Ideal Body Weight Calculator
The short answer: Ideal body weight formulas estimate a healthy weight range from your height and sex. This calculator shows results from four classic formulas: Devine, Robinson, Miller and Hamwi, each in kilograms and pounds. They were developed for clinical drug dosing and ignore frame size and muscle, so treat them as reference points, not personal targets.
What Is Ideal Body Weight?
Ideal body weight (IBW) estimates a healthy weight for your height, originally created so doctors could dose medications safely. The first widely used formula came from Dr. B. J. Devine in 1974, built for drugs dosed by lean body mass. Later researchers proposed their own versions, each fitted to different study populations.
Understand what IBW is not: not a diagnosis, not a science-backed fitness goal, and not sensitive to whether your weight comes from muscle or fat. A lean 200-pound athlete and a sedentary 200-pound adult get the same IBW at the same height. Use it as one data point alongside broader measures like a BMI calculator and a body fat percentage calculator, which capture different aspects of body composition.
The Four Formulas
All four formulas start from a base weight at 5 feet tall and add a fixed amount per inch above 5 feet. Here are the equations, with results in kilograms:
| Formula | Male | Female |
|---|---|---|
| Devine (1974) | 50 + 2.3 x in over 5 ft | 45.5 + 2.3 x in over 5 ft |
| Robinson (1983) | 52 + 1.9 x in over 5 ft | 49 + 1.7 x in over 5 ft |
| Miller (1983) | 56.2 + 1.41 x in over 5 ft | 53.1 + 1.36 x in over 5 ft |
| Hamwi (1964) | 48 + 2.7 x in over 5 ft | 45.5 + 2.2 x in over 5 ft |
Hamwi gives the highest values and Miller the lowest for most heights, with Devine and Robinson in the middle. The spread, often 3 to 5 kg, shows how approximate any single “ideal” number is. This calculator shows all four so you see the range, not a false-precision single answer.
How to Use This Calculator
- Enter your height. Type it in centimeters, or switch to feet and inches. Measure without shoes, standing straight against a wall.
- Select your sex. The formulas use different base weights for males and females.
- Read the four results. Each formula’s ideal weight appears in kilograms and pounds. The spread across the four is your realistic reference range.
- Interpret with context. Compare the range against your frame, muscle mass and health markers rather than chasing one number.
If you want to move toward a healthier weight, a calorie deficit calculator sets a safe pace, and a macro calculator keeps your nutrition balanced along the way.
Example Results
Verified results for three profiles:
| Formula | Male, 5 ft 10 in | Female, 5 ft 4 in | Male, 6 ft 0 in |
|---|---|---|---|
| Devine | 73.0 kg (160.9 lb) | 54.7 kg (120.6 lb) | 77.6 kg (171.1 lb) |
| Robinson | 71.0 kg (156.5 lb) | 55.8 kg (123.0 lb) | 74.8 kg (164.9 lb) |
| Miller | 70.3 kg (155.0 lb) | 58.5 kg (129.0 lb) | 73.1 kg (161.2 lb) |
| Hamwi | 75.0 kg (165.3 lb) | 54.3 kg (119.7 lb) | 80.4 kg (177.3 lb) |
Check the first column: 5 ft 10 in is 70 inches, so 10 inches over 5 ft. Devine male: 50 + 2.3 x 10 = 73.0 kg, and 73.0 x 2.20462 = 160.9 lb. Hamwi male: 48 + 2.7 x 10 = 75.0 kg. For the female 5 ft 4 in column (4 inches over): Miller gives 53.1 + 1.36 x 4 = 58.5 kg, notably higher than the other three, which shows why comparing formulas matters.
Limitations to Know
The formulas were calibrated on mid-20th-century clinical populations for drug dosing, not for setting personal fitness targets. They ignore frame size: a broad-shouldered person and a slight person of the same height get identical numbers. They ignore muscle mass, so lifters and athletes routinely land above their IBW while being perfectly healthy. They ignore age, even though healthy weight tends to shift slightly with age, and they behave oddly below 5 feet, where the “inches over 5 feet” term goes negative.
None of this makes them useless. As a quick clinical reference or a starting point for a conversation with your doctor, they are fine. As the sole judge of whether your weight is healthy, they are not. Combine them with body fat estimates, waist measurements, blood work and how you actually feel and perform.
Frequently Asked Questions
What is the most accurate ideal weight formula?
No single formula wins. Devine remains the clinical standard for drug dosing, while Robinson, Miller and Hamwi fit different study populations. Because they disagree by several kilograms, the honest answer is the range across all four, which is what this calculator shows.
What is the difference between IBW and BMI?
Ideal body weight gives a target weight in kg or lb from your height and sex. BMI gives an index number (weight divided by height squared) that classifies you as underweight, normal, overweight or obese. They answer different questions: IBW suggests a weight, BMI categorizes the weight you have.
Why do the four formulas disagree?
Each was derived from a different population and a different era, with different assumptions about frame and body composition. The disagreement is a feature, not a bug: it reminds you that “ideal weight” is a range, not a precise number anyone can calculate for you.
Do these formulas work for athletes?
Not well. Muscle is denser than fat, so muscular athletes often exceed their IBW by a wide margin while staying lean. Athletes should rely on body fat percentage, performance metrics and professional guidance instead.
What if I am shorter than 5 feet?
The formulas still compute, but the inches-over-5-feet term becomes negative and the results are extrapolations the original researchers never validated. Treat results below 5 feet as rough guides only and discuss targets with a clinician.
Should I aim for my ideal body weight?
Use it as a reference, not a mandate. Sustainable health comes from habits: balanced nutrition, regular movement, sleep and strength. If your weight is well above the IBW range, set the pace with a calorie deficit plan rather than chasing one formula’s number.
Learn More
These calculators round out your weight and health planning: