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Fatigue Severity Scale Calculator

Created by Mariamy Chrdileli
Reviewed by Anna Szczepanek, PhD and Adena Benn
Based on research by
Krupp LB, LaRocca NG, Muir-Nash J, Steinberg AD. The fatigue severity scale. Application to patients with multiple sclerosis and systemic lupus erythematosus.; Archives of neurology; 1989
Last updated: Jan 18, 2024

The Omni fatigue severity scale calculator is a simple tool that assesses fatigue severity in various patient populations.

Conditions such as multiple sclerosis, systemic lupus erythematosus, arthritis, stroke, and fibromyalgia are often accompanied by fatigue. Fatigue involves many physical, mental, and emotional symptoms that can significantly affect one's quality of life. Hence, assessing the severity of it can be crucial for determining the appropriate treatment plan.

If you're struggling with fatigue and want to know more about the fatigue severity scale (FSS), you're in the right place. Come along to get clear answers to some of the FSS assessment-related questions, such as:

  • What are the symptoms of fatigue?
  • What is the FSS assessment?
  • How do you score the FSS?
  • What are other fatigue assessment scales? And more.

While you're here, you can also check the Epworth Sleepiness Scale calculator or Pediatric Epworth sleepiness scale to screen for excessive daytime sleepiness.

❗ Note that you should consult a healthcare professional if you are suffering from fatigue. Additional assessments may be necessary to determine the severity and impact of fatigue on daily life.

What is the fatigue severity scale (FSS) assessment?

Let's start from the beginning — what are the symptoms of fatigue? The symptoms of fatigue include:

  • Chronic feelings of exhaustion and tiredness;
  • Lack of motivation;
  • Anxiety and irritability.
  • Dizziness;
  • Sleep distrubances;
  • Cognitive disturbances, such as memory problems, lack of focus, and concentration;
  • Impaired decision-making;
  • Muscle weakness and pain; and
  • Slowed reflexes.

The fatigue severity scale (FSS) is a 9-item self-reported assessment tool for determining the severity of fatigue. The scale was initially developed by Dr. Lauren Krupp and colleagues (1989) to assess fatigue severity in patients with multiple sclerosis and systemic lupus erythematosus; however, nowadays, it is utilized by many patient populations, including those with stroke, fibromyalgia, and arthritis. The questionnaire takes an average of eight minutes to complete and can determine fatigue severity levels.

The fatigue severity scale scoring

Although you won't have to manually compute anything with the fatigue severity scale calculator, here is how the FSS scoring works.

  1. Each item is evaluated on a 7-point scale (1 = strongly disagree and 7 = strongly agree).
  2. The final score, which can range from 1 to 7, is determined by calculating the average (i.e., dividing the total score of all of the items by 9).

The higher the score, the more significant the adverse effects of fatigue on a person's daily functioning; most studies agree that those who score above 4 are struggling with clinically significant fatigue.

🔎 Did you know that 38 to 73% of people experience post-stroke fatigue (PSF)? You can assess other impairments caused by a stroke with the NIH stroke scale calculator.

How does the fatigue severity scale calculator work?

Using the fatigue severity scale calculator is quite simple. Read each statement and rate how accurately they reflect your condition during the past week.

Ultimately, the calculator will determine your FSS score, ranging from 1 to 7. As mentioned above, the higher scores indicate a more significant negative impact of fatigue on a person's functioning, and the cut-off score of 4 indicates problematic fatigue levels.


How do I score the fatigue severity scale?

To score the fatigue severity scale, you can follow the next steps:

  1. Sum the scores of the nine items.
  2. Calculate the average score by dividing the number computed in step 1 by 9.
  3. That's all! Your calculated score for the fatigue severity scale will range from 1 to 7.

What does a score of 2.3 indicate on the fatigue severity scale?

An FSS score of 2.3 indicates that the person is not experiencing clinically significant fatigue. For instance, the study conducted by Grace and colleagues (2006) revealed that the average FSS score for healthy individuals is 2.3.

What does a score of 4 indicate on the fatigue severity scale?

An FSS score of 4 indicates clinically significant fatigue levels. If you're suffering from fatigue, address the issue with a healthcare professional to identify appropriate strategies and interventions that can help you mitigate symptoms.

What are the most used fatigue assessment scales besides FSS scale?

Some of the most widely used fatigue scales beside the FSS are:

  • The brief fatigue inventory (BFI);
  • The modified fatigue impact scale (MFIS);
  • The fatigue numeric rating scale (NRS);
  • The visual analog fatigue scale (VAFS); and
  • The functional assessment of chronic illness therapy — fatigue (FACIT-F).
Mariamy Chrdileli
Read each statement carefully and choose a response that best describes your condition within the last week.
My motivation is lower when I am fatigued.
Exercise brings on my fatigue.
I am easily fatigued.
Fatigue interferes with my physical functioning.
Fatigue causes frequent problems for me.
My fatigue prevents sustained physical functioning.
Fatigue interferes with carrying out certain duties and responsibilities.
Fatigue is among my three most disabling symptoms.
Fatigue interferes with my work, family, or social life.
Fatigue Severity Score (FSS)
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