Fatigue Severity Scale Calculator


Fatigue Severity Scale Calculator
Evaluates the impact of fatigue in patients diagnosed with multiple sclerosis or systemic lupus erythematosus.


Hey there, tired folks! Welcome to the Fatigue Severity Scale Calculator! This tool will help you calculate your level of fatigue and provide you with a humorous interpretation of the results.


Do you ever feel like you just can’t shake off that feeling of exhaustion? Do you feel like you’re constantly running on empty, even after a good night’s sleep? If so, you’re not alone. Fatigue is a common symptom that affects millions of people around the world. But how do you know if your fatigue is normal, or if it’s a sign of something more serious? That’s where the Fatigue Severity Scale (FSS) comes in.

The FSS is a self-reported questionnaire used to measure the severity of fatigue in individuals. It consists of a series of questions that ask you to rate how fatigued you feel on a scale of 1-7, with 1 being “no fatigue” and 7 being “very severe fatigue.” The formula for calculating FSS is simple:

FSS = (sum of responses to each item) / (number of items)

Categories of FSS Calculations

The FSS provides a range of scores that can help you interpret your level of fatigue. Here are the categories of FSS calculations and their interpretations:

FSS Range Interpretation
1-2 No fatigue
2.1-3 Mild fatigue
3.1-4 Moderate fatigue
4.1-5 Severe fatigue
5.1-7 Very severe fatigue

So, if your FSS score falls within the range of 1-2, congratulations! You’re not experiencing any fatigue at all. But if your FSS score falls within the range of 5.1-7, it’s time to take a closer look at what might be causing your fatigue.

Examples of FSS Calculations

Let’s take a look at some examples of FSS calculations for different individuals:

Name Age Gender Item 1 Item 2 Item 3 Item 4 Item 5 Total Score FSS Interpretation
John 35 Male 2 3 2 1 2 10 Mild fatigue
Jane 28 Female 4 5 4 4 5 22 Severe fatigue

As you can see, John’s FSS score falls within the range of 2.1-3, indicating mild fatigue. Jane’s FSS score, on the other hand, falls within the range of 5.1-7, indicating very severe fatigue.

Methods of FSS Calculation

There are several different methods for calculating FSS, each with its own advantages and disadvantages. Here are the most common methods:

Method Advantage Disadvantage Accuracy
Self-reported questionnaire Easy to administer Subjectivity Moderate
Objective measures (e.g., actigraphy) Objective data Expensive equipment High
Biomarker analysis Objective data Invasive High

The most common method for calculating FSS is the self-reported questionnaire. This method is easy to administer and is relatively inexpensive. However, it is also subject to bias, as the results are based on the individual’s perception of their own fatigue.

Objective measures, such as actigraphy (monitoring physical activity) or biomarker analysis (measuring changes in blood chemistry), provide more objective data but are often more expensive and invasive.

Evolution of FSS Calculation

The FSS has been around since 1987 and has evolved over time to become a widely used tool for measuring fatigue. Here’s a brief timeline of its development:

Year Development
1987 Development of the FSS
1995 Validation of FSS in MS patients
2002 Use of FSS in chronic fatigue syndrome patients

Limitations of FSS Calculation Accuracy

While the FSS is a useful tool for measuring fatigue, it does have some limitations. Here are some of the main limitations:

  1. Subjectivity of self-reporting: The FSS relies on the individual’s perception of their own fatigue, which can be subjective and may not accurately reflect their actual level of fatigue.
  2. Fatigue is a subjective experience: Fatigue is a complex symptom that can be caused by a variety of factors, including stress, illness, and lack of sleep. It can be difficult to accurately measure and quantify.
  3. Lack of standardization in administration of FSS: There is no standard protocol for administering the FSS, which can lead to inconsistencies in the results.

Alternative Methods for Measuring FSS Calculation

If you’re looking for alternative methods for measuring fatigue, there are several options available. Here are some of the most common methods:

Method Pros Cons
Epworth Sleepiness Scale Easy to administer Limited to daytime sleepiness
Visual Analog Scale (VAS) Simple Subjective
Fatigue Assessment Instrument (FAI) Validated in various medical conditions Lengthy

The Epworth Sleepiness Scale is a simple questionnaire that asks you to rate your level of sleepiness during the day. The Visual Analog Scale (VAS) is a simple tool that asks you to rate your level of fatigue on a scale of 1-10. The Fatigue Assessment Instrument (FAI) is a more comprehensive questionnaire that asks about a variety of factors that can contribute to fatigue.


  1. What is the Fatigue Severity Scale (FSS)? The FSS is a self-reported questionnaire used to measure the severity of fatigue in individuals.
  2. How do I calculate my FSS score? To calculate your FSS score, add up your responses to each item and divide by the total number of items.
  3. What is a good FSS score? A score of 1-2 indicates no fatigue, while a score of 5.1-7 indicates very severe fatigue.
  4. What are the limitations of FSS? Limitations of FSS include subjectivity of self-reporting, the subjective nature of fatigue, and lack of standardization in administration.
  5. What are some alternative methods for measuring fatigue? Alternative methods include the Epworth Sleepiness Scale, Visual Analog Scale (VAS), and the Fatigue Assessment Instrument (FAI).
  6. Can FSS be used to diagnose medical conditions? FSS can be used as an assessment tool in medical conditions that involve fatigue, but it is not a diagnostic tool.
  7. Is FSS a reliable measure of fatigue? FSS has been validated in a variety of medical conditions, but like any self-reported questionnaire, it is subject to bias.
  8. What is the difference between FSS and fatigue severity index? The fatigue severity index is a similar self-reported questionnaire used to measure fatigue, but it has a different scoring system and fewer items.
  9. How is FSS used in research? FSS is often used as an outcome measure in clinical trials and research studies involving fatigue.
  10. Can FSS be used in healthy individuals? Yes, FSS can be used in healthy individuals to measure their level of fatigue.


  1. National Multiple Sclerosis Society. (n.d.). Fatigue Severity Scale. https://www.nationalmssociety.org/nationalmssociety/media/msnationalfiles/brochures/10-2-3-3-Fatigue-Severity-Scale.pdf
  2. Johns, M. W. (1991). A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep, 14(6), 540-545.
  3. Kos, D., Kerckhofs, E., Nagels, G., D’Hooghe, M. B., & Ilsbroukx, S. (2006). Origin of fatigue in multiple sclerosis: review of the literature. Neurorehabilitation and neural repair, 20(1), 1-10.