How to to determine your body fat percentage

My Views on Body Fat Measuring Devices

Calculators / Formulas

All the "magical" calculators out there are utterly pointless. It doesn't include the important variable, muscle mass. They are also based on average water levels and don't forget people store fat differently. Don't waste your time with these calculators, you won't find any on this site :)

Body Fat measuring scales.

Electronic body fat measuring devices use the Bioelectrical Impedance Analysis (BIA) method. Better than all the calculators and formulas out there, but still very inaccurate. Many factors influence readings on these machines, such as time of day, water / hydration levels, position and density of your skin. The cheap ones (less than £15) also don't include muscle mass and bone density (no, don't use the "I'm just big boned excuse"). The brand Tanita is probably the most accurate but I wouldn't base anything on the result from one of these machines. Professionals tend to use professional devices costing in the region of £500 so you really do get what you pay for.

Calipers / Skinfold

Getting closer... calipers for those who don't know it is a manual device to measure your skin fold. They give a good and accurate reading but there margin for error depending on who measured and what sites on your body they measured you from. When using calipers, get someone to do it for you and use the same person to do all the measuring. That way you'll not have inconsistencies depending on who did the measurements.

Under Water Weighing / Hydro densitometry Weighing

Based on the fact that muscle and bone is denser than water and fat is isn't we can measure the person's volume of water expelled when the person is submerged and the weight of that person before weighing and weight underwater. A very accurate measurement of body fat, but not practical. If you're interested in this method of weighing then you may wish to contact some of the bigger uni's.

MRI Scanning (Magnetic Resonance Imaging)

The most accurate method, the most expensive and the most impractical. A MRI scan will give you detailed feedback about your fat internal fat surrounding organs. The magnetic field gets feedback from water and fat moulacles

Conclusion?

Use calipers but don't get hung up on numbers. If you really think about it, how important is it to know your body fat levels? Keep it simple and mainly just use the mirror. Sounds obvious, but you should know when you're carrying any unwanted amount of body fat.