1.1 Current Exam Facts
Key Takeaways
- The CDR Registration Examination for Dietitians delivers 125-145 computer-adaptive questions in a 2.5-hour testing window inside a roughly 3-hour Pearson VUE appointment.
- Scores are reported on a 1-50 scale, and a scaled score of 25 is the passing standard for the RD exam.
- The exam fee is $250, payable to the Commission on Dietetic Registration after you receive authorization to test.
- Of the 125-145 items, about 100-120 are scored and roughly 25 are unscored pretest questions that do not affect your result.
- Unsuccessful candidates must wait 45 days, reauthorize, and pay the fee again before retaking the RD exam.
About the CDR Registered Dietitian (RD) Exam
Quick Answer: The Registration Examination for Dietitians is a computer-adaptive test (CAT) of 125-145 questions delivered in a 2.5-hour testing window inside a roughly 3-hour appointment at Pearson VUE. It costs $250, is scored on a 1-50 scale, and you pass with a scaled score of 25. A failed attempt means a 45-day wait before you can reauthorize and retake.
The RD exam is administered by the Commission on Dietetic Registration (CDR), the credentialing agency of the Academy of Nutrition and Dietetics. Passing it earns the Registered Dietitian (RD) credential, which CDR also lets you use as Registered Dietitian Nutritionist (RDN) — the two are interchangeable.
Exam at a Glance
| Detail | Information |
|---|---|
| Administering body | Commission on Dietetic Registration (CDR) |
| Delivery | Computer-adaptive test (CAT) at Pearson VUE centers |
| Total questions | 125-145 (about 100-120 scored + ~25 unscored pretest) |
| Testing time | 2.5 hours |
| Appointment length | ~3 hours (includes check-in and tutorial) |
| Fee | $250 |
| Score scale | 1 to 50 |
| Passing score | Scaled score of 25 |
| Retake wait | 45 days |
Why the Question Count Varies
Because the RD exam is adaptive, the software stops once it has enough evidence to place you confidently above or below the passing standard. A candidate whose ability is clearly far from the cut score may finish near the 125-item minimum; a candidate hovering near the standard answers more items — up to the 145 maximum — so the engine can decide. Either way, the test ends when the 2.5-hour clock runs out or the maximum item count is reached. Note the floor matters: if you do not complete at least 125 items within the time limit, the result is scored as a fail.
What the $250 Buys
The $250 fee covers one authorized attempt. This is the current price as of 2026 — CDR raised the fee from $225 to $250 effective June 1, 2025, so older study materials that quote $225 are out of date. CDR issues an authorization to test (ATT) that you must hold before scheduling with Pearson VUE; that authorization is valid for one year or until you sit for the exam, whichever comes first. If the ATT lapses unused, you must re-apply and pay again. There is no discount for retaking unless you purchased a Pearson VUE test bundle that includes a retake voucher.
RD vs. RDN: One Credential, Two Titles
A frequent point of confusion: RD (Registered Dietitian) and RDN (Registered Dietitian Nutritionist) are the same credential. CDR introduced "RDN" in 2013 to emphasize the nutrition scope of practice, but it carries no separate exam, fee, or eligibility path. You sit for one exam; on passing you may use either set of initials. Many states layer a separate licensure or certification (e.g., LD, LDN) on top of the RD credential for legal practice — that is a state board matter, not part of the CDR exam.
Test-Day Logistics
| Item | Detail |
|---|---|
| What to bring | Two forms of valid ID; primary must be government-issued photo ID with signature |
| Allowed in room | On-screen four-function calculator; erasable noteboard provided |
| Not allowed | Phones, smartwatches, personal notes, food/drink at the workstation |
| Tutorial | A short, untimed tutorial precedes the 2.5-hour clock |
| Results | Preliminary pass/fail shown on screen; official letter follows |
Arrive at least 30 minutes early. A late arrival can be treated as a no-show, forfeiting the $250 fee and requiring re-authorization. Plan around the ~3-hour appointment, not just the 2.5-hour test clock.
Scheduling and Rescheduling
After CDR issues your authorization to test, you book a seat through Pearson VUE (online or by phone). Seats are first-come, first-served, and high-demand testing windows fill weeks ahead — schedule early. Pearson VUE's standard policy lets you reschedule or cancel without penalty up to a cutoff (commonly two business days before the appointment); inside that window you forfeit the seat and fee. Because the $250 is non-refundable once you are inside the cancellation window, lock in a date you can realistically keep, then build your study calendar backward from it.
What Happens When You Pass
You typically see an unofficial pass/fail result on screen at the end of the session, but it is preliminary. CDR issues the official result afterward and, on a passing result, confers the RD/RDN credential. You then begin a continuing professional education (CPE) cycle: registered dietitians must complete 75 CPE units every five years to maintain registration, and CDR's Professional Development Portfolio (PDP) is the system used to plan, log, and report that learning. Passing the exam is the entry point, not the finish line.
If You Don't Pass
A failing result is not the end of the road. CDR places no lifetime limit on attempts; you simply must observe the 45-day wait, obtain a fresh authorization, and pay the $250 again for each new attempt. Use the wait productively: your score report breaks performance down by the four content domains, so target your weakest domain first rather than re-studying everything evenly.
What scaled score do you need to pass the CDR Registered Dietitian exam?
A candidate fails the RD exam. What must happen before they can test again?