CDAI Calculator (Crohn's Disease Activity Index)

Crohn’s Disease Activity Index (CDAI) for disease-activity grading.

For educational and clinical reference. Not a substitute for medical judgment. See the medical disclaimer.

Liquid/soft stools — 7-day total

Abdominal pain — 7-day sum (0–3/day)

General well-being — 7-day sum (0–4/day)

Number of complications (0–6)

Antidiarrheal / opiate use for diarrhea

Abdominal mass

Hematocrit (%)

Sex (for hematocrit reference)

Current weight (kg)

Standard (ideal) weight (kg)

CDAI

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Disease activity

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References

Best WR, Becktel JM, Singleton JW, Kern F Jr. Development of a Crohn’s disease activity index. National Cooperative Crohn’s Disease Study. Gastroenterology. 1976;70(3):439-444.

How to use

Enter the 7-day sums for stools, abdominal pain, and well-being.
Add complications, antidiarrheal use, abdominal mass, hematocrit, and weights.
The CDAI and activity category update instantly (remission < 150).

Frequently asked questions

What is the CDAI?

The Crohn’s Disease Activity Index is the classic research index of Crohn’s disease activity, combining a 7-day symptom diary with examination, complications, hematocrit, and weight.

How is the CDAI interpreted?

< 150 = clinical remission, 150–220 = mild, 221–450 = moderate, > 450 = severe disease activity.

What are the weekly sums?

Add the daily values over 7 days: number of liquid/very soft stools, abdominal-pain rating (0–3/day), and general well-being rating (0–4/day).

How are complications counted?

Count the number present of: arthralgia/arthritis, iritis/uveitis, erythema nodosum/pyoderma/aphthous stomatitis, anal fissure/fistula/abscess, other fistula, and fever > 37.8 °C.

Last updated June 28, 2026