Resting Metabolic Rate (Cunningham)
RMR from lean body mass via the Cunningham equation
Reviewed by the Nutricity editorial teamLast updated:
Calculator
How it is calculated
The Cunningham equation is:
RMR = 500 + 22 × lean body mass (kg)
Lean mass is derived from weight and body fat percentage. Because it is based on metabolically active tissue rather than just weight, it can be more appropriate for muscular individuals than some BMR formulas.
How to interpret the result
The result is an estimate of the calories you would burn at complete rest in 24 hours. Compare it with BMR estimates from Mifflin-St Jeor or Harris-Benedict. Differences reflect the different assumptions each formula makes.
How to use it
Use RMR as the base for daily energy needs; total expenditure depends on activity. See the TDEE calculator and the body fat % tool. For weight goals, pair with the calorie deficit/surplus calculator.
Limitations
- It requires a reliable body fat % estimate.
- Like all equations, it is an estimate with individual variation.
- Clinical conditions and medications can alter resting metabolism.
Related tools
Frequently asked questions
What is the difference between RMR and BMR?
RMR is resting metabolic rate, measured under relaxed conditions; BMR is basal metabolic rate, measured under stricter conditions. The values are close in practice.
Why does this need body fat %?
The Cunningham equation uses lean body mass, which is calculated from weight and body fat percentage. Lean tissue is the main driver of resting energy use.
Where can I get my body fat %?
You can estimate it with the <a href='/en/tools/body-fat'>body fat % calculator</a> or with methods such as DEXA, skinfolds or bioimpedance.