Fatigue Severity Scale Calculator

The FSS consists of nine distinct statements that assess various dimensions of fatigue, ranging from physical exertion to interference with work and social activities. Respondents rate each item on a Likert scale from 1 (strongly disagree) to 7 (strongly agree). The final overall score is calculated by finding the arithmetic mean of all nine responses. The mathematical equation is expressed as: Scale = (Item 1 + Item 2 + Item 3 + Item 4 + Item 5 + Item 6 + Item 7 + Item 8 + Item 9) / 9. The resulting average score ranges between 1.0 and 7.0, where higher numbers indicate a greater severity of fatigue.

Imagine a patient completing the nine-item fatigue questionnaire during a routine clinical check-in. They rate each statement as follows: Item 1 = 5, Item 2 = 6, Item 3 = 4, Item 4 = 5, Item 5 = 6, Item 6 = 5, Item 7 = 4, Item 8 = 6, and Item 9 = 5. To find the final Fatigue Severity Scale score, we sum all individual item values: 5 + 6 + 4 + 5 + 6 + 5 + 4 + 6 + 5 = 46. Next, we divide this cumulative total by the number of items (9). Therefore, 46 divided by 9 yields an average score of approximately 5.11. This elevated result indicates significant fatigue that likely interferes with normal daily routines, prompting a deeper investigation into underlying causes.

When completing the FSS questionnaire, try to evaluate your average experience over the past week rather than focusing solely on today's energy levels or a single bad night of sleep. Be honest and consistent in your scoring to ensure the resulting metric accurately reflects your functional capacity over time. Share your calculated score with a qualified healthcare professional to discuss targeted diagnostic tests or lifestyle interventions if chronic tiredness is impairing your quality of life.