For many people burning calories is the main reason for exercising. Besides the calories burned during the workout itself, you may have heard that the metabolism stays elevated afterwards, continuing to burn more calories than it would have otherwise.
Important to note though is that how the exercise is done and the type of exercise matter quite a lot. Any exercise will have some effect, but instensity is the key to getting a high EPOC(excess post-exercise oxygen consumption, a measure of calories burned.)
A 30 minute cardio session at 60% of a typical VO2 max(volume of oxygen, a measure of intensity) has a modest "afterburn" of about 16 calories, but at 70% VO2 max an extra 34 calories are burned after the exercise. The extra intensity more than doubles the calories burned afterward. However with HIIT(high intensity interval training, aka HIT for short) in approximately the same amount of time the extra calories burned is 73, more than double again.
The max EPOC is from weight lifting though. That means weights near your capacity, and lifts like squats that engage the entire body(same as functional strength training.) Twenty bicep curls won't do it, it's got to be as many muscles as possible engaged at once, and loads heavy enough you can't possibly do more than 10 in a row. Here the equivalent post-workout calories burned can exceed 700! The duration of the raised metabolism lasts much longer as well. More moderate weight training will still be superior to traditional cardio, but lift heavy if EPOC is your goal.
Here I'll point to my source for these numbers- Scott Stevenson, who wrote this excellent article on the topic: Discover the Afterburn
The summary: Steady cardio exercise burns calories while you do it and only a little after, HIT is much better, and hardcore weight training burns the most post-exercise calories.