Premium Converters
Loading
Loading, please wait.
Loading
Loading
Calculate Body Mass Index against WHO and Asian-population thresholds for men and women using kg or lb, cm or inches, with healthy-range guidance.
Health
Generated on May 23, 2026
Calculate Body Mass Index against WHO and Asian-population thresholds for men and women using kg or lb, cm or inches, with healthy-range guidance.
Body Mass Index (BMI) is the most widely used screening metric in medicine for estimating whether a person's weight is healthy relative to their height. This calculator supports both metric (kg, cm) and imperial (pounds, inches) units and returns both the BMI value and the WHO category (underweight, healthy, overweight, obese). BMI is quick, non-invasive, and correlates strongly with body fat in the general adult population — which is why doctors, insurers, fitness trainers, and public-health agencies use it as a starting point for assessing weight-related health risk.
Formula
BMI = weight (kg) ÷ [height (m)]². Imperial version: BMI = (lbs ÷ in²) × 703.If you're checking your BMI, chances are someone — a doctor, a gym trainer, a wedding-ready cousin — already threw a number at you, and the line between "normal" and "overweight" felt strangely thin. Here's what most people don't realise: the standard BMI thresholds were built on European bodies, and the WHO themselves quietly recommend lower cutoffs for South Asian frames because the same number means more visceral fat for us. A BMI of 24 on a Punjabi or Gujarati body is not the same conversation as a BMI of 24 on a Dutch one. The formula also can't see muscle. If you've been lifting for a year, a BMI of 27 might sit on a healthier body than a sedentary 22. Run the number, then read it against the band that matches your population — and pair it with waist measurement, which catches the belly fat BMI quietly misses. Treat the result as the start of a conversation with your GP, not a verdict on your worth. The number is a screening tool. You are not the number.
Body Mass Index (BMI) is the most widely used screening metric in medicine for estimating whether a person's weight is healthy relative to their height. This calculator supports both metric (kg, cm) and imperial (pounds, inches) units and returns both the BMI value and the WHO category (underweight, healthy, overweight, obese). BMI is quick, non-invasive, and correlates strongly with body fat in the general adult population — which is why doctors, insurers, fitness trainers, and public-health agencies use it as a starting point for assessing weight-related health risk. It does not replace a medical consultation, but it identifies whether further evaluation is warranted.
BMI normalizes body weight against the square of height to approximate body-surface-area proportionality, giving a single number that correlates with adiposity across most adult populations regardless of their height. The coefficient 703 in the imperial version converts from pounds-per-inch-squared to the equivalent metric kg/m². This formula was developed by Belgian statistician Adolphe Quetelet in the 1830s and is still the standard clinical starting point for weight assessment, despite known limitations for athletic and elderly individuals.
Official WHO BMI classification and the healthy weight range (BMI 18.5–24.9) for common adult heights.
| BMI Range | Category | Height 5'4" (163 cm) | Height 5'7" (170 cm) | Height 5'10" (178 cm) | Height 6'1" (185 cm) |
|---|---|---|---|---|---|
| < 18.5 | Underweight | < 49 kg | < 53 kg | < 59 kg | < 63 kg |
| 18.5 – 24.9 | Healthy | 49 – 66 kg | 53 – 72 kg | 59 – 79 kg | 63 – 85 kg |
| 25.0 – 29.9 | Overweight | 66 – 79 kg | 72 – 86 kg | 79 – 95 kg | 85 – 102 kg |
| 30.0 – 34.9 | Obesity (Class I) | 79 – 93 kg | 86 – 101 kg | 95 – 111 kg | 102 – 120 kg |
| 35.0 – 39.9 | Obesity (Class II) | 93 – 106 kg | 101 – 115 kg | 111 – 127 kg | 120 – 137 kg |
| ≥ 40.0 | Obesity (Class III) | ≥ 106 kg | ≥ 115 kg | ≥ 127 kg | ≥ 137 kg |
WHO 'healthy' BMI (18.5–24.9) covers a ~16 kg range for a 170 cm adult — room for muscle, bone density, and natural variation.
A BMI of 25 is the global overweight threshold — but athletic adults often register as 'overweight' because muscle is denser than fat.
Asian populations face elevated diabetes/cardiovascular risk at lower BMIs — WHO suggests Asian cutoffs: overweight ≥ 23, obesity ≥ 27.5.
Waist-to-hip ratio and waist-to-height ratio are better predictors of health risk than BMI alone for individuals.
A 70 kg adult at 1.75 m has a BMI of 22.9 — squarely in the healthy range (18.5–24.9).
A 90 kg adult at the same height has a BMI of 29.4 — overweight and approaching the obese threshold.
In imperial units, 154 lbs at 69 inches (5 ft 9 in) gives a BMI of 22.8 — matching the metric result.
A 50 kg adult at 1.70 m has a BMI of 17.3 — classified as underweight and worth medical review.
A muscular gym-goer weighing 85 kg at 1.75 m has a BMI of 27.8 (overweight) despite very low body fat — a textbook BMI limitation.
A 60 kg adult at 1.60 m has a BMI of 23.4 — healthy, with a small cushion on either side before crossing category thresholds.
Jump to a ready-made conversion — useful for quick reference and sharing:
BMR Calculator
Estimate Basal Metabolic Rate using the Mifflin-St Jeor equation by sex, age, weight and height — the resting kcal/day baseline for diet planning.
TDEE Calculator
Compute Total Daily Energy Expenditure from BMR and activity multiplier (sedentary to extra active) to set kcal targets for cutting, maintenance, or bulking.
Ideal Weight Calculator
Find your ideal weight range in kg and lb using the Robinson, Miller, Devine and Hamwi formulas alongside the BMI 18.5-24.9 healthy band for men and women.
Water Intake Calculator
Calculate daily water intake in millilitres or litres from body weight and exercise minutes, with hot-climate, pregnancy and breastfeeding adjustments.
Body Fat Calculator
Estimate body fat percentage with the US Navy tape-measure method using neck, waist and hip in cm or inches — a no-cost alternative to DEXA scans for men and women.
Macro Calculator
Calculate your daily protein, carbohydrate, and fat targets based on your goals.
Pregnancy Due Date Calculator
Estimate baby's due date using Naegele's rule (LMP + 280 days), adjusted for cycle length, with conception date, trimester boundaries and current week and day.
Ovulation Calculator
Predict ovulation day and the six-day fertile window from your last menstrual period and cycle length for conception planning and natural family planning.
Browse all Health calculators & converters
See every tool in this category, plus FAQs and category-specific guides.