One of the most common questions we receive in our email inbox is "how much should I weigh for my height and age?" In this article, we will explain the most common ways in which this can be worked out.
To determine how much you should weigh (your ideal body weight) several factors should be considered, including age, muscle-fat ratio, height, sex, and bone density.
Some health professionals suggest that calculating your Body Mass Index (BMI) is the best way to decide whether your body weight is ideal. Others say that BMI is faulty as it does not account for muscle mass and that waist-hip ratio is better.
One person's ideal body weight may be completely different from another's. If you compare yourself to family and friends you risk either aiming too high if you are surrounded by obese or overweight people, or too low if everyone around you works as fashion models.
Even comparing yourself with people outside your immediate surroundings may not work.
The levels of overweight and obesity in one country, such as the USA or UK, are much higher than in The Netherlands. So a Dutch person may aim for a lower ideal weight than an American if all he did was to compare himself to other people.
A recent study may have turned national guidelines on people’s ideal weight on its head. Researchers found that overweight people have a lower all-cause mortality risk compared to those of normal weight.
Is Body Mass Index (BMI) a good measure of your weight?
Your BMI is your weight in relation to your height.
BMI metric units: Your weight (kilograms) divided by the square of your height (meters)
e.g. Weight 80 kilograms. Height 1.8 meters.
1.82 meters = 3.24
80 divided by 3.24 = BMI 24.69.
Imperial units: Your weight (pounds) times 703, divided by the square of your height in inches.
e.g. Weight 190 pounds. Height 6 ft (72 inches)
722 = 5184
190 x 703 divided by 5184 = BMI 25.76
Health authorities worldwide mostly agree that:
People with a BMI of less than 18.5 are underweight.
A BMI of between 18.5 and 25 is ideal.
Somebody with a BMI between 25 and 30 is classed as overweight.
A person with a BMI over 30 is obese.
In some countries health authorities say the lower limit for BMI is 20, anything below it is underweight.
How to calculate Your BMI
To calculate your BMI you can use our metric BMI calculator below (requires Flash) or, alternatively, use our more comprehensive BMI Calculator.
What is the problem with BMI?
BMI is a very simple measurement which does not take into account the person's waist, chest or hip measurements. An Olympic 100 meters sprint champion may have a BMI higher than a couch potato of the same height. The couch potato may have a big belly, not much muscle and a lot of body fat on his hips, upper thighs, in his blood and other parts of his body. While the athlete will have a smaller waist, much less body fat, and most likely enjoy better health. According to a purely BMI criteria, the couch potato is healthier.
BMI does not take into account bone density (bone mass). A person with severe osteoporosis (very low bone density) may have a lower BMI than somebody else of the same height who is healthy, but the person with osteoporosis will have a larger waist, more body fat and weak bones.
Many experts criticize BMI as not generally useful in evaluation of health. It is at best a rough ballpark basic standard that may indicate population variations, but should not be used for individuals in health care.
Put simply: experts say that BMI underestimates the amount of body fat in overweight/obese people and overestimates it in lean or muscular people.
More information on BMI, together with imperial and metric BMI calculators, is available here.
Nick Trefethen, a Professor of Numerical Analysis at Oxford University's Mathematical Institute, has created what he believes to be a better, more accurate and relevant formula than the BMI one for deciding whether people are carrying too much fat. Humans do not grow equally in all three dimensions, he explains - the existing BMI formula presumes we do.
Waist-Hip Ratio (WHR)
A waist-hip measurement is the ratio of the circumference of your waist to that of your hips. You measure the smallest circumference of your waist, usually just above your belly button, and divide that total by the circumference of your hip at its widest part.
If a woman's waist is 28 inches and her hips are 36 inches, her WHR is 28 divided by 36 = 0.77. Below is a breakdown of WHR linked to risk of cardiovascular health problems.
Less than 0.9 - low risk of cardiovascular health problems
0.9 to 0.99 - moderate risk of cardiovascular health problems
1 or over - high risk of cardiovascular problems
Less than 0.8 - low risk of cardiovascular health problems
0.8 to 0.89 - moderate risk of cardiovascular health problems
0.9 or over - high risk of cardiovascular problems
The WHR of a person is a much better indicator of whether their body weight is ideal and what their risks of developing serious health conditions are, compared to BMI. Various studies have shown that people with apple-shaped bodies - who have larger WHRs - have higher health risks compared to people with pear-shaped bodies - who have lower WHRs. An apple-shaped person will have more fat accumulating on the waist, while a pear-shaped person has the fat accumulating on the hips.
