Question 1

What is ideal body weight?

Accepted Answer

Ideal body weight (IBW) is a clinical estimate of the weight at which a person of a given height is considered healthiest based on population studies. It was originally developed for medication dosing in healthcare, not as a fitness target. IBW formulas assume a medium body frame and do not account for individual differences in muscle mass, bone density, or body composition. Use IBW as a reference point rather than an absolute goal.

Question 2

Why does this calculator show four different formulas?

Accepted Answer

No single formula for ideal weight is universally accepted. The Robinson, Devine, Miller, and Hamwi formulas were each developed from different population studies over several decades (1964-1983) and produce slightly different results. By showing all four and their average, you get a realistic weight range rather than a single misleading number. The range typically spans 3-6 kg, reflecting the natural variation in what constitutes a healthy weight for a given height.

Question 3

Is ideal weight the same as healthy weight?

Accepted Answer

Not exactly. Ideal weight formulas are simplified estimates based on height and gender only. A "healthy weight" considers additional factors like body fat percentage, waist circumference, metabolic health markers (blood pressure, blood sugar, cholesterol), fitness level, and age. Someone outside their calculated ideal weight range can be perfectly healthy if their body composition, fitness, and metabolic markers are good. BMI and body fat percentage provide complementary perspectives.

Question 4

How does gender affect ideal weight?

Accepted Answer

All four formulas produce lower ideal weights for women than men at the same height, reflecting the biological difference in body composition. Men naturally carry more muscle mass and have larger bone structures on average. The Devine formula shows the largest gender gap (4.5 kg base difference), while the Miller formula shows the smallest (3.1 kg). These differences align with observed population averages but may not apply to individuals with atypical body composition.

Question 5

What if I am shorter than 152 cm (5 feet)?

Accepted Answer

The original formulas were designed for heights above 60 inches (152.4 cm). For shorter individuals, the formulas use their base values (which is the ideal weight at exactly 5 feet). The results are less reliable for very short adults. If you are under 152 cm, BMI-based weight ranges (maintaining a BMI of 18.5-24.9) may give you a more useful estimate of healthy weight than these height-based formulas.

Question 6

Should I aim for the Devine, Robinson, Miller, or Hamwi result?

Accepted Answer

Use the average of all four as your target midpoint, and consider the full range as your healthy zone. The Devine formula tends to produce higher values and was originally created for drug dosing; the Miller formula tends to produce the highest values for men. If you are naturally lean and small-framed, the lower end (Robinson or Devine for women) may be more appropriate. If you have a larger build or more muscle mass, the upper end (Hamwi) may be more realistic.

Question 7

How do I reach my ideal weight safely?

Accepted Answer

A safe rate of weight change is 0.5-1 kg per week. To lose weight, create a 500-calorie daily deficit through diet and exercise. To gain weight (lean mass), eat a 300-500 calorie surplus with adequate protein (1.6-2.2g/kg) and resistance training. Focus on sustainable habits: eat whole foods, strength train 3-4x per week, sleep 7-9 hours, and manage stress. Crash diets and extreme calorie restriction lead to muscle loss, metabolic slowdown, and almost always rebound weight gain.

Ideal Weight Calculator — Find Your Ideal Body Weight