It's Free. Doing 300 crunches per day is impressive, but won't burn a notable number of calories. The sad news is, 100 crunches a day is not going to burn all that many calories. They do, however, strengthen your abs. ☺ EDIT: You also neglected to say for how long or what you weigh. Add cardio and other core work for a greater burn. I did a quick search for you and sit-ups are said to burn 3 - 5 calories a minute. Depending on your weight, intensity, and general activity level, the calories burned are going to vary. Crunches work on one specific muscle group and don't require big movements that result in a notable calorie burn. But crunches will definitely help you on your way to that six pack by developing strong abdominal muscles. What seems unanimous, however, is that you will burn between 15 and 40ish calories by doing 100 crunches. Period. You have to understand that to get a flat stomach its not all about how many crunches or how many sit ups a day you do, it’s about how much you are eating and just what you are eating. Burn calories for crunches and track with our workout tracker. To get rid of fat, you have to do exercises that burn calories and blast fat all over the body -- namely, cardio that gets your heart pumping. Bicycle crunches might be slightly more, but not a lot. Use the calories burned calculator below to see how many calories you burned during your workout. Burn calories for crunches and track with our workout tracker. How many calories will you burn doing 100 crunches a day? Try riding a bicycle if you want to burn calories (or jogging or swimming or aerobics or dancing get the picture). "How many bicycle crunches does it take to burn 1 calorie for a 100lb 27 year old female,?" So, in order to calculate how many calories do you burn doing 100 crunches, all you need is to multiply the number of calories you burn in a minute by 3.3, which is how many minutes it takes to perform 100 crunches. Find out how many calories you burn for Crunches. Use the calories burned calculator to calculate how many calories burned for crunches. The number of calories you burn while exercising is dependent on the exercise you do, your weight, and the time spent doing the exercise. That's not to say that bicycle crunches shouldn't be part of your routine, but they're just not the belly-blaster you thought they might be.