the outline names: federal programs such as WIC, SNAP, the School Breakfast and National School Lunch programs, CACFP and SNAP-Ed; policy such as the Older Americans Act and the Farm Bill; the Dietary Guidelines for Americans, Dietary Reference Intakes and Healthy People; surveillance systems (NHANES, BRFSS, YRBSS); social determinants of health; the Social-Ecological Model, the Logic Model, and primary, secondary and tertiary prevention. Nutrition education theories, counseling techniques and the types of program evaluation are listed here as well.

Where to go next: the RD exam Domain II guide sorts the programs, data sources and models.

Domain III: Human Nutrition and Medical Nutrition Therapy (40%)

Parts: A. Fundamentals of Human Nutrition and Physiology; B. Screening and Assessment; C. Diagnosis; D. Planning and Intervention; E. Monitoring and Evaluation.

What the outline names: nutrient functions, physiology by body system and needs across the life span; nutrition screening; assessment, including the nutrition-focused physical exam, biochemical data and medication, food and supplement interactions; the Academy/ASPEN and GLIM malnutrition guidelines; medical nutrition therapy across 14 groups of conditions, from critical care to wounds and amputations; and oral, enteral and parenteral feeding, with "Formulas and calculations" listed by name.

Where to go next: the RD exam Domain III guide follows the domain step by step, and the clinical calculations guide works the formulas. Domain III is also the largest share of the full prep planned for launch: you can compare the planned question and flashcard counts for all four domains, from 680 questions here to 255 for Domain IV.

Domain IV: Food Science and Food Systems (15%)

Parts: A. Food Science; B. Menu Development; C. Flow of Food from Procurement to Service.

What the outline names: labeling and packaging claims, the physical and chemical properties of foods, functions of ingredients and food additives; menu types (cycle, static, single-use) and plate waste; inventory management, standardized recipes, portion control and yield analysis, forecasting production; HACCP, final internal temperatures, the temperature danger zone, cooling and reheating; emergency preparedness and sustainability practices.

Where to go next: the RD exam Domain IV guide has the food safety numbers and the menu and production topics.

Why "Domain 1" means something different from 2027

Both outlines number their domains I to IV, but the content behind each number changed:

So a "Domain II" chapter in a book written for 2022–2026 is clinical nutrition care, which is Domain III from 2027. A "Domain III" deck from the same period is management, most of which now sits in Domain I. The 2027 changes guide maps each old topic to its new place, line by line.

CDR's own free practice set shows the problem. It's dated September 2024, before the new specifications were approved, and its answer key codes a forecasting question IV.B and a statistics question I.D. In the 2027–2031 outline, IV.B is Menu Development and I.D is Professional Practice, while forecasting sits under IV.C and statistical analysis under I.C. Sort practice questions by topic, not by the code printed next to them.

Which RD exam domains apply to your test date

The date of your appointment decides, not the date you became eligible:

• On or before December 31, 2026: the 2022–2026 domains (21%, 45%, 21%, 13%).
• On or after January 1, 2027: the four domains on this page.

As checked on November 6, 2026, CDR's Examination Resources page lists both outlines side by side, and the handbook it links is the 2026 edition, which prints the 2022–2026 domains. A retake can cross the line too: CDR lets you retest 46 days after an unsuccessful attempt, so by Passy's count a failed attempt on November 16, 2026 or later puts the retake under the new domains. The RD exam retake guide has the dates.

How to split study time across the RD exam domains

CDR doesn't recommend a number of study hours, but the weights give you the split. Out of every 10 hours, that's about 4 for Domain III, a little over 2 each for Domains I and II, and 1.5 for Domain IV (Passy's arithmetic from the weights).

Start from that split, then move hours toward the domain your practice shows is weakest. The RD exam study plan guide turns the weights into 8- and 12-week schedules, and the free RD exam study planner builds one from your test date. At launch, you'll also be able to see how planned full prep names the domain to focus on next, based on your accuracy in each of the four.

To find your starting point now, the 20 free RD exam practice questions are mixed across the four 2027–2031 domains, each with an explanation.

Checking your study materials against the four domains

Three quick checks tell you which outline a book, deck or question set follows:

1. The domain names. "Principles of Dietetics" or "Foodservice Systems" as a domain title means 2022–2026.
2. The weights. 21/45/21/13 is the outgoing outline. 23/22/40/15 is the new one.
3. The date. Anything published before June 25, 2025 was written before CDR approved the new specifications.

Older material isn't useless, because most topics moved rather than disappeared. It just needs re-sorting. The RD exam study materials guide goes through CDR's free resources one by one and shows which ones still carry the old labels.

Full Passy prep for this exam isn't on sale yet. It's being written for the four 2027–2031 domains, and you can join the waitlist for RD exam prep organized by the new domains on the exam page.