Fatigue Severity Scale Calculator
Score the nine-item Fatigue Severity Scale from 1 to 7 per item and get total, average, and clinical interpretation.
What Is the Fatigue Severity Scale?
The Fatigue Severity Scale (FSS) is a nine-item questionnaire that measures how fatigue affects daily life. Developed by Dr. Lauren Krupp and colleagues, it is used in multiple sclerosis, lupus, fibromyalgia, stroke, and other conditions where fatigue is a major symptom. Each item is scored from 1 (strongly disagree) to 7 (strongly agree). See also the Epworth Sleepiness Scale Calculator for daytime sleepiness screening.
How the FSS Is Scored
Add all nine item scores for a total between 9 and 63. The average score (total divided by 9) ranges from 1 to 7. A total score above 36 or an average above 4 often indicates clinically significant fatigue. Healthy adults frequently score around 2 to 3 on average.
Interpreting Your Results
Higher scores mean fatigue has a greater impact on motivation, physical function, work, and social life. The FSS is a screening and monitoring tool, not a standalone diagnosis. Persistent or worsening fatigue should be discussed with a healthcare provider who can identify underlying causes and treatment options.
When to Seek Medical Advice
Consult a clinician if fatigue limits your daily activities, does not improve with rest, or accompanies other symptoms such as weight change, pain, sleep disturbance, or mood changes. Additional assessment may include blood tests, sleep evaluation, or condition-specific workups.
Frequently Asked Questions
What is a normal FSS score?
Healthy individuals often average around 2 to 3 on the FSS (total roughly 18 to 27). Scores vary by population and should be interpreted in clinical context.
What score indicates significant fatigue?
A total score above 36 or an average above 4 is commonly used as a threshold for clinically significant fatigue in research and practice.
How long does the FSS take to complete?
Most people finish the nine statements in about five to eight minutes. Answer based on the past week for the most accurate snapshot.
Is the FSS only for multiple sclerosis?
No. Although developed for MS and lupus, the FSS is now used across many conditions where fatigue is prominent, including fibromyalgia and post-stroke recovery.
Can fatigue differ from sleepiness?
Yes. Fatigue is a sense of exhaustion and reduced capacity, while sleepiness is the urge to sleep. The Epworth Sleepiness Scale measures sleepiness; the FSS focuses on fatigue impact.
Should I retake the FSS over time?
Retaking the scale after treatment or lifestyle changes helps track improvement or worsening. Use consistent time windows (past week) for comparable results.
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