How to calculate your Body Fat Percentage

I’ve mentioned before how tracking weight can be misleading, given that you’re weighing not only fat, but also muscle, bone, organs, fluids and more.

Another metric people use to track progress is body fat percentage. 

This is more useful since it’s, in theory, only measuring your body fat, so any changes do mean that you’ve changed the amount of body fat you have (as a percentage of your total bodyweight).

Whilst it’s a bit backward that we measure weight in kilos/pounds etc and bodyfat as a percentage, it is still a great way to track progress.

There are a number of ways to measure body fat percentage and you have to be very careful about which you use and how seriously you take it.

Bioelectrical Impedance (handheld monitors, scales that measure body fat, and similar devices that you simply hold, stand on, or attach to your body in some way) are incredibly inaccurate and can be affected by many factors – hydration levels, if you have any creams/lotions on your hands/feet, even how you are standing when testing. If you use these, don’t take the reading as being completely accurate, and at the very least, use the exact same equipment every time, and make sure the conditions are the same.

Skinfold/Caliper Testing. This is where someone (hopefully trained in the use of skinfold calipers) takes a number of measurements at certain points around your body and uses a calculation to determine your body fat percentage. This can be more accurate than the handheld devices, but depends completely on the competence and skill of the person taking the measurements. It’s also quite intrusive, having someone pinch your fat rolls and measure them! Again, be sure that your practitioner is well accustomed to taking these measurements to reduce the margin of error.

DEXA Scan is considered the gold standard and most accurate way of measuring body fat, but this is an expensive option, and will likely require some travelling to somewhere that offers it. By all means use this method if it is within your means.

The last method I’m going to talk about here is called the Navy Method, and I’ve found it to be a reasonably accurate method of measuring body fat percentage when a DEXA scan or skilled skinfold testing is not available or appropriate, and all you need to do it is a tape measure (and a helper).

To do this, you simply need to measure your navel, neck and height (for men), or your natural waist, hips, neck and height (for women).

Once you have these measurements you can enter them into a calculator that will give you a reasonably accurate estimate of your body fat percentage. A simple google search for “navy method body fat calculator” will give you plenty of options.

I find this to be a good way of measuring body fat without needless expense or intrusion.

Take all measurements 3 times to ensure better accuracy, and you can use the results to track progress and help you decide if you need to make any adjustments to your diet or training plan.


Remember though, if you aren't getting the results you want, be honest with yourself and ensure that you are sticking to your plan before you change it!

Most people, if they're being honest, probably aren't sticking to the plan, yet wonder why it isn't working. If you're (honestly) sticking to your plan at least 80% of the time and still aren't getting results, then adjust the plan; but if you're simply not sticking to it, work harder at that before you change anything.

The only caveat to this is if you're trying to follow a plan that's too strict and you can't follow it. Then you'll need to adjust it to something that is achievable for you.