6MWD % Predicted Calculator (Enright & Sherrill)
Compare your 6-minute walk test distance to the age, sex, height, and weight-predicted norm using the Enright & Sherrill reference equation.
Reviewed by Rahul Singh, Health & Wellness Specialist
Formula
Male: Predicted = (7.57 x H) - (5.02 x A) - (1.76 x W) - 309 | Female: Predicted = (2.11 x H) - (2.29 x W) - (5.78 x A) + 667
Where H = height in centimeters, A = age in years, W = weight in kilograms. The lower limit of normal (LLN) is predicted minus 153 meters for males and predicted minus 139 meters for females. Percent predicted = (actual distance / predicted distance) x 100.
Worked Examples
Example 1: Male Patient with COPD
Problem:A 65-year-old male, 175 cm tall, weighing 80 kg, walks 380 meters in 6 minutes. Calculate the percent predicted 6MWD.
Solution:Predicted (male) = (7.57 x 175) - (5.02 x 65) - (1.76 x 80) - 309\n= 1324.75 - 326.3 - 140.8 - 309\n= 548.65 meters\nLLN = 548.65 - 153 = 395.65 meters\nPercent predicted = (380 / 548.65) x 100 = 69.3%\nInterpretation: Moderately reduced (below LLN of 395.65 m)
Result:Percent predicted: 69.3% | Moderately reduced functional capacity
Example 2: Female Patient Post-Cardiac Surgery
Problem:A 58-year-old female, 162 cm tall, weighing 68 kg, walks 420 meters in 6 minutes. Calculate the percent predicted 6MWD.
Solution:Predicted (female) = (2.11 x 162) - (2.29 x 68) - (5.78 x 58) + 667\n= 341.82 - 155.72 - 335.24 + 667\n= 517.86 meters\nLLN = 517.86 - 139 = 378.86 meters\nPercent predicted = (420 / 517.86) x 100 = 81.1%\nInterpretation: Mildly reduced (above LLN of 378.86 m)
Result:Percent predicted: 81.1% | Mildly reduced but above lower limit of normal
Frequently Asked Questions
What reference equations does this 6MWD calculator use?
6MWD % Predicted Calculator (Enright & Sherrill) uses the Enright and Sherrill (1998) reference equations, the most widely cited normative equations for the six-minute walk test. For males: predicted distance = (7.57 x height in cm) - (5.02 x age) - (1.76 x weight in kg) - 309 meters. For females: predicted distance = (2.11 x height in cm) - (2.29 x weight in kg) - (5.78 x age) + 667 meters. The lower limit of normal (LLN) is the predicted value minus 153 meters for males and minus 139 meters for females. These equations were derived from 290 healthy volunteers (117 men, 173 women) aged 40-80 in the original study published in the American Journal of Respiratory and Critical Care Medicine, and remain a standard reference cited across pulmonary and cardiac rehabilitation guidelines.
Why is my percent predicted 6MWD different from what my doctor calculated?
Several published reference equations exist for the 6MWD besides Enright and Sherrill (1998) — including Troosters et al. (1999, elderly Belgian cohort) and Casanova et al. (2011, seven-country pooled cohort, Eur Respir J) — and each uses slightly different coefficients for age, height, weight, and sex, so the same walk distance can produce a different predicted value and a different percent predicted depending on which equation a clinic uses. Studies that compare multiple reference equations side by side on the same patients consistently find the predicted distance can shift by tens of meters between formulas. If your clinic reports a different percent predicted, ask which reference equation they used, and treat the raw distance and the lower limit of normal (LLN) as the most stable numbers to track over time rather than the percentage alone.
How is the 6MWD used in clinical decision making?
The 6MWD guides decisions across several specialties. In COPD, a distance of 350 meters or less is associated with a higher risk of exacerbation, hospitalization, and mortality, and the test is a component of the BODE index used for prognosis. In idiopathic pulmonary fibrosis, a baseline below 250 meters is linked to roughly double the mortality risk, and a decline of more than 50 meters over 24 weeks is linked to triple the mortality risk. In heart failure, typical distances by NYHA class are approximately 400 m (Class II), 320 m (Class III), and 225 m (Class IV) (StatPearls, NCBI Bookshelf, 2024). A change of about 30 meters is generally considered the minimal clinically important difference (MCID) per ATS/ERS field walking test standards.
Does the 6MWD calculator need my weight and height, and why?
Yes — both the Enright and Sherrill equations require height and weight (plus age and sex) because taller people and lighter people tend to walk further in six minutes, all else equal, and the regression coefficients quantify exactly how much each factor shifts the predicted distance. Leaving out weight or height would make the predicted distance and percent predicted inaccurate, since the formula subtracts a weight term and adds a height term with specific published coefficients (see the formula above). Use your actual measured height and weight, not estimates, for the most accurate percent predicted result.
References
- Enright PL, Sherrill DL — Reference equations for the six-minute walk in healthy adults. Am J Respir Crit Care Med 1998;158:1384-1387
- ATS Statement: Guidelines for the Six-Minute Walk Test
- Casanova C, et al. — The 6-min walk distance in healthy subjects: reference standards from seven countries. Eur Respir J 2011;37:150-156
- Six-Minute Walk Test — clinical thresholds by condition and MCID. StatPearls, NCBI Bookshelf, 2024
Reviewed by Rahul Singh, Health & Wellness Specialist · Editorial policy