🏥 Free Health Calculators
Simple, free tools to calculate BMI, calorie needs, metabolism, and other health-related estimates. Designed for everyday use on mobile and desktop.
This page is part of our broader calculator collection. You may also find our adult BMI calculator and child BMI calculator useful.
BMI Calculator
Calculate your Body Mass Index and healthy weight range for adults.
Child BMI Calculator
Check BMI-for-age percentile for children and teens ages 2 to 19 using CDC-based guidance.
BMR Calculator
Estimate how many calories your body burns at rest each day.
TDEE Calculator
Estimate your BMR, maintenance calories, and daily energy needs for weight management.
Child TDEE Calculator
Daily calorie needs for children and teens based on age and activity.
Calorie Calculator
Estimate daily calorie needs based on activity level and goals.
Water Intake Calculator
Estimate daily hydration needs based on weight and lifestyle.
Why Use Online Health Calculators?
Health-related calculations often involve formulas that are not easy to work out manually. Online health calculators help you estimate important values like body mass index, metabolic rate, and calorie needs in seconds. They are useful for general awareness, planning, and educational purposes.
Which Calculator Should You Use?
- BMI Calculator: Best for checking body mass index using height and weight. Useful for adults aged 18 and older.
- Child BMI Calculator: Use this tool for children and teens ages 2 to 19, where BMI is interpreted using age- and sex-specific percentiles rather than adult cutoffs.
- BMR Calculator: Helps estimate the calories your body needs at complete rest.
- Calorie Calculator: Helps estimate total daily calorie needs based on activity level and goals such as weight loss, maintenance, or gain.
If you’re unsure where to start, try the BMI calculator for adults first, or use the BMI percentile tool for kids and teens for anyone under 20.
How We Build Our Health Calculators
Our health calculators are based on widely used formulas and guidance from established medical and public health references. We aim to keep every tool simple, transparent, and easy to use across devices. You can read more about how we review formulas and update content on our Methodology and Editorial Policy pages.
Frequently Asked Questions
Are these health calculators accurate?
They are designed to provide general estimates using standard formulas. However, they do not replace professional medical evaluation.
What is the difference between BMI and BMR?
BMI is a height-weight screening measure, while BMR estimates how many calories your body burns at rest.
Can children use the adult BMI calculator?
No. Adult BMI categories should not be used for children and teens. A child BMI calculator uses age-specific percentiles.
Do these calculators replace a doctor’s advice?
No. These tools are for educational purposes only and should be used alongside professional healthcare guidance.