Understanding Your BMI



Some Salter scales use BIA (Bio Impedance Analysis) technology which passes a small electrical impulse through the body to distinguish fat from lean tissue. The electrical impulse cannot be felt and is perfectly safe. Contact with the body is made via stainless steel pads or a conductive film on the scale platform. This method simultaneously calculates your personal weight, body fat, total body water, BMI, Basal Metabolic Rate, bone mass and muscle mass, giving you a more accurate reading of your overall health and fitness.

CAUTION : Do not use BIA function if you have a pacemaker or other medical device fitted. If in doubt, consult your doctor.

Salter scales are for domestic use only. Pregnant women should only use the weight function.


The human body is made up of, amongst other things, a percentage of fat. This is vital for a healthy, functioning body - it cushions joints and protects vital organs, helps regulate body temperature, stores vitamins and helps the body sustain itself when food is scarce. However, too much body fat or indeed too little body fat can be damaging to your health. It is difficult to gauge how much body fat we have in our bodies simply by looking at ourselves in the mirror. This is why it is important to measure and monitor your body fat percentage. Body fat percentage gives you a better measure of fitness than weight alone - the composition of your weight loss could mean you are losing muscle mass rather than fat -you could still have a high percentage of fat even when a scale indicates 'normal weight'.



*Source: Derived from: HD McCarthy, TJ Cole,T Fry, SA Jebb and AM Prentice: "Body fat reference curves for children". International Journal of Obesity (2006) 30, 598-602.

**Source: Derived from: Dympna Gallagher, Steven B Heymsfield, Moonseong Heo, Susan A Jebb, Peter R Murgatroyd, and Voichi Sakamoto: "Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index1-3". Am J Clin Nulr 2000;72:694-701.

The Body Fat % ranges published are for guidance only. Professional medical guidance should always be sought before embarking on diet and exercise programs.


Body water is the single most important component of bodyweight. It represents over half of your total weight and almost two thirds of your lean body mass (predominantly muscle). Water performs a number of important roles in the body: All the cells in the body, whether in the skin, glands, muscles, brain or anywhere else, can only function properly if they have enough water. Water also plays a vital part in regulating the body's temperature balance, particularly through perspiration. The combination of your weight and fat measurement could appear to be 'normal' but your body hydration level could be insufficient for healthy living.