BMI Calculator
Calculate your BMI from height and weight. View body classification, standard weight, healthy weight range, and weight deviation.
Last updated:
How to Use
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- 1
Enter your height
Enter your height in centimeters (cm)
- 2
Enter your weight
Enter your weight in kilograms (kg). Age input is optional
- 3
Check the results
View your BMI value, body classification, standard weight, and healthy weight range
Body Data Input
Result
Enter height and weight to calculate BMI
About BMI Calculator
BMI Calculator computes your Body Mass Index from height and weight using the standard formula (weight in kg divided by height in meters squared), following World Health Organization (WHO) classification guidelines. Results include your BMI value with one decimal place, body classification (Underweight, Normal, Overweight, or Obese), standard weight for your height, healthy weight range (BMI 18.5–24.9), and the deviation from standard weight. An optional age input provides age-specific target BMI ranges, since recommended values shift as you age. All calculations run locally in your browser — no personal health data is ever transmitted to any server.
Key Features
- Real-time BMI calculation from height and weight
- WHO-based body classification
- Standard weight and healthy weight range display
- Weight deviation percentage from standard weight
Use Cases
- Reviewing results from your annual physical or wellness exam
- Setting a realistic target weight for a fitness or weight-loss goal
- Understanding which weight category you fall into (underweight, normal, overweight, obese)
- Tracking BMI changes over time alongside a diet or exercise program
- Checking whether your current weight falls within a healthy range for your height
Frequently Asked Questions
What is a healthy BMI range?
According to WHO guidelines, a BMI between 18.5 and 24.9 is considered normal weight. Under 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese.
How is standard weight calculated?
Standard weight is calculated as height (m) squared × 22. A BMI of 22 is considered statistically optimal for the lowest risk of disease.
What are the limitations of BMI?
BMI cannot distinguish between muscle mass and body fat, so it may not accurately reflect the physical condition of athletes or heavily muscled individuals. It should be used as a general guideline alongside other health indicators.
Does age affect the ideal BMI range?
Research suggests that the optimal BMI range may vary with age. Older adults may benefit from a slightly higher BMI to help prevent frailty and muscle loss (sarcopenia).
Is BMI the same as body fat percentage?
No. BMI is a simple ratio of weight to height and does not directly measure body fat. Two people with the same BMI can have very different body compositions. A DEXA scan or body composition analysis gives a more accurate picture of body fat.
Editorial Review & References
- Reviewed by
- Toolsbase Editorial Team
- Last reviewed
References
- WHO — Body mass index (BMI) international criteriaOpens in a new tab
- Japan Society for the Study of Obesity — Clinical Practice Guidelines for Obesity Disease 2022Opens in a new tab
- Ministry of Health, Labour and Welfare — Dietary Reference Intakes for Japanese (2025 edition) — target BMI values
- Aune D et al. (BMJ 2016) — BMI and all-cause mortality: meta-analysis of 230 cohort studies (3.74 million participants)
Disclaimer
BMI and obesity-degree values from this tool are provided for reference only. BMI is a simple indicator based solely on height and weight; it does not account for muscle mass, body fat percentage, bone density, age, pregnancy, or other factors. For actual health assessments or weight-management decisions, please consult a physician, registered dietitian, or other qualified healthcare professional.