Unit & Everyday Converters
BMI Calculator
Calculate Body Mass Index with health category, ideal weight range, and BMR.
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The BMI Calculator computes your Body Mass Index — a widely used screening tool that indicates whether your weight falls within a healthy range for your height. BMI is calculated as weight (kg) ÷ height² (m²). Despite its simplicity, BMI is the primary screening criterion used by health insurance underwriters, government health programs, and clinical triage in India.
Our calculator also computes Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula — the most accurate available equation — giving you the number of calories your body burns at complete rest. This is the foundation of any diet or fitness plan: knowing your BMR helps you set realistic calorie targets for weight loss, maintenance, or muscle gain.
Indian and Asian populations have a higher metabolic risk at lower BMI thresholds than Western populations. The World Health Organization and Indian health guidelines suggest that the 'Overweight' category for Indians starts at BMI 23 (vs 25 in Western standards), and 'Obese' at 27.5 (vs 30). Our calculator uses the international thresholds but flags this important India-specific consideration.
How to use this utility
- Use the controls below—paste text, pick files, or adjust options as described on the tool.
- Click the main action button. Processing runs in your browser on this device.
- Download or copy the output. Check the processing note for any external services used by this operation.
Common use cases
- Initial screening for insurance applications requiring BMI declaration
- Tracking weight loss or gain progress over time
- Setting calorie targets using BMR for diet plans
- Understanding weight risk for diabetes, hypertension, and cardiovascular disease
- Verifying BMI eligibility for bariatric surgery (typically BMI > 37.5)
Tips for best results
- 1BMI is a screening tool, not a diagnosis — waist circumference and body fat % are better indicators
- 2For Indian adults, health risks begin at BMI 23 — target below 22.9 for optimal health
- 3Waist circumference above 90 cm (men) or 80 cm (women) indicates abdominal obesity regardless of BMI
- 4Athletes and bodybuilders may have high BMI due to muscle mass despite low body fat
- 5BMI is less reliable for children and the elderly — use growth charts and body composition measures instead
Frequently asked questions
- Is Konnect2Tools free?
- Yes. These in-browser tools are completely free to use with no account required for core functionality.
- Do my files leave my device?
- Browser document operations run locally, except where the operation uses an external service, such as AI summarisation. Read the processing note before using sensitive inputs.
- Is the BMI Calculator tool safe to use?
- Local operations process document content on your device. External-service operations may send inputs as described in the processing note. Keep originals and inspect the output.
- What is a healthy BMI for Indians?
- For Indian adults, health experts recommend maintaining BMI between 18.5–22.9. Unlike Western populations where 25+ is considered overweight, Indians are at elevated risk for type 2 diabetes, hypertension, and cardiovascular disease at BMI 23+. This is due to higher visceral fat accumulation at lower BMIs in South Asians.
- What is BMR and how is it used?
- Basal Metabolic Rate (BMR) is the calories your body burns at rest to maintain basic functions. Multiply BMR by your activity factor to get TDEE (Total Daily Energy Expenditure). Eat 500 kcal below TDEE to lose ~0.5 kg per week; eat at TDEE to maintain; eat 300–500 above TDEE to gain muscle mass.
- Is BMI accurate for everyone?
- No — BMI has limitations. Athletes have high muscle mass, pushing BMI into 'overweight' despite low fat. Elderly people may have normal BMI but high fat-to-muscle ratio (sarcopenic obesity). For more accuracy, combine BMI with waist-to-height ratio, DEXA body composition scan, or visceral fat measurement.
- Can I use this calculator for my child?
- BMI for children and adolescents is interpreted differently using age- and sex-specific percentiles, not fixed categories. For children under 18, consult a pediatrician or use the WHO/IAP growth charts specific to Indian children. The adult BMI categories in this calculator are not appropriate for minors.
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