Ideal Weight, BMI, Ponderal Index (children), BSA, WHtR, Body Fat %, Body Density & Volume, BMR and TDEE.
Ideal body weight (IBW) estimates a healthy weight for a given height and sex. It is commonly used in clinical nutrition and pharmacology.
Two widely used formulas are shown here. The Devine formula (1974) is height- and sex-based. The Creff formula also takes age into account and is often preferred for adults over 25.
These are statistical averages only. Athletes with high muscle mass and older adults frequently fall outside these ranges while remaining healthy.
Devine: Men 50 + 0.91×(h−152.4) · Women 45.5 + 0.91×(h−152.4)
Creff: ((height − 100) + (age ÷ 10)) × 0.9
Devine differentiates by sex (no age).
Creff includes age (sex-independent).
All values in kg.
| Height | Devine | Creff (by age) | ||||||
|---|---|---|---|---|---|---|---|---|
| Men | Women | 20 yrs | 30 yrs | 40 yrs | 50 yrs | 60 yrs | 70 yrs | |
| 155 cm | 52.4 | 47.9 | 51.3 | 52.2 | 53.1 | 54.0 | 54.9 | 55.8 |
| 160 cm | 56.9 | 52.4 | 55.8 | 56.7 | 57.6 | 58.5 | 59.4 | 60.3 |
| 165 cm | 61.5 | 57.0 | 60.3 | 61.2 | 62.1 | 63.0 | 63.9 | 64.8 |
| 170 cm | 66.0 | 61.5 | 64.8 | 65.7 | 66.6 | 67.5 | 68.4 | 69.3 |
| 175 cm | 70.6 | 66.1 | 69.3 | 70.2 | 71.1 | 72.0 | 72.9 | 73.8 |
| 180 cm | 75.1 | 70.6 | 73.8 | 74.7 | 75.6 | 76.5 | 77.4 | 78.3 |
| 185 cm | 79.7 | 75.2 | 78.3 | 79.2 | 80.1 | 81.0 | 81.9 | 82.8 |
| 190 cm | 84.2 | 79.7 | 82.8 | 83.7 | 84.6 | 85.5 | 86.4 | 87.3 |
| 195 cm | 88.8 | 84.3 | 87.3 | 88.2 | 89.1 | 90.0 | 90.9 | 91.8 |
| 200 cm | 93.3 | 88.8 | 91.8 | 92.7 | 93.6 | 94.5 | 95.4 | 96.3 |
Devine (1974) – sex-specific, no age:
Men = 50 + 0.91 × (height − 152.4)
Women = 45.5 + 0.91 × (height − 152.4)
Creff – includes age, sex-independent:
((height − 100) + (age ÷ 10)) × 0.9
Body Mass Index is a simple height-to-weight ratio used worldwide as a screening tool. It is calculated as weight (kg) divided by height (m) squared.
BMI is useful at population level but has limitations: it does not distinguish fat from muscle and ignores fat distribution.
WHO categories: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), Obesity I (30–34.9), II (35–39.9), III (≥40).
Height across the top (columns), weight down the side (rows). Cells show BMI and are colored by WHO category.
| Weight \ Height | 150 | 155 | 160 | 165 | 170 | 175 | 180 | 185 | 190 |
|---|---|---|---|---|---|---|---|---|---|
| 50 kg | 22.2 | 20.8 | 19.5 | 18.4 | 17.3 | 16.3 | 15.4 | 14.6 | 13.9 |
| 55 kg | 24.4 | 22.9 | 21.5 | 20.2 | 19.0 | 18.0 | 17.0 | 16.1 | 15.2 |
| 60 kg | 26.7 | 25.0 | 23.4 | 22.0 | 20.8 | 19.6 | 18.5 | 17.5 | 16.6 |
| 65 kg | 28.9 | 27.1 | 25.4 | 23.9 | 22.5 | 21.2 | 20.1 | 19.0 | 18.0 |
| 70 kg | 31.1 | 29.1 | 27.3 | 25.7 | 24.2 | 22.9 | 21.6 | 20.5 | 19.4 |
| 75 kg | 33.3 | 31.2 | 29.3 | 27.5 | 26.0 | 24.5 | 23.1 | 21.9 | 20.8 |
| 80 kg | 35.6 | 33.3 | 31.3 | 29.4 | 27.7 | 26.1 | 24.7 | 23.4 | 22.2 |
| 85 kg | 37.8 | 35.4 | 33.2 | 31.2 | 29.4 | 27.8 | 26.2 | 24.8 | 23.5 |
| 90 kg | 40.0 | 37.5 | 35.2 | 33.1 | 31.1 | 29.4 | 27.8 | 26.3 | 24.9 |
| 95 kg | 42.2 | 39.5 | 37.1 | 34.9 | 32.9 | 31.0 | 29.3 | 27.8 | 26.3 |
| 100 kg | 44.4 | 41.6 | 39.1 | 36.7 | 34.6 | 32.7 | 30.9 | 29.2 | 27.7 |
| 105 kg | 46.7 | 43.7 | 41.0 | 38.6 | 36.3 | 34.3 | 32.4 | 30.7 | 29.1 |
| 110 kg | 48.9 | 45.8 | 43.0 | 40.4 | 38.1 | 35.9 | 34.0 | 32.1 | 30.5 |
Underweight (<18.5) Normal (18.5–24.9) Overweight (25–29.9) Obesity I (30–34.9) Obesity II (35–39.9) Obesity III (≥40)
The Ponderal Index (also called Rohrer’s Index or Corpulence Index) is particularly useful for assessing body mass in infants, toddlers and young children. Unlike BMI, it uses the cube of height, which better reflects the three-dimensional growth of small bodies.
