Health Tools
Simple health calculators and reference tools. Tools are free to use with no account required. Most calculations run directly in your browser.
Free health and fitness calculators for body mass, calorie needs and body composition. Methods and limitations are explained with references to internationally recognised sources including WHO, CDC, NIH/NIDDK and peer-reviewed research.
Compare the health estimates
Weight relative to height
BMI is a quick screening reference, not a diagnosis or direct measure of body fat.
BMI CalculatorBody composition estimate
Use circumference measurements to estimate body-fat percentage.
Body Fat CalculatorRelated guides
All guides →Use health estimates as screening information
The BMI calculator, body-fat calculator and calorie calculator estimate different aspects of body size or energy needs. They are not interchangeable: BMI uses height and weight, circumference formulas approximate body composition, and calorie equations estimate daily energy expenditure from population averages.
Track trends, not isolated readings
Hydration, measurement technique, clothing, time of day and the formula selected can change a result. When monitoring progress, use the same method under similar conditions and look for a trend over several measurements rather than reacting to one number.
Know when to seek professional advice
These tools do not diagnose illness, assess nutritional deficiency or replace individual medical care. Speak with an appropriately qualified healthcare professional when results concern you, symptoms are present, pregnancy or an eating disorder is relevant, or a medical condition or medication affects weight, body composition or energy requirements.
Health Tools FAQ
Are these health tools free?
Yes. ToolBullet tools are free to use with no account, no download and no sign up required.
Do these tools store my data?
No. ToolBullet tools are designed to run in your browser. Inputs are not sent to a ToolBullet database or saved to an account.