A healthy weight can depend on many factors, including your age, sex, muscle mass, bone mass, and lifestyle. Some measures, like body mass index (BMI), do not take all of these measures into account.

There’s no perfect formula to find your ideal body weight because it’s influenced by many factors, such as:

• height
• genetics
• sex assigned at birth
• sleep
• activity level
• body composition
• underlying health conditions
• whether you take any medications

When calculating ideal weight for adults, age isn’t typically a factor because people of the same age vary widely in height, shape, and size. What’s best for you may not be best for someone else your age.

However, age is a factor when calculating the ideal weight for children and teenagers ages 2 to 19 years old because they’re still growing.

## Height and body mass index (BMI)

Body mass index (BMI) is an approximate calculation of your body mass, which is used to predict your amount of body fat based on your height in inches and weight in pounds (lbs).

BMI numbers range from low to high and fall into several categories:

CategoryBMI range
Underweightless than 18.5
Moderate weight18.5 to 25
Overweight25 to 30
Obese• class 1: 30 to 35
• class 2: 35 to 40
• class 3: 40 or greater

To calculate your BMI, divide your weight in pounds by your height in inches squared. Multiply that result by 703.

You can also enter this information into the BMI calculator below.

Here’s a look at a BMI chart by height according to the National Heart, Lung, and Blood Institute (NHLBI):

BMI range18.5 to 24.925 to 29.930 to 34.935 to 39.940 or greater
Height (inches)
5891 to 115 lbs119 to 138 lbs143 to 162 lbs167 to 186 lbs≥ 191 lbs
5994 to 119 lbs124 to 143 lbs148 to 168 lbs173 to 193 lbs≥ 198 lbs
6097 to 123 lbs128 to 148 lbs153 to 174 lbs179 to 199 lbs≥ 204 lbs
61100 to 127 lbs132 to 153 lbs158 to 180 lbs185 to 206 lbs≥ 211 lbs
62104 to 131 lbs136 to 158 lbs164 to 186 lbs191 to 213 lbs≥ 218 lbs
63107 to 135 lbs141 to 163 lbs169 to 191 lbs197 to 220 lbs≥ 225 lbs
64110 to 140 lbs145 to 169 lbs174 to 197 lbs204 to 227 lbs≥ 232 lbs
65114 to 144 lbs150 to 174 lbs180 to 204 lbs210 to 234 lbs≥ 240 lbs
66118 to 148 lbs155 to 179 lbs186 to 210 lbs216 to 241 lbs≥ 247 lbs
67121 to 153 lbs159 to 185 lbs191 to 217 lbs223 to 249 lbs≥ 255 lbs
68125 to 158 lbs164 to 190 lbs197 to 223 lbs230 to 256 lbs≥ 262 lbs
69128 to 162 lbs169 to 196 lbs203 to 230 lbs236 to 263 lbs≥ 270 lbs
70132 to 167 lbs174 to 202 lbs209 to 236 lbs243 to 271 lbs≥ 278 lbs
71136 to 172 lbs179 to 208 lbs215 to 243 lbs250 to 279 lbs≥ 286 lbs
72140 to 177 lbs184 to 213 lbs221 to 250 lbs258 to 287 lbs≥ 294 lbs
73144 to 182 lbs189 to 219 lbs227 to 257 lbs265 to 195 lbs≥ 302 lbs
74148 to 186 lbs194 to 225 lbs233 to 264 lbs272 to 303 lbs≥ 311 lbs
75152 to 192 lbs200 to 232 lbs240 to 272 lbs279 to 311 lbs≥ 319 lbs
76156 to 197 lbs205 to 238 lbs246 to 279 lbs287 to 320 lbs≥ 328 lbs

## How is BMI calculated for children?

BMI for people ages 2 to 19 years old calculates an age-specific percentile and also factors in sex assigned at birth.

You can use the Centers for Disease Control and Prevention’s BMI calculator to calculate a child’s BMI.

This number can then be plotted on a chart for boys and girls to compare weight to other people the same age.

