Ideal Weight Calculator

Understanding Ideal Body Weight

Ideal body weight (IBW) formulas were developed in clinical settings to provide quick, practical weight estimates for specific medical purposes — primarily medication dosing, nutritional assessment, and patient monitoring. They are not aesthetic benchmarks or personal weight loss goals. Understanding their context helps interpret the results accurately.

The most widely used clinically is the Devine formula (1974), developed originally for aminoglycoside antibiotic dosing. It remains the most referenced IBW formula in pharmacology textbooks worldwide. However, for general health purposes, the WHO healthy BMI range (18.5–24.9) provides a more nuanced and evidence-based weight range that accounts for individual variation.

The Difference Between Ideal Weight and Healthy Weight

Ideal weight formulas produce a single-point estimate — one number. The BMI-based healthy weight range, on the other hand, produces a range (for example, 57–76 kg for a 175 cm person). This range is more clinically appropriate because it acknowledges that many different body compositions can be equally healthy.

A very muscular 175 cm man who weighs 82 kg is almost certainly healthier than his BMI suggests, while the Devine IBW of ~68 kg would seem unrealistically low. This is why using the average of multiple formulas — as this calculator does — alongside the BMI range, provides the most balanced perspective.

How to Reach and Maintain a Healthy Weight

If your current weight is above your healthy range, a slow, sustained approach is most effective. Use our TDEE Calculator to find your maintenance calories, then create a moderate deficit of 300–500 kcal/day. At this rate, you can expect to lose 0.3–0.5 kg per week — slow enough to preserve lean muscle mass.

If your weight is below the healthy range, focus on calorie-dense, nutrient-rich foods: nuts, avocados, whole grains, lean proteins, and dairy. Use our Calorie Calculator to set a target 300–500 kcal above your TDEE, and incorporate resistance training to ensure weight gained is primarily lean mass.