Run to Lose: This tool tells you how many calories a day you burn at rest. That figure is your basal metabolic rate, or the amount of your energy your body needs to maintain basic functions such as breathing, digestion, and brain activity.

for calculating how many calories you burn through running and other forms of exercise: Weight control is primarily a matter of calories in and calories out. Knowing your basal metabolic rate is part of keeping that energy balance where you want it.

Bear in mind that people of the same height, weight, and gender can have different basal metabolic rates. Some people are simply born with a more active “internal engine” that requires more calories. In addition, a fit 150-pound person is likely to have a higher basal metabolic rate than an unfit 150-pounder of the same height and gender, because the fit person probably has more muscle and less fat than the unfit person.

That said, the figure this tool provides gives you a (good) rough idea of your at-rest caloric needs, which is consistent from day to day. Add to that the calories you burn per day from running and other activities, and you get your overall calorie needs. With that figure, you can devise a The Runners World Editors, Not Sure What to Wear on a Run? This Tool Can Help.

Here’s our calories burned tool The Runners World Daily Calories Calculator.

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Health & Injuries: Fill in all of the fields below. You can enter your height in feet and inches, or centimeters, and you can enter your weight in pounds or kilograms. Use the whole number closest to your measurements. For example, if you stand 5 feet, 5.75 inches, enter 5 feet, 6 inches.

After entering all of the variables, hit “calculate.” The resulting figure is the amount of daily calories needed for basic bodily functions for someone of your age, gender, height, and weight.

[Related: Runner's World BMI Calculator]