Ideal Weight Calculator

How to Use This Ideal Weight Calculator

1. Select height unit: Choose centimetres (cm) or feet & inches, whichever you are comfortable with. The calculator converts between units automatically.
2. Enter your height: In cm mode, type your height or use the slider. In feet & inches mode, enter feet and inches in the two separate fields (e.g., 5 feet 7 inches).
3. Select gender: Choose Male or Female. The formulas use gender to adjust for typical differences in muscle mass and body composition between men and women.
4. Click Calculate Ideal Weight: The results show five reference points — the BMI-based healthy range, four individual formula results (Devine, Robinson, Miller, Hamwi), and the consensus average of the four formulas.

Use the BMI range as your primary reference — it gives a realistic band rather than a single fixed number. The individual formulas are useful for comparison and are commonly used in clinical and pharmaceutical settings.

The Five Ideal Weight Formulas Explained

1. BMI-Based Healthy Weight Range

The World Health Organisation defines a healthy BMI as 18.5–24.9. This gives a range rather than a single ideal weight, which is more realistic since a healthy weight is not one specific number. For a 170 cm person, the range is approximately 53.4–72 kg.

2. Devine Formula (1974)

Developed by B.J. Devine for calculating drug dosages in clinical settings. It remains the most widely cited single-point ideal weight formula in medical literature, though it was never designed as a general health guideline.

3. Robinson Formula (1983)

Published by J.D. Robinson as a revision of the Devine formula with a slightly higher baseline and lower per-inch increment. It tends to give more conservative (lower) ideal weights than Devine for taller individuals.

4. Miller Formula (1983)

Developed by D.R. Miller in the same year as Robinson. It uses a higher baseline than Devine but the smallest per-inch increment among the four formulas, resulting in relatively similar results across a wide range of heights.

5. Hamwi Formula (1964)

The oldest of the four single-point formulas, developed by G.J. Hamwi. It uses the largest per-inch increment for men (2.7 kg), giving the highest ideal weight estimates for taller males among all four formulas.

Consensus Average

This calculator also shows the simple arithmetic mean of all four formula results as a "consensus" figure — a reasonable middle-ground reference point when the formulas diverge.

Example Calculations

BMI Range vs Single-Point Formulas

The key difference between the BMI approach and the four formulas is range vs single number:

• BMI-based range acknowledges that there is no one "perfect" weight — a healthy weight is a band. For most people, this 18.5–24.9 range is the most practical and widely accepted reference. A 175 cm person can be healthy anywhere between 57 and 76 kg.
• Single-point formulas (Devine, Robinson, Miller, Hamwi) were developed primarily for medical calculations — specifically drug dosing — where a single number is needed rather than a range. They were not intended to be fitness or beauty targets.

Limitations of all formulas:

• None account for age — older adults naturally carry more fat and have lower muscle mass, so a slightly higher BMI (22–27) may actually be protective in people over 65.
• None account for body composition — a 75 kg person who is 15% body fat is much healthier than a 75 kg person who is 35% body fat, even though their "ideal weight" is identical.
• Asian populations (including Indians) tend to have higher health risks at lower BMI thresholds. Indian health guidelines suggest considering overweight at BMI ≥23 and obese at BMI ≥25, which is lower than the standard WHO cutoffs.

Use this calculator as a starting point for awareness, not as a strict target. A sustainable, realistic approach to health is far more valuable than chasing a formula-derived number.

Reaching and Maintaining a Healthy Weight

If your current weight falls outside your healthy range, sustainable lifestyle changes are more effective than crash diets or extreme exercise. Here is evidence-based guidance:

• Calorie awareness without obsession: A moderate deficit of 300–500 calories per day leads to steady fat loss of 0.3–0.5 kg per week without muscle loss. Use the Calorie Calculator to find your TDEE, then eat slightly below it.
• Prioritise protein: Adequate protein (1.2–1.6 g per kg of body weight) preserves muscle during fat loss, keeps you fuller longer, and supports metabolic rate. Include eggs, paneer, dal, chicken, fish, or protein supplements at each meal.
• Strength training matters: Building muscle increases your basal metabolic rate and improves body composition even without weight loss. A 70 kg person with 30% muscle is healthier — and looks leaner — than the same weight at 20% muscle.
• Focus on food quality: Replace refined carbohydrates (white rice in excess, maida, sugar) with whole foods, fibre, and vegetables. Reduce ultra-processed foods and liquid calories (juices, sodas, alcohol).
• Sleep and stress: Poor sleep and chronic stress increase cortisol, which promotes fat storage particularly around the abdomen. 7–8 hours of sleep and stress management are as important as diet and exercise for weight.
• Set weight range goals, not single numbers: Aim to stay within your BMI-based range (the output of this calculator) rather than a fixed target. This is more sustainable and aligns with how your body naturally fluctuates daily.

Calculator Category

This tool belongs to Health Calculators. Browse similar tools for related calculations.