How is ideal weight calculated?

The Broca formula: Male ideal weight(kg) = (height in cm - 80) × 0.7, Female = (height in cm - 70) × 0.6. The normal range is ±10% of the calculated value. The BMI method defines a healthy weight range as BMI 18.5-24.9.

What is the difference between Broca and BMI methods?

The Broca formula provides a single target value, while the BMI method provides a healthy weight range. Both are general references and individual variation is expected.

🎯 Ideal Weight Calculator

Estimate ideal weight range based on height

Height (cm)

Gender

Reference Weight (Broca)

63 kg

Normal range 56.7 - 69.3 kg

Broca Reference Weight

63 kg

Range 56.7-69.3

BMI Healthy Weight

53.5-72 kg

BMI 18.5-24.9

Ideal Weight Calculator Guide

This calculator estimates your ideal weight range using multiple internationally recognized scientific formulas based on your height. Enter your height and the system will calculate reference values using the BMI method, Modified Broca formula, Devine formula, Robinson formula, and Miller formula, then provide a comprehensive ideal weight range.

"Ideal weight" is a statistical concept representing the weight range associated with the lowest mortality for a given height. It's a reference baseline — muscular athletes or people with larger frames may exceed this range while still being perfectly healthy. Focus on body fat percentage and overall health rather than chasing a specific number.

Multiple Ideal Weight Formula Comparison

[Common Formulas and Their Characteristics]

1. **BMI Method (Most Widely Used)** - Formula: Weight = BMI × Height²(m) - Normal range: BMI 18.5-24 → Ideal weight = 18.5×height² ~ 24×height² - Pros: Internationally recognized, strongest correlation with disease risk - Cons: Doesn't distinguish muscle from fat - Example (170cm): 53.5kg - 69.4kg

2. **Modified Broca Formula** - Formula: (Height cm - 100) × 0.9 (men) or × 0.85 (women) - Pros: Simple to remember, accounts for sex differences - Example (170cm male): 63kg

3. **Devine Formula (Clinical Use)** - Formula: Men=50+2.3×(height-60 inches); Women=45.5+2.3×(height-60 inches) - Pros: Used for drug dosage calculations - Example (170cm/67 inches male): 65.4kg

4. **Miller Formula** - Formula: Men=56.2+1.41×(height-60 inches) - Better for shorter individuals

5. **Robinson Formula** - Formula: Men=52+1.9×(height-60 inches) - Suitable for average builds

[Why Do Different Formulas Give Different Results?] These formulas were developed from different population samples with different focuses. BMI focuses on disease risk, Broca aligns more with traditional aesthetics, Devine is clinically oriented. It's best to look at results from multiple formulas and use the middle range as your target rather than fixating on one number.

Healthy Weight Management Strategies

[How to Interpret Ideal Weight]

Ideal weight ≠ a mandatory target! Special considerations apply: - Athletes/frequent exercisers: High muscle mass may push weight above the ideal range while body fat is healthy - Large-framed individuals: Naturally higher bone density and skeletal weight - Older adults: Being slightly overweight (BMI 24-27) may actually reduce mortality risk - Pregnancy/breastfeeding: Weight gain is a normal physiological need

[Scientific Weight Management Principles] 1. Focus on body composition, not just weight — body fat %, waist circumference, and muscle mass matter more 2. Set realistic goals — start with losing 5%-10% of current weight as a first milestone 3. Be gradual — 0.5-1 kg per week is the healthiest rate 4. Use comprehensive metrics — include fitness indicators (how far you can run, push-ups, etc.) 5. Mental health — don't let a number on the scale affect your self-worth

[When Should You Pay Attention to Your Weight?] Start monitoring if you notice: - Waist circumference exceeding thresholds (men ≥90cm, women ≥85cm) — indicates excess visceral fat - Rapid weight gain (>5% in 6 months) - Signs of metabolic issues (easy fatigue, skin changes) - Family history of obesity-related diseases

This calculator is for reference only and does not constitute medical advice. Consult a doctor or nutritionist for concerns.

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Ideal Weight Calculator Guide

Ideal Body Weight (IBW) is a theoretical reference weight calculated from height and sex. It provides a general reference point for understanding where an individual's weight falls relative to statistical norms.

This calculator uses two methods: ① Broca modified formula: Simple and widely used for quick estimation ② BMI reverse calculation: Derives a healthy weight range from BMI 18.5-24.9

Both methods provide general reference values. Individual variation in muscle mass, bone structure, and body composition means that no single formula applies perfectly to everyone.

Ideal Weight Formulas

Method 1: Broca Modified Formula
Male reference weight(kg) = (height in cm - 80) × 0.7
Female reference weight(kg) = (height in cm - 70) × 0.6
Normal range = reference weight × (0.9 ~ 1.1)

Method 2: BMI Reverse Calculation
Lower bound = 18.5 × [height(m)]^2
Upper bound = 24.9 × [height(m)]^2

Example (175cm male):
Broca: (175 - 80) × 0.7 = 66.5kg, range 59.9-73.2kg
BMI: 18.5×1.75^2=56.7kg to 24.9×1.75^2=76.2kg

Other Ideal Weight Formulas

Several other formulas exist for estimating ideal weight:

① Devine Formula (1974): Male IBW = 50 + 2.3×(height in inches - 60) Female IBW = 45.5 + 2.3×(height in inches - 60) Originally developed for medication dosing.

② Robinson Formula: Male IBW = 52 + 1.9×(height in inches - 60) Female IBW = 49 + 1.7×(height in inches - 60)

③ Miller Formula: Male IBW = 56.2 + 1.41×(height in inches - 60) Female IBW = 53.1 + 1.36×(height in inches - 60)

④ Hamwi Formula: Male IBW = 48 + 2.7×(height in inches - 60) Female IBW = 45.5 + 2.2×(height in inches - 60)

All formulas are statistical averages. Individual factors such as muscle mass, bone density, and body type affect actual ideal weight.

Ideal Weight Calculation Examples

📋

Example 1: 175cm male Broca: (175 - 80) × 0.7 = 66.5 kg, range 59.9-73.2 kg BMI: 56.7-76.2 kg Both methods produce similar results. Example 2: 163cm female Broca: (163 - 70) × 0.6 = 55.8 kg, range 50.2-61.4 kg BMI: 49.2-66.0 kg

Limitations

💡

All ideal weight formulas are statistical averages with significant individual variation. Factors not accounted for: • Age (older adults may have different healthy weight ranges) • Bone structure (larger frames naturally weigh more) • Muscle mass (athletes may weigh more while being healthy) • Not applicable for pregnant/breastfeeding women Body fat percentage and waist circumference may be more meaningful indicators than weight alone.

Common Use Cases

- General reference for understanding weight status
- Setting initial weight management reference points
- Clinical medication dosing reference
- Nutrition planning baseline data

Method Comparison

Each method has strengths and limitations:

| Method | Strength | Limitation | |--------|----------|------------| | Broca | Simple, easy to remember | Less precise for very tall individuals | | Devine | Accounts for sex differences | Based on Western population data | | BMI range | WHO-endorsed, evidence-based | Provides a range, not a single value | | Body fat % | Most accurate body composition | Requires specialized equipment |

No single formula is definitive. Using multiple methods as reference points provides a more complete picture.

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