Category
Health & Fitness
BMI, calories, macros, pregnancy tools and more — evidence-based calculators for everyday health decisions.
Track body composition, daily calories, macros, pregnancy milestones, and cardio training zones with free browser-based health calculators. Every result includes the formula used, WHO or clinical references where applicable, and links to related tools like BMI, body fat, and TDEE — so you can understand the number, not just see it.
21 tools · Private · Browser-only
Featured calculators
Popular starting points for health & fitness homework and quick checks.
BMI Calculator
Body Mass Index from height and weight.
OpenBody Fat Calculator
Estimate body fat with the U.S. Navy method.
OpenTDEE Calculator
Total daily energy expenditure.
OpenCalorie Calculator
Daily calorie needs by activity level.
OpenPregnancy Calculator
Weeks pregnant and trimester.
OpenOvulation Calculator
Estimated fertile window.
OpenRecently added & popular
Guides & comparisons
BMI vs Body Fat: Which Metric Should You Use?
BMI is a quick screening tool based on height and weight, while body fat percentage reflects actual composition. Learn when each metric helps—and when it misleads.
How to Measure Waist-to-Hip Ratio (WHR)
A waist-to-hip ratio uses two tape measurements. Consistent technique matters more than chasing a single result.
Pregnancy Due Dates and Gestational Age: How Calendar Estimates Work
A due date is a useful pregnancy timeline estimate, not a prediction of an exact birth day. Learn how LMP, cycle length, and early ultrasound fit together.
Ovulation and Fertile Window: What a Calendar Estimate Can—and Cannot—Tell You
An ovulation calculator can help you understand a cycle pattern, but it cannot confirm ovulation, predict pregnancy, or replace reliable contraception.
Body composition
BMI Calculator
Body Mass Index from height and weight.
OpenBody Fat Calculator
Estimate body fat with the U.S. Navy method.
OpenLean Body Mass Calculator
Fat-free mass from height and weight.
OpenFFMI Calculator
Fat-free mass index for athletes.
OpenIdeal Weight Calculator
Reference weight ranges by height.
OpenWaist-to-Hip Ratio
Body-shape health indicator.
OpenCalories & nutrition
BMR Calculator
Basal metabolic rate at rest.
OpenTDEE Calculator
Total daily energy expenditure.
OpenCalorie Calculator
Daily calorie needs by activity level.
OpenCalorie Deficit Calculator
Targets for gradual weight change.
OpenProtein Intake Calculator
Daily protein target in grams.
OpenMacronutrient Calculator
Protein, carbs and fat targets.
OpenWater Intake Calculator
Daily hydration target.
OpenCardio
Pregnancy
Pregnancy Calculator
Weeks pregnant and trimester.
OpenPregnancy Weight Gain Calculator
Reference weight-gain range by pre-pregnancy BMI.
OpenDue Date Calculator
Estimated due date from LMP.
OpenPregnancy Conception Calculator
Estimated conception date.
OpenOvulation Calculator
Estimated fertile window.
OpenPeriod Calculator
Estimate your next period from cycle length.
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