Online Health Tools

Free health calculators and utilities: BMI, body fat percentage, calories, hydration and more. Based on international medical standards.

BMI Calculator: Body Mass Index Online

Calculate your Body Mass Index (BMI) for free. Online tool to assess your nutritional status based on your weight and height, with visual scale and WHO categories.

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Color Blindness Simulator: Visualize Color Vision Deficiency

Simulate how people with color blindness perceive color. Visualize protanopia, deuteranopia, tritanopia and more with your own image or the included sample palette.

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Tinnitus Relief: Online Notch Therapy Tool

Free online tool for tinnitus relief through Notch Therapy. Customizable white, pink and brown noise generator with a notch filter at your exact tinnitus frequency.

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Conscious Breathing Visualizer: Box Breathing and Wim Hof Method

Instantly reduce stress and anxiety with our breathing visualizer. Bio-feedback guide for Box Breathing, 4-7-8 and Wim Hof Method.

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Caffeine Metabolism Tracker: Sleep Simulator

Calculate how much caffeine remains in your system based on your metabolism. Decay visualizer to avoid insomnia and improve your rest.

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Emergency Water Purifier

Bleach dosage calculator to purify emergency water. Survival tool based on WHO and CDC guidelines.

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Digestion Stopwatch: Physiological Transit Tracker

Calculate how long your food takes to digest. Track progress through the stomach, small intestine, and large intestine based on macronutrients.

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Binaural Wave Tuner for Lucid Dreams

Induce lucid dreams and deep relaxation states with delta, theta and alpha binaural beats. Frequency generator with visual stroboscope.

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Pelli Robson Contrast Sensitivity Test

Measure your visual contrast sensitivity with the Pelli Robson test. Diagnose your ability to detect shades of grey, essential for night driving and eye health.

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Peripheral Vision Trainer

Train your peripheral visual field with this agility game. Improve reading speed, situational awareness, and ocular reaction time.

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Epworth Sleepiness Scale Test

Measure your daytime sleepiness with the Epworth Sleepiness Scale. A clinically validated test to detect possible sleep disorders.

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Standard Drink Unit Calculator

Calculate the pure grams of alcohol and Standard Drink Units (SDU) of your cocktails, beer, wine and shots for safe and informed consumption.

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Ocular Decompression Rest Calculator

Calculate how many minutes of visual rest you need based on your daily screen time. Personalised 20-20-20 rule to prevent digital eye strain and fatigue.

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Blood Test Unit Converter

Medical calculator to convert blood test results between mg/dL and mmol/L. Compatible with glucose, total cholesterol, HDL, LDL, triglycerides, creatinine and urea.

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Optimal Reading Distance Calculator

Find out how many centimetres from the screen you should sit based on your font size. Avoid eye strain and protect your vision with ergonomics.

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Climate and Weight Hydration Calculator

Calculate exactly how much water you need to drink today. Algorithm adjusted for ambient temperature, relative humidity and physical activity level.

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What you will find in this category

BMI calculator with visual scale and WHO categories
Results based on verified medical algorithms
Completely free, no registration or tracking cookies
Full privacy: calculations happen on your device

# Science-Based Health Tools

Personal health is one of the areas where precise information makes a real difference. Our collection of online health utilities is designed to provide objective data, based on the standards of the World Health Organization (WHO) and other internationally recognized medical institutions.Unlike mobile apps that require access to personal data or device sensors, all these tools work directly in the browser. No health data leaves your device. No servers, no storage, no user profiles.

# Why a number is not everything

Health calculators offer an indicative reference, not a diagnosis. The Body Mass Index, for example, is a useful statistical screening tool for the general population, but it does not differentiate between muscle tissue and body fat. An elite athlete may have a technically elevated BMI without presenting any metabolic health problems.
Important medical disclaimer
All tools in this category are informational and educational in nature. They do not replace the judgment of a healthcare professional under any circumstances. If you have concerns about your health, always consult your doctor or specialist.

# Fundamentals of Health Metrics

  • BMI (Body Mass Index): Weight/height ratio. WHO screening indicator to classify nutritional status in adults.
  • Privacy by design: Calculations performed exclusively on the client. No telemetry, no tracking cookies, no personal data analysis.
  • International standards: The ranges and thresholds used correspond to guidelines published by the WHO and reference medical bodies.