About this tool
BMI (Body Mass Index) is a common way to estimate whether your weight is in a healthy range relative to your height. It is your weight in kilograms divided by the square of your height in metres, expressed in kg/m². Because it does not distinguish fat from muscle, treat it as a rough screening number, not a precise body-fat measurement.
Enter your height and weight to get your BMI value and category, along with estimates of your Basal Metabolic Rate (BMR) and daily calorie needs — useful for gauging how much to eat to maintain, gain or lose weight. Everything is calculated in your browser; your height and weight are never uploaded.
How to use
- Pick a unit system (metric cm/kg or imperial ft-in/lb).
- Enter your height and weight; add age, sex and activity level if you also want calorie estimates.
- Read the BMI value and its category (underweight / normal / overweight / obese).
- Use the BMR and daily-calorie suggestions below as a baseline, then adjust diet and exercise to your goal.
When to use it
- Quickly check whether your BMI sits in the normal range before or after a checkup.
- Estimate a daily calorie deficit or surplus when planning fat loss or muscle gain.
- Run a simple health self-check for adult family members.
- Track how your BMI trends over time in a fitness log.
FAQ
What are the standard BMI ranges?
Using the common WHO cutoffs: below 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30 or above is obese. Note that some regions (e.g. mainland China and several Asian guidelines) use stricter thresholds where 24 already counts as overweight.
Why does BMI read high for muscular people?
BMI only looks at total weight and cannot tell muscle from fat. Since muscle is denser than fat, athletes and lifters with low body fat can still be classed as "overweight". For them, body-fat percentage or waist measurement is more meaningful.
How are BMR and daily calorie needs estimated?
BMR is estimated with the widely used Mifflin-St Jeor formula from height, weight, age and sex — the calories your body burns at rest. Multiplying it by an activity factor gives your daily total (TDEE). These are estimates and vary between individuals, so use them as a starting point.
Is my data saved or uploaded?
No. Everything runs locally in your browser. Your height, weight and other inputs are neither uploaded nor stored, and they are cleared when you close the page.