BMI vs Body Fat: What Is the Difference?
BMI and body fat percentage are both used to assess health, but they measure very different things.
What BMI Measures
BMI (Body Mass Index) is simply your weight divided by your height squared. It does not know whether your weight comes from muscle, fat, water, or bone.
BMI = weight (kg) ÷ height (m)²
A BMI of 25 for a muscular athlete and a BMI of 25 for a sedentary office worker mean completely different things in terms of health risk.
What Body Fat Percentage Measures
Body fat percentage tells you what fraction of your total weight is fat tissue. This is far more useful for health assessment because it is excess fat — particularly visceral fat around organs — that increases disease risk.
| Category | Men | Women |
|---|---|---|
| Essential fat | 2-5% | 10-13% |
| Athletic | 6-13% | 14-20% |
| Fit | 14-17% | 21-24% |
| Average | 18-24% | 25-31% |
| Obese | 25%+ | 32%+ |
Why BMI Can Be Misleading for Indians
Research consistently shows that South Asians carry more visceral fat at lower BMIs than Western populations. This means an Indian person with a BMI of 23 may have the same health risk as a European with a BMI of 25-27.
This is why some health organisations suggest lower BMI cutoffs for Asian populations: - Normal: 18.5–22.9 (instead of 18.5–24.9) - Overweight: 23–24.9 (instead of 25–29.9) - Obese: 25+ (instead of 30+)
Which Should You Track?
Ideally, both. BMI is free and easy to calculate. Body fat percentage requires special tools (calipers, DEXA scan, bioimpedance scales) but gives you more actionable information.
For practical daily tracking, focus on: 1. Waist circumference — a simple tape measure around your belly at navel level. Above 90cm for men and 80cm for women indicates increased risk. 2. Weight trends — track weekly, not daily 3. How your clothes fit — often the most honest indicator
Calculate your BMI with our BMI calculator and track body measurements in our tracker.