What is a normal FSS score?

In the original validation study, healthy controls had a mean FSS score of approximately 2.3. A score of 4 or above is the most widely used threshold for clinically meaningful fatigue.

What does an FSS score above 5 mean?

Scores above 5 are consistent with clinically meaningful fatigue as seen in ME/CFS, multiple sclerosis, and post-viral fatigue in published research. Discuss your results with your doctor.

Fatigue Severity Scale (FSS): free online questionnaire with scoring

Fatigue Severity Scale

FSS: Self-Report Fatigue Questionnaire

The Fatigue Severity Scale (FSS) is a 9-item questionnaire that measures the impact of fatigue on daily functioning. It was developed by Krupp and colleagues in 1989 and has become one of the most widely used fatigue instruments in clinical research and practice. Each item is a statement about fatigue, and you rate your agreement on a scale from 1 (strongly disagree) to 7 (strongly agree). Your score is the mean of all nine items.

The FSS does not measure how tired you feel in the moment. Instead, it captures how much fatigue interferes with your life over the preceding week: your motivation, exercise capacity, ability to carry out duties, and physical functioning. This makes it particularly useful for people with post-viral conditions, ME/CFS, and other chronic illnesses where fatigue is persistent and functionally limiting rather than simply a feeling of tiredness.

The FSS has been validated in multiple populations including multiple sclerosis, systemic lupus erythematosus, ME/CFS, and post-viral fatigue. It is referenced in major long COVID research studies and is one of the instruments used in the NIH RECOVER programme.

This is a free, interactive version. Complete it below and receive your score immediately. No sign-up or email is required.

This is not a diagnostic tool. Your score reflects self-reported fatigue impact and does not constitute a diagnosis of any condition. Discuss results with your doctor. Based on: Krupp LB, LaRocca NG, Muir-Nash J, Steinberg AD. The fatigue severity scale. Application to patients with multiple sclerosis and systemic lupus erythematosus. Arch Neurol. 1989;46(10):1121–1123.

Your FSS score

— out of 7

Item breakdown

Statement	Your rating
Mean score

Understanding your score

The FSS produces a mean score between 1 and 7. Higher scores indicate that fatigue has a greater impact on your daily functioning.

In the original validation study, healthy controls had a mean score of approximately 2.3, while patients with MS and lupus had mean scores of around 4.7 and 4.6 respectively. In long COVID research, mean FSS scores above 5 are commonly reported.

A score of 4 or above is the most widely used threshold for clinically meaningful fatigue, though interpretation depends on context.

The FSS is most useful when tracked over time. A change of 0.5 or more in the mean score is generally considered clinically meaningful. If you are testing an intervention or tracking your condition, completing the FSS at regular intervals (such as monthly) can give you a structured record of whether your functional fatigue is improving, stable, or worsening.

This score reflects the impact of fatigue on your daily life as you have reported it. It is not a diagnosis of any condition. Discuss your results with your doctor.