It is commonly used in neonatology and pediatrics to evaluate whether a newborn or young child is appropriately proportioned (especially in cases of intrauterine growth restriction or macrosomia).
Formula: Ponderal Index = Weight (kg) ÷ [Height (m)]³
Approximate interpretation for children (indicative only):
• < 11 → Low (thin / undernourished tendency)
• 11 – 15 → Normal range
• > 15 → High (higher body mass)
Always interpret results with a pediatrician.
Body Surface Area is the measured or calculated surface of the human body. It is widely used in medicine for dosing chemotherapy, calculating cardiac index, and determining fluid requirements.
Direct measurement is impractical, so prediction formulas are used. The Mosteller formula is simple and accurate for most adults. The older Du Bois formula remains common in many clinical protocols.
Average BSA is roughly 1.7–1.9 m² for adult men and 1.5–1.7 m² for adult women, but values vary significantly with height and weight.
Mosteller: √((height_cm × weight_kg) / 3600)
Du Bois: 0.007184 × weight0.425 × height0.725
Waist-to-Height Ratio is a simple and powerful indicator of central obesity and cardiometabolic risk. It is calculated by dividing waist circumference by height (both in the same unit).
A widely accepted rule of thumb is: “Keep your waist to less than half your height” (WHtR < 0.5). Research shows WHtR often predicts health risks better than BMI alone because it focuses on abdominal fat.
Measure your waist at the midpoint between the lowest rib and the top of the hip bone (or at the navel). Stand relaxed and do not suck in your stomach.
Healthy target: WHtR < 0.50. Values ≥ 0.50 indicate increased risk; ≥ 0.60 indicate substantially higher risk.
Body fat percentage estimates the proportion of fat mass relative to total body weight. It is generally more informative than BMI for assessing health and fitness.
Bioelectrical Impedance Analysis (BIA) is one of the most common practical methods. A small electrical current is passed through the body. Fat resists the current more than lean tissue, allowing an estimate of body composition. BIA is fast and affordable but sensitive to hydration, recent meals and exercise.
Dual-Energy X-ray Absorptiometry (DEXA/DXA) uses two low-dose X-ray beams to distinguish bone, fat and lean soft tissue. It is widely considered the clinical reference method for whole-body composition and also measures bone density. It is fast (5–10 min) and highly reproducible, though it involves a very small amount of radiation and is less precise for visceral fat than MRI.
Magnetic Resonance Imaging (MRI) provides the highest accuracy for regional fat distribution (especially visceral and ectopic fat) and muscle volume. Using specialized sequences (e.g. Dixon), MRI can separate fat and water signals with excellent soft-tissue contrast and no ionizing radiation. It is mainly a research and specialized clinical tool because of cost, time and limited availability.
| Feature | MRI | DEXA | BIA |
|---|---|---|---|
| Whole-body fat accuracy | Excellent | Very good | Moderate |
| Visceral fat accuracy | Excellent | Limited | Poor–moderate |
| Muscle quantification | Excellent | Good | Estimated |
| Radiation | None | Very low | None |
| Cost & access | High / low | Moderate | Low |
| Speed | Slow | Fast | Very fast |
| Best for | Research, detailed regional analysis | Clinical whole-body + bone | Everyday tracking |
Because true BIA, DEXA or MRI hardware is not available in a web page, this calculator offers two validated prediction methods: a quick BMI + age estimate and the US Navy circumference method.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5 % | 10–13 % |
| Athletes | 6–13 % | 14–20 % |
| Fitness | 14–17 % | 21–24 % |
| Average | 18–24 % | 25–31 % |
| Obese | ≥ 25 % | ≥ 32 % |
These are prediction equations. For the highest accuracy consider professional DEXA or MRI; for convenient tracking use high-quality multi-frequency BIA under consistent conditions.
Body density (usually expressed in g/cm³) is the mass of the body divided by its volume. Because fat is less dense than muscle and bone, lower whole-body density indicates higher body fat percentage.
Classic methods to measure body density:
Once density is known, it is converted to body fat percentage with one of two classic equations:
You can also calculate body volume directly from weight and density:
Volume (L) = Weight (kg) ÷ Density (g/cm³)
This works because 1 g/cm³ = 1 kg/L.
Typical density range for adults: ≈ 1.00–1.10 g/cm³.
Volume (L) = Weight (kg) ÷ Density (g/cm³). Also shown in litres and cubic metres.
BMR is the number of calories your body needs at complete rest to maintain vital functions. It usually represents 60–75 % of total daily energy expenditure.
The Mifflin-St Jeor equation is currently one of the most accurate prediction formulas for healthy adults.
BMR declines with age and is generally higher in men because of greater average lean mass. Building muscle raises BMR over time.
Mifflin-St Jeor: Men 10×wt + 6.25×ht − 5×age + 5 · Women 10×wt + 6.25×ht − 5×age − 161
TDEE is the total calories you burn in a day (BMR + activity + thermic effect of food). It is the most practical number for setting calorie targets.
It is estimated by multiplying BMR by an activity factor. Most people overestimate their activity level, so be honest with yourself.
For fat loss a moderate deficit of 300–500 kcal below TDEE is usually sustainable. For muscle gain a small surplus of 200–300 kcal works well with progressive training.