BMI Calculator – Body Mass Index Tool
Calculate your BMI and instantly check if you're underweight, healthy, overweight, or obese.
Results
🧍 Overview: Body Mass Index (BMI) Calculator
The Body Mass Index (BMI) Calculator helps you quickly assess whether your weight falls within a healthy range based on your height, age, and gender. This tool uses the standard BMI formula and optionally integrates advanced metrics like body fat percentage, waist-to-hip ratio, and estimated TDEE (Total Daily Energy Expenditure) for a more complete picture.
Whether you're tracking your fitness journey, evaluating your health goals, or simply curious about your ideal weight, this BMI tool is fast, accurate, and fully optimized for both desktop and mobile use.
🧮 Formula & Methodology
Standard BMI Formula:
Metric: BMI = weight (kg) / [height (m)]² Imperial: BMI = (703 × weight (lbs)) / [height (in)]²
Advanced Mode: When enabled, the tool also estimates:
- Body Fat % using the US Navy Method
- TDEE (caloric needs) using Mifflin-St Jeor BMR estimation
🧾 Example Calculation
Scenario: 30-year-old female, 160 lbs, 65 inches tall (Imperial)
- BMI: (703 × 160) / (65 × 65) ≈ 26.62
- Classification: Overweight
- Advice: Incorporate more physical activity and adjust your diet.
- Ideal Weight Range: 110.5 – 147.5 lbs
- (Advanced Mode): Estimated TDEE ≈ 2242 kcal/day, Body Fat ≈ 33.5%
📊 BMI Classification Table
| BMI Range | Classification | Advice |
|---|---|---|
| Less than 18.5 | Underweight | Consider gaining weight through a nutrient-rich diet |
| 18.5 – 24.9 | Normal weight | Maintain your current lifestyle and nutrition |
| 25 – 29.9 | Overweight | Consider more exercise and dietary adjustments |
| 30 or more | Obese | Consult a health professional for personalized advice |
🔍 Common Use Cases
- 💪 Fitness Tracking: Monitor weight changes as part of your health journey
- 📊 Health Screening: Use as a preliminary check for weight-related risk factors
- 👨👩👧👦 Family Health: Assess BMI for teens and adults in the household
- 🧠 Educational: Teach students about body composition and health markers
❓ Frequently Asked Questions
What is BMI and how is it calculated?
BMI (Body Mass Index) is a number derived from your weight and height. It's calculated by dividing your weight in kilograms by your height in meters squared. In imperial units, it's (703 × weight in lbs) divided by height in inches squared.
How accurate is BMI?
BMI is a reliable general indicator, but it does not distinguish between fat and muscle. This is why our calculator includes advanced mode to estimate body fat percentage and caloric needs.
What’s a healthy BMI?
A BMI between 18.5 and 24.9 is considered healthy for most adults. However, body composition, age, and gender can influence what’s ideal for each person.
Can I use this BMI Calculator for children or teens?
While the calculator works for teens, BMI interpretation for those under 18 should consider age and gender growth percentiles. A pediatric BMI-for-age chart is recommended for children.
Does gender affect BMI?
The standard BMI formula is the same for both genders. However, because males and females typically have different muscle-to-fat ratios, our advanced mode includes gender-based calculations for better insights.
What is the US Navy Body Fat Formula?
It's an estimate of body fat % based on waist, neck, and (for women) hip measurements. It’s useful when you want more insight beyond the BMI number.
Check out Body Fat Percentage Calculator
How is TDEE calculated?
TDEE (Total Daily Energy Expenditure) is estimated from your BMR (calories burned at rest) and activity level. Our tool uses the Mifflin-St Jeor equation for BMR, then multiplies by an activity factor (default: 1.55).
Check out Basal Metabolic Rate (BMR) Calculator