Fatigue Severity Scale (FSS) Calculator

Rate each statement from 1 (strongly disagree) to 7 (strongly agree) based on how you've felt over the past week.

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Mean FSS Score (range 1–7)
Cutoff: 4
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What is the Fatigue Severity Scale?

The Fatigue Severity Scale (FSS) is a self-assessment questionnaire developed by Lauren Krupp and colleagues in 1989. It was designed to measure the severity of fatigue and its effect on a person's activities and lifestyle. The FSS is widely used to assess fatigue in various medical conditions including:

  • Multiple sclerosis (MS)
  • Systemic lupus erythematosus (SLE)
  • Chronic fatigue syndrome
  • Parkinson's disease
  • Post-viral fatigue
  • Depression

How is the FSS Scored?

The FSS consists of 9 statements. Each is rated on a 7-point Likert scale:

  • 1 = Strongly disagree
  • 7 = Strongly agree

The final FSS score is the mean (average) of all 9 item scores:

FSS Score = (Item 1 + Item 2 + ... + Item 9) / 9

Interpretation

Mean FSS Score Interpretation
< 4 No clinically significant fatigue
≥ 4 Clinically significant fatigue — may warrant further evaluation

A score of 4 or higher suggests significant fatigue that may be impacting daily life. In the original study by Krupp et al., healthy controls had a mean score of approximately 2.3 ± 0.7, while patients with MS had a mean of 4.8 ± 1.3.

Understanding the 9 FSS Items

  1. Motivation and fatigue — Does fatigue reduce your motivation?
  2. Exercise and fatigue — Does exercise cause fatigue?
  3. Ease of fatigue — Are you easily fatigued?
  4. Physical functioning — Does fatigue interfere with physical activities?
  5. Frequency of problems — Does fatigue frequently cause issues?
  6. Sustained functioning — Does fatigue prevent sustained physical effort?
  7. Duties and responsibilities — Does fatigue interfere with duties?
  8. Most disabling symptoms — Is fatigue among your top 3 disabling symptoms?
  9. Work, family, and social life — Does fatigue interfere with these domains?

Limitations

  • The FSS measures subjective fatigue — it relies on self-reporting
  • It assesses physical fatigue more than cognitive or emotional fatigue
  • The cutoff of 4 is a general guideline; clinical context matters
  • This tool does not diagnose any medical condition

If your FSS score indicates significant fatigue, consult a healthcare professional for proper evaluation and diagnosis.

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