Well again, no one can tell you for sure. In *general* .. if you are
walking at a brisk pace (say 3.5 miles per hour or faster), you can estimate you'll burn 130
calories a mile or so. But again, that doesn't take into account your
heart rate or anything like that.
For most people (and again this is a very general estimate), moderate intensity
cardio (like brisk
walking) will burn anywhere from 300 to 500
calories per hour. And again, that's very general and doesn't take into account your
heart rate or general level of
fitness and so forth.
Any exercise you do that gets your
heart rate elevated for 20-30 minutes is going to help you lose weight, but
walking and exercise alone won't do it. The most important part of losing
fat is what you eat. You can walk until you fall over, but if you're eating non-nutritious food or too much food, you won't lose
fat.
So you need to make sure that you balance proper eating with your
walking.