# Fatigue Severity Scale Calculator (FSS) URL: https://speedycalculator.com/calculators/health/fatigue-severity-scale/ Last updated: 2026-10-30 > The fatigue severity scale calculator scores nine statements about how fatigue affects your motivation, activity and daily life, each rated 1–7, and tells you whether the average indicates significant fatigue. ## Inputs - 1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree) - 2. Exercise brings on my fatigue (1 strongly disagree – 7 strongly agree) - 3. I am easily fatigued (1 strongly disagree – 7 strongly agree) - 4. Fatigue interferes with my physical functioning (1 strongly disagree – 7 strongly agree) - 5. Fatigue causes frequent problems for me (1 strongly disagree – 7 strongly agree) - 6. My fatigue prevents sustained physical functioning (1 strongly disagree – 7 strongly agree) - 7. Fatigue interferes with carrying out certain duties and responsibilities (1 strongly disagree – 7 strongly agree) - 8. Fatigue is among my three most disabling symptoms (1 strongly disagree – 7 strongly agree) - 9. Fatigue interferes with my work, family or social life (1 strongly disagree – 7 strongly agree) ## Results - Mean FSS score - Total score ## Formula ``` Score = sum of the points for each item ``` ## Explanation The FSS was developed in 1989 for multiple sclerosis and lupus and is now used in many conditions, including long COVID and chronic fatigue syndrome. An average score of 4 or more (total 36 or more) suggests problematic fatigue. ### How to use the Fatigue Severity Scale Calculator - **1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree)** - **2. Exercise brings on my fatigue (1 strongly disagree – 7 strongly agree)** - **3. I am easily fatigued (1 strongly disagree – 7 strongly agree)** - **4. Fatigue interferes with my physical functioning (1 strongly disagree – 7 strongly agree)** - **5. Fatigue causes frequent problems for me (1 strongly disagree – 7 strongly agree)** - **6. My fatigue prevents sustained physical functioning (1 strongly disagree – 7 strongly agree)** - **7. Fatigue interferes with carrying out certain duties and responsibilities (1 strongly disagree – 7 strongly agree)** - **8. Fatigue is among my three most disabling symptoms (1 strongly disagree – 7 strongly agree)** - **9. Fatigue interferes with my work, family or social life (1 strongly disagree – 7 strongly agree)** Results update as you type, and every field accepts the units shown in its menu. ### How it works Each answer carries the points shown in the published score. The calculator adds them up and maps the total to the published interpretation. ### Inputs explained FieldWhat to enter1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree)A number2. Exercise brings on my fatigue (1 strongly disagree – 7 strongly agree)A number3. I am easily fatigued (1 strongly disagree – 7 strongly agree)A number4. Fatigue interferes with my physical functioning (1 strongly disagree – 7 strongly agree)A number5. Fatigue causes frequent problems for me (1 strongly disagree – 7 strongly agree)A number6. My fatigue prevents sustained physical functioning (1 strongly disagree – 7 strongly agree)A number7. Fatigue interferes with carrying out certain duties and responsibilities (1 strongly disagree – 7 strongly agree)A number8. Fatigue is among my three most disabling symptoms (1 strongly disagree – 7 strongly agree)A number9. Fatigue interferes with my work, family or social life (1 strongly disagree – 7 strongly agree)A number ### What each result means - **Mean FSS score** = ([1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree)] + [2. Exercise brings on my fatigue (1 strongly disagree – 7 strongly agree)] + [3. I am easily fatigued (1 strongly disagree – 7 strongly agree)] + [4. Fatigue interferes with my physical functioning (1 strongly disagree – 7 strongly agree)] + [5. Fatigue causes frequent problems for me (1 strongly disagree – 7 strongly agree)] + [6. My fatigue prevents sustained physical functioning (1 strongly disagree – 7 strongly agree)] + [7. Fatigue interferes with carrying out certain duties and responsibilities (1 strongly disagree – 7 strongly agree)] + [8. Fatigue is among my three most disabling symptoms (1 strongly disagree – 7 strongly agree)] + [9. Fatigue interferes with my work, family or social life (1 strongly disagree – 7 strongly agree)])÷9 - **Total score** = [1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree)] + [2. Exercise brings on my fatigue (1 strongly disagree – 7 strongly agree)] + [3. I am easily fatigued (1 strongly disagree – 7 strongly agree)] + [4. Fatigue interferes with my physical functioning (1 strongly disagree – 7 strongly agree)] + [5. Fatigue causes frequent problems for me (1 strongly disagree – 7 strongly agree)] + [6. My fatigue prevents sustained physical functioning (1 strongly disagree – 7 strongly agree)] + [7. Fatigue interferes with carrying out certain duties and responsibilities (1 strongly disagree – 7 strongly agree)] + [8. Fatigue is among my three most disabling symptoms (1 strongly disagree – 7 strongly agree)] + [9. Fatigue interferes with my work, family or social life (1 strongly disagree – 7 strongly agree)] ### Example values How the main result changes when **1. My motivation is lower when I am fatigued** changes and everything else stays at the example values above: 1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree)Mean FSS score23.7833.894454.1164.22 *Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.* ## Worked example Inputs — 1. My motivation is lower when I am fatigued (1 strongly disagree – 7 strongly agree): 4; 2. Exercise brings on my fatigue (1 strongly disagree – 7 strongly agree): 4; 3. I am easily fatigued (1 strongly disagree – 7 strongly agree): 4; 4. Fatigue interferes with my physical functioning (1 strongly disagree – 7 strongly agree): 4; 5. Fatigue causes frequent problems for me (1 strongly disagree – 7 strongly agree): 4; 6. My fatigue prevents sustained physical functioning (1 strongly disagree – 7 strongly agree): 4; 7. Fatigue interferes with carrying out certain duties and responsibilities (1 strongly disagree – 7 strongly agree): 4; 8. Fatigue is among my three most disabling symptoms (1 strongly disagree – 7 strongly agree): 4; 9. Fatigue interferes with my work, family or social life (1 strongly disagree – 7 strongly agree): 4. Results — **Mean FSS score = 4**; Total score = 36 / 63. ## Key terms - **FSS**: Fatigue Severity Scale. ## FAQ **What FSS score means significant fatigue?** An average of 4 or more. **Which period should I think about?** The past week. **What can cause fatigue?** Sleep problems, anaemia, thyroid disease, depression, medicines and many chronic illnesses. ## Sources - [Krupp LB et al. The fatigue severity scale. Arch Neurol, 1989](https://pubmed.ncbi.nlm.nih.gov/2803071/)