You’re busy. We get that. With work, family, and friends, you can’t always exercise for one hour, several times a week, like you’re supposed to. Sometimes you just have to get in and get out.

But if you have only 20 minutes to pump iron, a few biceps curls and a quick jog won’t cut it—you need a workout that hits the whole body and burns as many calories as possible.

Here are six workouts that melt fat in under 20 minutes. Note: If you’re still standing by the end of these routines, you’re doing them wrong.