A woman with a WHR of less than 0.8 is generally healthier and more fertile than females with higher WHRs. They are less likely to develop diabetes, most cancers, or cardiovascular disorders. Similarly, men with a WHR no more than 9 are generally healthier and more fertile than men with higher WHRs, and less likely to develop serious conditions or diseases.
Studies indicate that if WHR were to replace BMI as a predictor of heart attack worldwide, figures would include many more people.
What is the problem with WHR?
WHR does not accurately measure a person's total body fat percentage, or their muscle-to-fat ratio. However, it is a better predictor of ideal weight and health risks than BMI.
measuring your hips
Dr Margaret Ashwell, who used to be science director of the British Nutrition Foundation, and team have found that waist-to-height ratio is better at predicting future heart disease and diabetes risk than BMI.
Dr. Ashwell presented their findings at the 19th Congress on Obesity in Lyon, France, on 12th May, 2012.
Dr. Ashwell said, in an interview with The Daily Telegraph, a leading UK newspaper:
"Keeping your waist circumference to less than half your height can help increase life expectancy for every person in the world."
A man 6ft (72 inches, 183 cm) tall, should keep his waist measurement below 36 inches (91 cm)
A woman 5ft 4 inches, i.e. 64 inches (163 cm) tall, should keep her waist measurement below 32 inches (81 cm)
Dr. Ashwell says waist-to-height ratio (WHtR) should be used as a screening tool.
The team found that after analyzing several studies involving approximately 300,000 people, they concluded that WHtR is better at predicting heart attacks, stroked, diabetes, and hypertension risk compared to BMI.
Ashwell explains that BMI does not take into account fat distribution around the body. The accumulation of abdominal fat (visceral fat) may be harmful for the heart, kidneys and liver, while fat build-up around the hips and bottom is less hazardous to health.
The researchers added that WHtR is much simpler for people to work out:
“Keep your waist circumference to less than half your height"
How do you measure your waist? - measure it mid-way between the lower rip and the iliac crest (the top of the pelvic bone at the hip), says WHO (World Health Organization). ("Waist To Height Ratio Better Than BMI". Catharine Paddock PhD. Medical News Today. 13 May 2012)
measuring your waist
What is Body Fat Percentage?
Your body fat percentage is the weight of your fat divided by your total weight. The result indicates your essential fat as well as storage fat.
Essential fat - this is the amount of fat we need to survive. Women require a higher percentage than men. Essential fat is 2%-5% in men, and 10%-13% in women.
Storage fat - this consists of fat accumulation in adipose tissue, some of which protects our internal organs in the chest and abdomen.
Total body fat percentage - this is essential fat plus storage fat.
The American Council on Exercise recommends the following percentages:
Non-athletes classed as fit
Men 38% or more
Women 42% or more
Many experts say that calculating people's body fat percentage is the best way to gauge their fitness level because it is the only measurement that includes the body's true composition. Any male whose body fat percentage is over 25% or female over 31% is either overweight or possibly obese.
Body fat percentage would not make the couch potato seem fitter than the 100 meter Olympic champion - as was the case with BMI.
There are various ways of calculating a person's body fat percentage. None of them can give a 100% accurate figure, but the estimates are accepted as fairly close. Examples include near-infrared interactance, dual energy X-ray absorptiometry, and bioelectrical impedance analysis.
Many gyms and doctor's practices have devices that can tell you what your body fat percentage is.
Weight - Height Charts
We have included two charts giving you average weight measurements for men and women based upon height and frame size.
The assumed age is 25-59 years and weight measurements are in pounds (lb).
Weight - height chart
Chart from Ygraph
Weight and height chart for women and men with weight in kilos and height in feet and inches and meters.
Weight - height chart 2
Chart from Ygraph
Conclusion about your ideal weight
This article has briefly explained four ways to help you find out whether your weight is ideal, and what your target should be if it is not. You can work out your BMI (body mass index), WHR (waist-hip ratio), WHtR (waist-height ratio) or Body Fat Percentage.
BMI, WHR and WHtR can be done easily in your home. WHR and WHtR are more accurate than BMI. However, BMI is a useful indicator if you are an "average" person - not an Olympic athlete or a dedicated weight trainer.
If you embark on a weight loss regime that includes exercise and diet, bear in mind that the exercise will probably increase your muscle mass, which may increase your weight, even though your waist may shrink. Muscle weighs more than fat.
It might be better to aim for target waist, hips and chest measurements. A Waist-hip ratio goal is also possible. If you feel really dedicated, check your Body Fat Percentage; if you are not happy with the reading, discuss a realistic target with a nutritionist, sports scientist, or personal trainer and go for it!