How to use the fatigue duration calculator
Enter the date your fatigue began and a reference date. The page counts the difference in days and converts it to weeks and calendar months. Weeks divide by seven. Months land on the same day of the month, clamped to the last day where that date does not exist, so one month after January 31 is February 29 in a leap year such as 2024 and February 28 otherwise.
Why there is no score
No published rule exists for weighting sleep, stress and symptom counts into a fatigue score or index. Inventing the weights produces a figure that looks precise and rests on nothing. The low results are the worse half: a low number from a score of unverified performance reassures people who do have a problem, and delays the appointment. So this page counts how long it has been and nothing else.
For duration, the reference point is the 2015 Institute of Medicine (IOM) criteria for ME/CFS, which the CDC uses: fatigue that substantially reduces activity and lasts 6 months or more, together with post-exertional malaise, unrefreshing sleep, and either cognitive impairment or orthostatic intolerance. This page checks only the 6-month mark and judges none of the other features. If fatigue is dragging on, do not wait for six months to have the cause looked into. Weight loss, fever, breathlessness, or being unable to get through the day are reasons to be seen regardless of the duration. A short figure here does not mean there is no cause (as of October 2026).
Frequently Asked Questions
Because no published rule weights sleep, stress and symptoms into one. A low result from a score whose performance was never verified delays care, which makes it worse than no score.
The criteria the CDC uses for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), from the Institute of Medicine (IOM) in 2015, require substantial fatigue lasting 6 months or more, and the page shows where you stand against that 6-month mark. Those criteria also require post-exertional malaise, unrefreshing sleep, and cognitive impairment or orthostatic intolerance, with other causes ruled out by a clinician, so duration alone is not a diagnosis.
As calendar months. The same day of the month counts as one month, clamped to the last day when that date does not exist, so one month after January 31 is the last day of February.