When you want to know how many calories you burn daily, you can either rely on standard tables, or you can more accurately calculate it on your own, using your individual characteristics and lifestyle. This can give you a personalized estimate of the calories you burn daily, rather than a generic value that might not apply to your situation.
Estimate Your Daily Calorie Burn
Step 1
Find out how many kilograms you weigh. If you know already, skip this step, but otherwise, take your weight in pounds and divide by 2.2. Here is an example: if you weigh 128 pounds, the calculation would be 128 / 2.2 = 58 kilograms.
Step 2
Determine the part of your total from Step 1 that is fat-free mass, or FFM, only. Take 1 minus your body fat percentage, and multiply it by your weight in kilograms, written as FFM = (1 - body fat percentage) x body weight in kilograms. If we use the example above with the 58 kilograms, and use a body fat percentage of 22%, the FFM would be (1 - 0.22) x 58 = 45 kilograms.
Step 3
Find the calories you burn at rest in 24 hours, called your resting metabolic rate, or RMR. You can do this a number of ways, but probably the simplest is using the J.J. Cunningham equation, which reads, RMR = 370 + 21.6 x FFM. With our 58 kilogram person above, that would be RMR = 370 + 21.6 x 45 = 1,342 calories.
Step 4
Turn your daily RMR into an hourly RMR by dividing by 24. Continuing our example, that would be: hourly RMR = 1,342 / 24 = 56 calories per hour.
Step 5
Consult the \"The Compendium of Physical Activities\" to find the metabolic equivalent task values, or MET, for all your daily activities. You can find this document at the University of South Carolina School of Public Health website, which did the original research. Be sure to include all activities, even eating, sleeping, and \"doing nothing.\" As an example, these are some MET values from the Compendium: speed skating, MET = 15; laying sod, MET = 5 ; standing in line, MET = 1.2.
Step 6
Compute the number of calories you burned in these activities. Take the product of the MET value, your hourly RMR and the hours you performed the activity. For example, if our 58-kilogram person spent two hours laying sod, she would have burned 5 MET x 56 calories/hour x 2 hours = 560 calories. Note that 560 calories is the total calories she burned in those two hours, not in addition to the RMR calories.
Step 7
Sum the activity calories for all the activities performed in your day. Consider the example of our 58-kilogram person's day: <br />Sleeping, 0.9 MET x 56 x 8 hours = 403; <br />Showering and grooming, 2 MET x 56 x 2 hours = 224<br />GO<br />Working at a desk, 1.8 MET x 56 x 7 hours = 706; <br />Doing household chores, 2.5 MET x 56 x 2 hours = 280<br />GO<br />Laying sod, 5 MET x 56 x 2 hours = 560<br />GO<br />Reading, talking, and eating, 1.5 MET x 56 x 2 hours = 168<br />GO<br />Watching TV in bed, 1.0 MET x 56 x 1 hour = 56.<br /><br />The 24 hours add up to 2,397 calories burned for the whole day.
Tips and Warnings
- If you don't have your body fat percentage, a personal trainer or nutritionist can give it to you, or you can use an online calculator to estimate it for you.<br />You can skip the RMR calculation step by using an online RMR calculator instead.
- The calculations and equations in this process all come from statistical averages and confidence intervals, so they won't be terribly accurate in unusual situations, such as for people with metabolic illnesses like thyroid disease or diabetes, or for those who are unusually fit.<br />If you are losing or gaining weight steadily from diet, exercise or growth, you will need to periodically recalculate your values.<br />Finally, if you make big changes to your calorie intake or activity level, expect your body to adapt to those changes, so that your initial results may not hold up over time.
Things You'll Need
- Your body fat percentage<br />Your body weight in pounds or kilograms<br />Table of metabolic equivalent tasks<br />Calculator
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