What is Ideal Weight?
Ideal weight, sometimes called ideal body weight (IBW), is the weight range at which a person is considered to be at the lowest risk for weight-related health problems. It is not a single magic number but rather a range of weights that corresponds to a healthy body composition for your height, age, and gender. Maintaining a weight within this range is associated with lower rates of heart disease, type 2 diabetes, joint problems, and certain cancers.
It is important to understand that ideal weight is a general guideline, not an absolute standard. Two people of the same height can have very different ideal weights depending on their muscle mass, bone structure, and overall fitness level. A professional athlete may weigh significantly more than the calculated ideal weight due to muscle mass, yet still be in excellent health.
Despite these limitations, ideal weight formulas provide a useful starting point for setting realistic health goals. They are widely used in clinical settings for drug dosing, nutritional planning, and assessing whether a patient falls within a healthy weight range. Understanding the different formulas and their results gives you a well-rounded perspective on what a healthy weight means for your body.
Popular Formulas for Ideal Weight
Several formulas have been developed over the decades to estimate ideal body weight. Each was created for a slightly different purpose and population, which is why they produce different results. Here are the four most widely used formulas:
Devine Formula (1974)
Originally developed for calculating drug dosages, the Devine formula is one of the most commonly referenced ideal weight equations:
- Men: IBW (kg) = 50 + 2.3 x (height in inches - 60)
- Women: IBW (kg) = 45.5 + 2.3 x (height in inches - 60)
Robinson Formula (1983)
The Robinson formula was developed as a modification of the Devine formula, adjusting the coefficients based on updated clinical data:
- Men: IBW (kg) = 52 + 1.9 x (height in inches - 60)
- Women: IBW (kg) = 49 + 1.7 x (height in inches - 60)
Miller Formula (1983)
The Miller formula also refined the Devine equation, producing estimates that tend to be slightly higher for taller individuals:
- Men: IBW (kg) = 56.2 + 1.41 x (height in inches - 60)
- Women: IBW (kg) = 53.1 + 1.36 x (height in inches - 60)
Hamwi Formula (1964)
One of the earliest ideal weight formulas, the Hamwi method is still used by some nutritionists and healthcare providers:
- Men: IBW (kg) = 48 + 2.7 x (height in inches - 60)
- Women: IBW (kg) = 45.5 + 2.2 x (height in inches - 60)
Each formula gives a single-point estimate, so it is useful to compare results from multiple formulas to get a reasonable range rather than fixating on one number. You can calculate all four results at once using our Ideal Weight Calculator.
Ideal Weight by Height Table
The following table shows approximate ideal weight ranges for men and women based on the average of the four formulas above. These values assume a medium body frame:
- 150 cm (4'11"): Men: 47-52 kg | Women: 43-49 kg
- 155 cm (5'1"): Men: 51-56 kg | Women: 47-52 kg
- 160 cm (5'3"): Men: 55-61 kg | Women: 50-56 kg
- 165 cm (5'5"): Men: 59-66 kg | Women: 53-60 kg
- 170 cm (5'7"): Men: 63-71 kg | Women: 57-63 kg
- 175 cm (5'9"): Men: 67-76 kg | Women: 60-67 kg
- 180 cm (5'11"): Men: 72-81 kg | Women: 63-71 kg
- 185 cm (6'1"): Men: 76-86 kg | Women: 67-75 kg
- 190 cm (6'3"): Men: 80-91 kg | Women: 70-79 kg
These ranges are approximate and should be used as general guidelines. Your actual ideal weight may fall outside these ranges depending on your body composition, muscle mass, and individual health factors.
