BMI Calculator

About BMI Calculator

Designed for efficiency and accuracy, BMI Calculator calculate your Body Mass Index in metric or imperial units, with WHO category breakdown and healthy range guidance. Using it is a three-step job: 1) Switch between metric (cm/kg) or imperial (ft·in/lb), 2) Enter your height and weight, 3) You'll get your BMI number plus the WHO category (underweight, normal, overweight, obese). BMI Calculator is part of ProfitTool's calculators collection. Check the notice beside the tool for its processing and data-handling details.

BMI Calculator is a free, browser-based bmi from ProfitTool. Calculate your Body Mass Index in metric or imperial units, with WHO category breakdown and healthy range guidance. Review any usage notes shown on this page before relying on its availability. Review the tool's data-handling notice before entering sensitive information; some features store settings locally or contact external services.

Working alongside the BMR & Calorie Calculator? keep Zakat Calculator (Multi-Asset) open in a second tab.

How to use BMI Calculator

1. 1Switch between metric (cm/kg) or imperial (ft·in/lb).
2. 2Enter your height and weight.
3. 3You'll get your BMI number plus the WHO category (underweight, normal, overweight, obese).

Already used our Body Fat Calculator? try BMR & Calorie Calculator to finish the job.

Why this matters

Money and health decisions get made on rough mental maths far too often. Running the actual numbers takes thirty seconds and routinely changes the answer — whether that's a loan you shouldn't sign, a rate you should be charging, or a target you can realistically hit.

Popular Use Cases

• Case 1
  Model a loan, mortgage or credit-card payoff before signing anything.
• Case 2
  Track fitness targets — BMI, BMR, water intake, calories and body fat.
• Case 3
  Split bills, tips and shared expenses without the drama.
• Case 4
  Convert grades, GPAs and academic scores between systems.

Technical Limitations & Boundary Conditions

• BMI cannot differentiate between skeletal muscle mass and adipose fat tissue; athletes frequently index as overweight.
• Does not measure visceral fat distribution around abdominal organs.

Key Terms Explained

Principal

The original amount borrowed or invested, before any interest is applied.

APR

Annual Percentage Rate — the yearly cost of a loan including fees, which is what makes it comparable between lenders.

Compounding

Earning interest on previously earned interest. Frequency (monthly vs annually) meaningfully changes the total.

Amortisation

The schedule showing how each payment splits between interest and principal over the life of a loan.

Pro Tips & Best Practices

• Enter exact numbers — the calculator handles rounding at the end for accuracy.
• Check the displayed units, dates, and assumptions; currency selection may format values without converting them.
• Treat estimates as planning aids and verify tax, fee, health, and lending inputs with authoritative sources.

Body Mass Index (Quetelet Formula) Standard

The Body Mass Index (BMI) was formulated by Adolphe Quetelet as an anthropometric screening indicator to classify nutritional status and weight-related health risk categories across broad populations.

Metric System: BMI = Weight (kg) / [Height (m)]²
Imperial System: BMI = [Weight (lbs) / (Height (inches))²] × 703
WHO Categories: Underweight (<18.5) · Normal (18.5–24.9) · Overweight (25.0–29.9) · Obese (≥30.0)

Worked Step-by-Step Example

Height Squared = 1.78 × 1.78 = 3.1684 m²
BMI = 76 / 3.1684 = 23.99 kg/m²

Frequently Asked Questions