Ideal Weight Calculator

Ideal Weight Calculator

Calculate your estimated ideal body weight range using multiple validated clinical equations locally inside your web browser. Unlike BMI, which only measures weight relative to height, ideal weight formulas produce an absolute weight target in kilograms, giving you a concrete number to work toward.

Mathematical Formula & Standards

Three widely cited ideal weight formulas exist, each developed from different population studies:

1. 1Devine Formula (1974) — Primary:
2. 2Male: IBW = 50 + 2.3 * (Height_{inches} - 60)
3. 3Female: IBW = 45.5 + 2.3 * (Height_{inches} - 60)

Originally developed for drug dosing calculations. Height above 5 feet (60 inches) adds 2.3 kg per inch.

1. 2Robinson Formula (1983):
2. 2Male: IBW = 52 + 1.9 * (Height_{inches} - 60)
3. 3Female: IBW = 49 + 1.7 * (Height_{inches} - 60)

1. 3Miller Formula (1983):
2. 2Male: IBW = 56.2 + 1.41 * (Height_{inches} - 60)
3. 3Female: IBW = 53.1 + 1.36 * (Height_{inches} - 60)

The tool converts your height in centimetres to inches internally (1 cm = 0.3937 inches) before applying all three formulas.

[Gender + Height (cm)]
        |
        v
[Height converted to inches]
        |
        v
[Devine / Robinson / Miller Equations]
        |
        v
[Ideal Weight Range in kg across all three formulas]

Input Methodology

1. 1Select Gender: Choose male or female (the formula constants differ between sexes).
2. 2Enter Height: Input your height in centimetres.
3. 3Review Results: See ideal weight estimates from all three formula models.
4. 4Use the Range: Treat the spread across all three outputs as your evidence-based target range.

Ideal Weight Calculator — Devine & Robinson Formula Estimator

This utility estimates ideal body weight using the Devine formula (the most widely used in clinical pharmacology) and the Robinson formula, providing a weight range rather than a single point value. It takes your gender and height (cm) as inputs and outputs ideal weight estimates across multiple models so you understand the range of evidence-based targets.

• Output Seems Very Low: Verify height is entered in centimetres. Entering 1.75 (metres) instead of 175 (centimetres) produces an extremely low ideal weight output.
• Formula Does Not Apply Below 152 cm: If you are shorter than 5 feet, consult a healthcare provider for height-specific guidance as these formulas were not validated for that range.
• Results Differ From Other Tools: Different ideal weight calculators use different formula selections. Devine is the most common; some tools use Hamwi (a different formula not used here).

Why are there multiple ideal weight formulas?

Each formula was derived from a different population study in a different decade. No single formula is universally accurate across all body types, ethnicities, and ages. Showing all three gives a realistic range rather than false precision from one number.

Does ideal weight account for muscle mass?

No. All ideal weight formulas use only height and sex as inputs. A heavily muscled person can appear overweight relative to the ideal weight formula while having low body fat. Use the Body Fat Calculator to assess composition separately.

Why does the Devine formula appear in pharmaceutical dosing?

Creatinine clearance formulas (Cockcroft-Gault) use ideal body weight rather than actual weight to prevent overdosing patients who are obese, since creatinine clearance tracks lean body mass, not total weight. This makes the Devine formula one of the most clinically consequential fitness equations in medicine.

Is my health data stored anywhere?

No. All calculations run client-side in your local browser.

• BMI Calculator: Calculate your Body Mass Index (BMI) instantly based on weight and height.
• Calorie Calculator: Determine daily calorie targets for weight maintenance, loss, or gain.
• BMR Calculator: Determine your Basal Metabolic Rate (BMR) using Mifflin-St Jeor formula.
• Water Intake Calculator: Calculate standard daily hydration requirements relative to weight and exercise load.
• Body Fat Calculator: Estimate body fat percentage using US Navy circumference methodologies.
• Protein Intake Calculator: Calculate standard daily protein guidelines for body composition goals.

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