For instance, a 5-year-old boy at the 25th percentile weighs less than 75% of boys their age and more than 25% of boys their age.

Like BMI for adults, the NHLBI classifies BMI for children into several categories:

CategoryBMI percentile
Underweightbelow 5th percentile
Healthy weight5th to 85th percentile
Overweight85th to 95th percentile
Obesityabove 95th percentile

### BMI isn’t the only measurement

It’s helpful that BMI numbers are standardized and offer ranges of moderate body weights by height. However, BMI is only one measure and doesn’t tell the whole story.

BMI calculations don’t consider several physical, lifestyle, and medical factors that could influence your body weight.

For instance, it doesn’t consider differences in bone, muscle, and fat mass between age groups and sex assigned at birth.

This means an active person with a lot of muscle could be misclassified as having overweight or obese. Similarly, a person with lower muscle or bone mass may be misclassified as underweight if they have high body fat levels. In other words, BMI could underestimate how much fat you have.

BMI cutoffs were also designed by a mathematician based on a white male European population and may be inaccurate for other races and ethnicities.

BMI may be helpful for assessing health risks at the population level, but it’s important for individuals to perform several tests to determine the ideal weight for their age and height.

## Waist-to-height ratio

The waist-to-height ratio is another tool to help determine the amount of fat around your waist and whether you have a moderate weight for your height.

Measuring your waist circumference aims to assess visceral fat, a type of fat stored in the abdominal region around your organs. Visceral fat is associated with an increased risk of cardiometabolic risk.

Subcutaneous fat, on the other hand, is a type of fat stored under your skin and is responsible for storing energy.

Where you store fat is important for assessing health risks, and BMI can’t tell you this.

According to the British Heart Foundation, having more fat around your waist is associated with health conditions, such as:

Here’s how to measure your waist-to-height ratio at home:

1. Stand up tall.
2. Wrap a tape measure around your body between your ribs and hips.
3. Make sure the tape measure is snug against your skin, but not digging in.
4. Make note of the measurement, either in centimeters or inches.
5. Measure your height in the same metric unit.

A 6-foot-tall person (72 inches) with a waist measurement of 36 inches would have a ratio of 0.5.

Research suggests that if your waist measurement is more than half of your height (over 0.5), you may have an increased risk of obesity-related illnesses, such as cardiovascular problems and early death.

A small 2017 study found that waist-to-height ratio might be a better indicator of obesity than BMI. That said, more research is needed to compare larger numbers of people including more diversity in age and ethnicity.

## Waist-to-hip ratio

Calculating your waist-to-hip (WHR) ratio is a third tool to help determine whether you have a moderate weight.

Similar to the waist-to-height ratio, a higher WHR is associated with health conditions like metabolic syndrome.

A healthy WHR ratio for males is below 0.95, and for females, 0.85.

Some experts believe the WHR ratio might be a better way than BMI for assessing health risks.

That said, the WHR ratio is not a good tool for everyone, including children, pregnant people, and those who are shorter than average.

## Body fat percentage

Calculating your body fat percentage may provide the most accurate measurement of how much fat you have.

Methods to assess body fat percentage may include:

Some at-home tools are available to do this. However, these aren’t consistently accurate.

It’s best to work with a healthcare professional.

### What is the correct weight according to age?

There’s no correct weight according to age because people of a single age could vary widely in height, shape, and size. A healthcare professional could help determine a moderate weight for you.

### How do you calculate weight for age?

Age isn’t typically a factor when calculating weight for adults. However, some ways to determine whether you have a moderate weight for your height include waist-to-height ratio, waist-to-height ratio, BMI, and body fat percentage.

## Takeaway

There’s no perfect way to determine your ideal weight, as it depends on many factors. These factors include your body fat percentage and distribution, as well as your age, height, and sex assigned at birth.

Speak with a healthcare professional if you’re unsure about how much you should weigh. They could help you determine your moderate weight and develop a plan to achieve your weight goals.