📏 Body Fat Calculator

Estimate your body fat percentage using BMI and age.

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What is Body Fat Calculator?

Body Mass Index tells you about weight relative to height, but it can't distinguish muscle from fat — which is exactly the gap this calculator tries to close. Using your existing BMI figure along with your age, it applies a well-known formula to estimate the percentage of your body weight that comes from fat, giving a quick screening number without needing calipers, scans, or special equipment.

Deurenberg Body Fat Formula

Men: Body Fat % = (1.20 × BMI) + (0.23 × Age) − 16.2
Women: Body Fat % = (1.20 × BMI) + (0.23 × Age) − 5.4

Worked Example

For a 30-year-old man with a BMI of 24:

Body Fat % = (1.20 × 24) + (0.23 × 30) − 16.2
Body Fat % = 28.8 + 6.9 − 16.2 = 19.5%

A reading around 19-20% typically falls in the "acceptable to fit" range for adult men, though exact healthy ranges vary somewhat by age and the reference chart used.

How to Use This Calculator

  1. Enter your BMI (use the BMI Calculator first if you don't already know it).
  2. Enter your age.
  3. Click Calculate to see your estimated body fat percentage.

Things to Keep in Mind

This is the Deurenberg equation, developed as a practical, equipment-free estimate — it's noticeably less precise than a DEXA scan, hydrostatic weighing, or skinfold calipers taken by a trained professional, and can misjudge body fat for very muscular individuals or those with unusual fat distribution. Indian body composition research has also noted that South Asian populations tend to carry higher body fat at the same BMI compared with Western populations, which is worth keeping in mind when interpreting your result. Use this figure as a rough screening tool and a way to track relative change over time, not as a diagnostic measurement — and consult a doctor before making health decisions based on it.

💡 Tip: Track this number every few months rather than obsessing over a single reading — the trend over time matters more than one estimate.

📅 Last reviewed: July 2026 · Formulas verified against RBI/SEBI/IT Dept guidelines.