RD Exam Prep: Passing the CDR Registration Examination for Dietitians
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Every path to becoming a Registered Dietitian (RD) or Registered Dietitian Nutritionist (RDN) runs through the same national exam: the CDR Registration Examination for Dietitians, administered by the Commission on Dietetic Registration (CDR). Here’s what’s actually on it, how it’s scored, and how candidates prepare — see our full path to becoming an RD for the degree and supervised-practice steps that come before it.
What the CDR Exam Is
The Registration Examination for Dietitians is the credentialing exam that turns an eligible candidate — someone who has completed an ACEND-accredited graduate degree and an accredited supervised-practice program — into a Registered Dietitian. It’s a computer-based exam delivered at Pearson VUE testing centers — CDR cites over 250 locations nationwide. Once your program director verifies your eligibility, CDR authorizes you to schedule a test date through Pearson VUE (typically within about a week). Passing it is a single national milestone: the credential itself doesn’t vary by state, even though a separate state license may still be required to practice (see our state-by-state pages).
Domains the Exam Covers
Per CDR’s test specifications currently in effect (January 1, 2022 – December 31, 2026), the exam is organized around four content domains, each with a fixed weighting:
- Principles of Dietetics — 21% — food, nutrition, and supporting sciences; education, communication, and technology; research applications.
- Nutrition Care for Individuals and Groups — 45% — the nutrition care process: screening and assessment, diagnosis, planning and intervention, and monitoring and evaluation. This is the largest single domain by weight.
- Management of Food and Nutrition Programs and Services — 21% — functions of management, human resource management, financial management, marketing/public relations, and quality management and regulatory compliance.
- Foodservice Systems — 13% — menu development; procurement, production, distribution, and service; sanitation and safety; equipment and facility planning.
CDR revises its content outline roughly every five years following a dietetics practice-analysis study — this outline runs through December 31, 2026, and a 2027–2031 specification is already published on CDR’s site for the next cycle, so confirm you’re studying the version that matches your test date.
Format and Passing Standard
Per CDR’s Candidate Handbook, the RD exam is a computer-adaptive, multiple-choice test (four options per question) of variable length: every candidate answers a minimum of 125 questions (100 scored plus 25 unscored pretest questions) and a maximum of 145 (120 scored plus 25 pretest). You get three hours to answer questions, inside a 3.5-hour total testing appointment that also includes a 20-minute tutorial and a 10-minute post-exam survey. Pretest questions aren’t distinguishable from scored ones, so every question should be treated as if it counts.
CDR scores the exam on a scale of 1 to 50; the minimum scaled score required to pass is 25. Because the test is computer-adaptive — question difficulty adjusts to your ongoing performance — the number of questions you need to answer correctly to hit that scaled score isn’t fixed and varies candidate to candidate, so don’t plan around a specific raw-percentage target.
How to Prepare
Your degree program and supervised-practice rotations cover the underlying content, but most candidates still do targeted review before test day — working through the domains above systematically and drilling practice questions in the exam’s format. These are the resources we point candidates to:
Recommended exam prep
Formal prep pays for itself against a retake. These are the resources we point candidates to for the CDR Registration Examination for Dietitians.
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Mometrix · SponsoredRegistration Examination for Dietitians Secrets Study GuideA full review of the CDR Registration Examination for Dietitians — domain-by-domain concept breakdowns and practice questions built for a first-try pass.See the study guide →
Mometrix · SponsoredDietitian Exam FlashcardsPortable flashcards for the high-frequency RD-exam topics — a cheaper add-on for drilling terms and definitions on the go.See the flashcards →Next Steps
Once you’ve passed the CDR exam and hold the RD/RDN credential, most states still require a separate state license before you can use the title or practice for pay. Pick your state below, or read the full path from degree to license.
Frequently Asked Questions
What is the CDR Registration Examination for Dietitians?
It's the national credentialing exam administered by the Commission on Dietetic Registration (CDR). Passing it — after completing an ACEND-accredited degree and supervised practice — is what makes you a Registered Dietitian (RD), also called a Registered Dietitian Nutritionist (RDN). It's a single national exam; separate state licensure requirements (where they exist) are handled afterward, typically by endorsement.
What topics does the RD exam cover?
Per CDR's test specifications in effect January 1, 2022 through December 31, 2026, the exam covers four content domains: Principles of Dietetics (21%), Nutrition Care for Individuals and Groups (45%), Management of Food and Nutrition Programs and Services (21%), and Foodservice Systems (13%). CDR updates its content outline roughly every five years following a practice-analysis study, so confirm you're studying the current outline — a 2027-2031 specification is already published on CDR's site for the next cycle.
How many questions are on the RD exam, and how long do I have?
It's a computer-adaptive, variable-length exam. Per CDR's Candidate Handbook, every candidate answers a minimum of 125 questions (100 scored plus 25 unscored pretest questions) and a maximum of 145 questions (120 scored plus 25 pretest). You get 3 hours to answer questions, inside a 3.5-hour total appointment that also includes a 20-minute tutorial and a 10-minute post-exam survey.
What is the passing score for the RD exam?
CDR scores the exam on a scale of 1 to 50, and the minimum scaled score to pass is 25. Because it's a computer-adaptive test, the number of questions you need to answer correctly to reach that scaled score varies by candidate — the difficulty of the specific questions you receive is factored in, so two candidates can answer a different raw number correct and both pass.
Where and how is the exam administered?
It's a computer-based, multiple-choice exam (four answer options per question) delivered at Pearson VUE professional test centers — CDR cites over 250 locations nationwide plus select international sites. Once your degree and supervised-practice program verify your eligibility, CDR authorizes you to schedule a test date through Pearson VUE, typically within about a week of CDR receiving your eligibility information.