Health calculators that help — not lecture.
Calm, plain-English tools for the everyday questions about your body and activity. Each calculator gives you a clear number plus the context to understand it — gently, and without medical jargon.
Featured
Start with our most-used health tools
By use case
What are you curious about?
Tools grouped around everyday questions, not clinical categories. Pick the one that sounds most like you today.
Body basics
Quick snapshots of your body — useful starting points, not diagnoses.
BMI Calculator
Body Mass Index with a clear healthy-range guide.
Health →Body Fat Calculator
Estimate body fat percentage from a few measurements.
Health →Ideal Weight Calculator
Healthy weight ranges from trusted clinical formulas.
Health →Body Type Calculator
Find your general body type and what it means.
Health →Energy & nutrition
How much your body burns, how much it needs, and how to fuel it well.
Calorie Calculator
Daily calorie needs based on goals and activity.
Health →BMR Calculator
Basal metabolic rate — calories your body burns at rest.
Health →Macro Calculator
Daily protein, carbs, and fat targets for your goal.
Health →Water Intake Calculator
How much water to drink based on body and activity.
Health →Fitness & activity
Pace, steps, training zones, and recovery — for everyday movement and goals.
Pace Calculator
Running pace, time, and distance — solve for any one.
Health →Steps to Calories
Convert daily steps into calories and distance.
Health →Target Heart Rate
Training zones from resting and max heart rate.
Health →Sleep Cycle Calculator
Best bedtimes and wake times based on 90-min cycles.
Health →Pregnancy & fertility
Gentle, evidence-based estimates for due dates, weeks, and fertile windows.
Pregnancy Calculator
Pregnancy timeline from your last period or due date.
Health →Due Date Calculator
Estimate your due date with multiple methods.
Health →Pregnancy Week Calculator
What week and trimester of pregnancy you're in.
Health →Conception Calculator
Estimate the most likely date of conception.
Health →Ovulation Calculator
Predict your fertile window and ovulation day.
Health →Learn
Plain-English health explainers
Short reads that pair with the calculators above — written to inform, never to alarm.
What BMI does (and doesn't) tell you
A useful number for big-picture trends, but it can't see muscle, bone, or context.
Open BMI CalculatorHow many calories do you actually need?
BMR, activity, and goals — the three numbers behind a sensible daily target.
Open Calorie CalculatorHow much water is enough?
Why the '8 glasses' rule misses the point — and what to drink instead.
Open Water Intake CalculatorReading a pregnancy due date
Why due dates are a 5-week window, not a deadline — and what changes them.
Open Due Date CalculatorCalm by design
Numbers are framed in plain language with healthy ranges, never red alerts or scary labels.
Not medical advice
These tools are for orientation and learning. For anything that matters, talk to a clinician.
Private by default
Your inputs stay on your device. We don't store, sell, or upload what you type into the calculators.
Calcxo's health calculators are general-purpose tools to help you understand common metrics. They aren't a substitute for medical care, diagnosis, or treatment. If something about your health worries you, please reach out to a qualified healthcare professional.