IMC Calculator
IMC, or Índice de Masa Corporal, is the Spanish and French term for Body Mass Index (BMI). This free IMC calculator uses the standard formula to estimate body fat based on your weight and height. Enter your details below to get your IMC score and see which weight category you fall into.
How Is IMC Calculated?
The formula for IMC calculation is identical worldwide. For metric units:
IMC = weight (kg) ÷ height² (m²)
For imperial units:
IMC = weight (lb) ÷ height² (in²) × 703
Example: A person weighing 70 kg and 1.75 m tall has an IMC of 70 ÷ (1.75 × 1.75) = 22.9, which falls in the healthy range.
The calculator above performs this math automatically for both unit systems. It accepts metric (kilograms, centimetres) or imperial (pounds, feet/inches) measurements and returns your IMC value together with the corresponding weight category.
IMC Categories and Their Meaning
Based on World Health Organization (WHO) guidelines, the standard IMC ranges for adults aged 20 and older are:
| IMC Value | Weight Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal (healthy) weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity |
These thresholds apply regardless of gender. For the same IMC, women tend to carry more body fat than men, while older adults often have more fat than younger adults at the same IMC.
Why Use an IMC Calculator?
Your IMC score is a quick screening tool used by health professionals. Research links both low and high IMC values to increased health risks:
- Underweight (IMC below 18.5) may indicate malnutrition, weakened immune function, or underlying conditions.
- Overweight and obesity (IMC 25 and above) are associated with higher chances of heart disease, type 2 diabetes, and joint problems.
A single IMC measurement is not a diagnosis, but it can prompt a conversation with a healthcare provider about lifestyle changes or further testing.
Limitations of the IMC Calculation
The IMC calculator provides an estimate, not a definitive measure of health. Several factors can affect its accuracy:
- Muscle mass – Muscle is denser than fat. Athletes and muscular individuals may have an IMC in the overweight range despite low body fat.
- Fat distribution – The calculator ignores where fat is stored. Abdominal fat carries greater health risks than fat on hips or thighs.
- Age – In older adults, a slightly higher IMC (25–27) may be associated with better outcomes in some studies, challenging strict thresholds.
Use the calculator as a starting point. Waist circumference, body fat percentage, and medical history offer a more complete picture.
Disclaimer: This tool is for informational purposes only and is not a substitute for professional medical advice.