You can always go to a standard table of calories with your height and weight to estimate how many calories you burn daily, but if you are willing to pull out your calculator or your keyboard, you can more accurately figure it on your own, using your individual characteristics and habits.
Calculate Calories Burned in a Day
Step 1
Find your body fat percentage. There are several ways you can do this: you can have it measured with calipers at a gym or by a nutritionist, you can have an underwater weighing, or you could estimate it with an online body fat estimator.
Step 2
Determine your fat-free mass (FFM). Multiply your body weight in pounds by one minus your body fat percentage: FFM = body weight in pounds x (1 - body fat percentage). For example, if you weigh 160 lbs. and have a body fat percentage of 23, your FFM would be 160 x (1 - 0.23) = 123 lbs.
Step 3
Calculate your resting metabolic rate (RMR), which is your resting calorie usage over 24 hours. There are several ways to do this, but one of the simplest is with the J.J. Cunningham equation from the "American Journal of Clinical Nutrition." This equation reads RMR = 370 + 9.81 x FFM. Using our 160 lb. example person, that gives RMR = 370 + 9.81 x 123 = 1,577 calories.
Step 4
Convert that daily value into an hourly one by dividing by 24: hourly RMR = 1,577 / 24 = 66 calories per hour.
Step 5
Look up the metabolic equivalent task (MET) values for all your daily activities. You will find these numbers in "The Compendium of Physical Activities," which can be found at the University of South Carolina School of Public Health (see Resources). Include all your activities, from sleeping to tennis to doing laundry. Here are some sample activities from the compendium: playing ping pong, MET = 4; laying sod, MET = 5 ; knitting, MET = 1.5.
Step 6
Calculate the caloric burn of these activities. Multiply together your hourly RMR, the hours you spent in the activity and the MET value of the activity to give the calories burned for each activity. For example, suppose our 160-lb. person played ping pong for 90 minutes. That would be 66 calories/hour x 1.5 hours x 4 MET = 396 calories. Keep in mind that those 396 calories are the total burned in that time, not an additional amount to the RMR calories.
Step 7
Combine all the activities for the day. Here is an example for our 160-lb. friend: sleeping, 66 x 8 hours x 0.9 MET = 475; showering and grooming, 66 x 2 hours x 2 MET = 264; working at a desk, 66 x 7 hours x 1.8 MET = 832; doing household chores, 66 x 2 hours x 2.5 MET = 330; playing ping pong, 66 x 1.5 hours x 4 MET = 396; reading, talking and eating, 66 x 2.5 hours x 1.5 MET = 248; watching TV in bed, 66 x 1 hour x 1.0 MET = 66. The 24 hours add up to 2,611 calories burned for the whole day.
Tips and Warnings
- You can skip the first few steps in which you calculate RMR by using an online RMR calculator instead (see Resources).
- This process is based on research averages, so it may not work perfectly for people with unusual circumstances, like metabolic illnesses or who are elite athletes. If you gain or lose a lot of weight, you will of course need to return to this process and recalculate.
Things You'll Need
- Table of metabolic equivalent tasks
- Calculator
- Your body fat percentage
- Your body weight in pounds
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