BMI-Based Ideal Weight Range
Another approach to determining a healthy weight is to use the Body Mass Index (BMI). The World Health Organization classifies a BMI between 18.5 and 24.9 as the normal, healthy range. You can use this to calculate your ideal weight range based on your height:
Ideal Weight Range = BMI range x (height in meters)^2
For example, a person who is 170 cm (1.70 m) tall would have an ideal weight range of:
- Lower end: 18.5 x (1.70)^2 = 18.5 x 2.89 = 53.5 kg
- Upper end: 24.9 x (1.70)^2 = 24.9 x 2.89 = 72.0 kg
This gives a healthy weight range of approximately 53.5 to 72.0 kg for someone 170 cm tall. The BMI-based range is broader than the formula-based estimates, which makes it more flexible for accommodating different body types. You can check your current BMI and see where you fall using our BMI Calculator.
Factors That Affect Ideal Weight
No single formula can account for all the variables that influence what a truly healthy weight looks like for a specific individual. Here are the key factors that affect your ideal weight:
- Age: Metabolic rate decreases with age, and body composition changes naturally over time. Older adults tend to have less muscle and more fat compared to younger adults at the same weight. Ideal weight ranges may need slight upward adjustment for older individuals.
- Muscle mass: Muscle is denser and heavier than fat. Athletes, bodybuilders, and physically active individuals often weigh more than their calculated ideal weight while maintaining an excellent body fat percentage. For these individuals, body fat measurements are more meaningful than weight alone.
- Body frame size: People with larger bone structures naturally weigh more. A person with a large frame may have an ideal weight that is 10% higher than the standard estimates, while someone with a small frame may fall 10% below.
- Genetics: Your genetic makeup influences your body's natural weight distribution, metabolic rate, and tendency to store fat in certain areas. Some people are genetically predisposed to carry more weight and may be perfectly healthy at a weight that exceeds the formula-based ideal.
- Gender: Men generally have more muscle mass and denser bones than women, which is why the ideal weight formulas produce higher values for men at the same height.
Why One Formula Isn't Enough
If you calculate your ideal weight using all four formulas, you will likely get four different numbers. This is not a flaw in the formulas but rather a reflection of the fact that ideal weight is a range, not a single number. Each formula was developed using different study populations and for different clinical purposes.
The best approach is to consider the results from multiple formulas as establishing a reasonable range. If three out of four formulas suggest an ideal weight between 65 and 72 kg for your height, then any weight within that range is likely appropriate. Combining these estimates with a BMI check and, if possible, a body fat percentage measurement gives you the most complete picture of your health status.
It is also worth noting that health markers such as blood pressure, blood sugar levels, cholesterol, and cardiovascular fitness are equally important indicators of overall health. A person whose weight is slightly above the calculated ideal but who maintains excellent cardiovascular fitness and normal blood markers may be healthier than someone at the ideal weight who is sedentary.
Tips for Achieving a Healthy Weight
If your current weight falls outside the healthy range, here are evidence-based strategies for moving toward your ideal weight:
- Set realistic goals: Aim to lose or gain 0.5 to 1 kg per week. Rapid weight changes are difficult to maintain and can be harmful to your health.
- Focus on nutrition quality: Prioritize whole foods including vegetables, fruits, lean proteins, whole grains, and healthy fats. Reducing processed foods and added sugars is often more effective than strict calorie counting.
- Incorporate regular exercise: Combine cardiovascular exercise with strength training. Cardio burns calories and improves heart health, while strength training builds muscle and raises your resting metabolic rate.
- Monitor your progress: Weigh yourself at the same time each week under consistent conditions. Track trends over weeks and months rather than daily fluctuations.
- Get adequate sleep: Poor sleep disrupts hunger hormones (ghrelin and leptin), increasing appetite and cravings. Aim for 7 to 9 hours of quality sleep each night.
- Stay hydrated: Drinking sufficient water supports metabolism and can help reduce overeating. Sometimes thirst is mistaken for hunger.
- Consult a professional: If you are significantly above or below the ideal weight range, consider working with a dietitian or healthcare provider who can create a personalized plan based on your medical history and goals.
Your ideal weight is a personal target that depends on many factors unique to you. Use our Ideal Weight Calculator and BMI Calculator as starting points, then work toward a weight that allows you to feel energetic, healthy, and confident in your daily life.