A 160-pound person needs to run 4.13 miles to burn 500 calories. Every pound lighter than 160 pounds burns about 2.25 calories less per pound, and every pound heavier than 160 pounds burns about 2.25 calories per pound more for the same distance.
The amount of calories burned by an individual while running is a function of weight and pace. A faster runner burns more calories over the same distance, but spends less time doing so than a slower runner who weighs the same. The formula does not work evenly below 150 pounds, but it is safe to assume at least 100 calories per mile burned for a person weighing over 100 pounds. Experience also matters, as a more efficient runner burns less calories for the same distance than the less experienced athlete.