The best measure of whether or not you are in shape is not necessarily your weight. With daily fluctuations from water retention or water loss through diuretics (alcohol and coffee), the best way to gauge how fit you are is by calculating your body fat. Unlike men, women have a few more calculations to make in order to get an accurate reading.
Get on the scale and weigh yourself. Write down this number.
Take Measurements. For women, there are four measurements needed to obtain an accurate number. First, measure your wrist circumference at its widest point. Then measure your waist circumference around your belly button. Next, measure your hip circumference at its widest point. Finally, measure your forearm circumference at its widest point.
Perform the following calculations: a) Multiply your body weight by .732. Write down this number. b) Add the above result to 8.987. Write down this number. c) Divide your wrist circumference by 3.14. Write down this number d) Multiply your waist measurement by .157. Write down this number. e) Multiply your hip measurement by .249. Write down this number. f) Multiply your forearm measurement by .434. Write down this number.
From Step 3, add results b + c. This will give you a new measurement which we will call g. Subtract d-f. This will give you a new measurement which we will call h. Now subtract e-h. This will give you a new result which we will call i. Add f+i and this will give you result j, or your lean body mass.
From Step 4, subtract j-a. Take that number and multiply it by 100. Finally divide that number by your total body weight. This number is your body fat percentage. You can also use convenient online body fat calculators like the one at LiveSTRONG.com.