One common question that we receive almost daily is, “how do I determine my metabolic rate?” In today’s post, I’ll explain a few simple methods for calculating your resting metabolism, i.e. how many calories you burn while at rest. At the end of this post you will find a resting metabolic rate calculator to figure your RMR out quickly and easily.
In my practice, I use a system called “indirect calorimetry” to evaluate resting metabolic rate in my clients. This method is considered the gold standard in clinical practice for assessing metabolic rate. The most accurate way to evaluate your metabolism is by finding a practitioner who can perform this simple test on you. If you’re unable to find someone to test your metabolism using indirect calorimetry, then you can estimate your metabolism using one of a number of resting metabolic rate calculator formulas.
Three Simple Resting Metabolic Rate Calculator Formulas
Method 1: Assume That You’re Average
According to exercise physiologists, William Mcardle and Frank Katch, the average number of calories needed to maintain weight for men is 2700-2900 calories and the average for women is 2000-2100 calories per day.
If you’re not significantly overweight, you can use these averages as a starting point, monitor your body’s response (i.e. do you lose weight), and then tweak the number until you are losing one-half to one pound a week. This method requires no complicated resting metabolic rate calculator, but may overgeneralize and thus provide results that may be too high or too low.
Method 2: The VERY Simple Resting Metabolic Rate Calculator
This next method is commonly used because it is extremely easy to use and it accounts for weight.
For weight loss, simply multiply your weight in pounds by 12 or 13 calories
For weight maintenance, simply multiply your weight in pounds by 15 or 16 calories.
Generally, I recommend women use the lower number (12 for weight loss and 15 for weight maintenance) while men use the higher number (13 for weight loss and 16 for weight maintenance).
If you are significantly overweight, 300+ pounds, for example, this formula may not be a good estimation.
Method 3: The Complicated Resting Metabolic Rate Calculator
This next method is a bit more involved, but will likely give you a more accurate starting point. It uses a standard equation called the Harris Benedict Resting Metabolic Rate Calculator:
Men: BMR = 66 + (13.7 X wt in kg) + (5 X ht in cm) – (6.8 X age in years)
Women: BMR = 655 + (9.6 X wt in kg) + (1.8 X ht in cm) – (4.7 X age in years)
(1 inch = 2.54 cm and 1 kilogram = 2.2 lbs)
After you calculate your BMR (basal metabolic rate, i.e. the number of calories you burn if you laid still all day), you will need to account for your level of activity in an average day…after all, taking out the trash and buying groceries does burn calories. To accomplish this, multiply your BMR by the value below that corresponds to your activity level:
- Sedentary (little or no exercise, low daily activity i.e. desk job) = BMR X 1.2
- Mildly active (light exercise/sports 1-3 days/wk) = BMR X 1.375
- Moderately active (moderate exercise/sports 3-5 days/wk) = BMR X 1.55
- Very active (hard exercise/sports 6-7 days/wk) = BMR X 1.725
- Extremely Active (hard exercise/sports and you have a physical job or 2X day training, i.e marathon, competitive athlete)= BMR X 1.9
Although this formula takes a bit more work, it will provide a more accurate representation of your daily caloric burn.
What It All Means
In the end, it’s all just estimation. Even when you use the Complicated Method described above, you may still be off by 100-300 calories per day. Knowing this, always tweak your program to your results! If you calculated that you need 2900 calories per day and notice that you’re not losing weight on this program, then you may need to drop it by 100 calories and assess again in a couple of weeks. Likewise, if you find that you feel deprived, hungry, and lack energy, then you may need to increase the number of calories by 100 calories or more.
If you listen to the podcast, you know that I’m not a big fan of calorie counting as a long-term approach to weight loss. It certainly can be helpful in the beginning when you can’t trust your body’s hunger signals, but eventually you will need to transition into a lifestyle that isn’t reliant on counting every morsel of food. This requires an approach that teaches you to trust the body’s subtle signals by living a lifestyle that balances the metabolic hormones. Refer to the Cut the Fat Weight Loss Podcast for more details on such an approach and good luck!
For those who prefer to calorie count and want a simple resting metabolic rate calculator, simply input your numbers below and the calculator will show you your RMR. Remember to multiply it by your activity coefficient listed above under the “Complicated Resting Metabolic Rate Calculator”.