Knowing how much you should weigh for your height is a common question. There is no single body weight that is ideal for everyone, because body composition, age, muscle mass, and other factors can affect what a healthy weight looks like. However, ideal body weight (IBW) formulas can provide a useful reference point based mainly on height and sex.
One commonly used method is the Devine formula, which estimates ideal body weight from height. It is simple to calculate and is widely referenced in medical and clinical contexts. Our Ideal Body Weight Calculator uses the Devine formula to provide an estimate in kilograms and pounds.
Not medical advice: An ideal body weight estimate is a height-based reference number. It is not a diagnosis, a required target, or a substitute for advice from a qualified healthcare professional.
What Is Ideal Body Weight?
Ideal body weight is an estimated weight based primarily on a person's height and sex. It should be understood as a reference value rather than an exact target that every person should reach.
For example, two people with the same height can have different healthy weights because they may have different amounts of muscle, bone mass, and body fat. An ideal body weight calculation does not measure these differences.
This is why an IBW estimate is most useful when considered alongside other information rather than used by itself.
How Does the Devine Formula Work?
The Devine formula starts with a 5-foot baseline (50 kg for men; 45.5 kg is the Devine 5-foot female baseline, not a calculator minimum) and then applies 2.3 kg for each inch of height above or below 5 feet.
Men: Ideal Body Weight = 50 kg + 2.3 kg × (inches over 5 feet)
Women: Ideal Body Weight = 45.5 kg + 2.3 kg × (inches over 5 feet)
Example: a man who is 5 feet 10 inches tall is 10 inches above 5 feet:
50 + (2.3 × 10) = 73 kg
The Devine formula therefore estimates approximately 73 kg for this example. That figure is still an estimate. It is not a precise measurement of one person's healthy weight, because the formula only uses height and sex.
The Devine estimate adds 2.3 kg for each inch over 5 feet, from a different starting weight for men and women.
What About Height in Centimeters?
The formula is written in inches, so centimeter heights need a conversion first:
Height in inches = height in centimeters ÷ 2.54
Example: 180 cm is approximately 70.87 inches (180 ÷ 2.54). That is about 10.87 inches over 5 feet (60 inches), which is the input the Devine formula uses.
The ToolsTask Ideal Body Weight Calculator performs this conversion automatically when you enter height in centimeters, then shows the estimate in kilograms and pounds.
Ideal Body Weight Examples by Height
The table below lists sample Devine estimates. Small differences can appear because of rounding when centimeters are converted to inches.
| Height | Male IBW | Female IBW |
|---|---|---|
| 150 cm | 47.8 kg | 43.3 kg |
| 160 cm | 56.9 kg | 52.4 kg |
| 170 cm | 65.9 kg | 61.4 kg |
| 180 cm | 75.0 kg | 70.5 kg |
| 190 cm | 84.0 kg | 79.5 kg |
Is Ideal Body Weight the Same as a Healthy Weight?
IBW and healthy weight are not necessarily the same. A healthy weight for one person is usually a range, not a single kilogram value, and it depends on more than height and sex.
IBW does not directly measure:
- muscle mass
- body fat
- bone structure
- age
- physical activity
For that reason, IBW should be treated as a reference rather than a universal definition of healthy weight.
Ideal Body Weight vs. BMI
IBW estimates a reference weight mainly from height and sex. It does not use your current scale weight.
BMI uses actual weight and height:
BMI = weight in kilograms ÷ height in meters²
The two measurements serve different purposes. IBW answers “what weight does this height-based formula estimate?” BMI answers “how does this person's current weight compare with height?” Neither one is a complete health assessment. If you want to run BMI from your current weight, use the BMI Calculator.
What If My Result Is Different From My Current Weight?
It is normal for current weight to differ from an IBW estimate. A difference does not automatically mean someone needs to gain or lose weight.
The formula does not know the person's muscle mass, body composition, lifestyle, or individual circumstances. Athletes, people with larger frames, and people with more muscle often weigh more than a height-only estimate while remaining healthy. The reverse can also be true. Treat a gap as information, not as an instruction.
Limitations of Ideal Body Weight Formulas
- Devine is a height-based estimate. It was originally used in clinical dosing contexts, not as a complete picture of health.
- It does not measure body composition.
- It does not account for every individual characteristic, including age, frame size, and training history.
- It should not be treated as a medical diagnosis.
- It should not automatically be treated as a guaranteed healthy-weight range.
How to Use an Ideal Body Weight Calculator
- Select your sex.
- Enter your height in centimeters.
- Select Calculate.
- Review the estimated ideal body weight in kilograms and pounds.
- Use the result as a general reference rather than an exact personal target.
Try the on-site calculator
The ToolsTask Ideal Body Weight Calculator applies the Devine formula, converts centimeters to inches for you, and shows the estimate in kilograms and pounds.
Open Ideal Body Weight Calculator →Frequently Asked Questions
What is the Devine ideal body weight formula?
It is a height-based estimate: 50 kg plus 2.3 kg for each inch over 5 feet for men, and 45.5 kg plus 2.3 kg for each inch over 5 feet for women. The ToolsTask calculator uses this method.
Can I use ideal body weight for weight-loss goals?
You can use it as one reference number, but it should not be treated as a required goal. Weight-change decisions depend on health, body composition, and professional advice. An IBW result is not a diet plan.
Why can two people with the same height have different healthy weights?
Muscle, fat, bone, and frame size differ from person to person. A formula that only uses height and sex cannot capture those differences, so two people of the same height can reasonably sit at different weights.
Is ideal body weight more accurate than BMI?
Neither is inherently “more accurate” for health. They measure different things. IBW estimates a reference weight from height and sex. BMI compares current weight with height. Accuracy for an individual depends on context, not on picking one number as the winner.
Does the Devine formula work for everyone?
No. It is a simplified adult estimate. It does not fit children, and it is a weaker fit for people whose body composition differs a lot from what a height-only model assumes. It also becomes more approximate at heights well below 5 feet.
Can I calculate ideal body weight in pounds?
Yes. Convert the kilogram estimate using 1 kg = 2.2046226218 lb. The ToolsTask calculator already displays both kilograms and pounds after you calculate.
Final Takeaway
Ideal body weight is best understood as a reference estimate rather than a precise definition of healthy weight. The Devine formula provides a simple estimate from height and sex, but it does not account for every factor that affects appropriate body weight.
If you want a working example of the same method, use the Ideal Body Weight Calculator and read the result as a reference, not as a verdict.