Starlight Tools

Starlight Tools directory

Health & Fitness Tools

25 free, browser-based tools. No account required.

Free browser-based health and fitness calculators for BMI, body surface area, corrected calcium, body fat, BMR, TDEE, protein intake, VO2 max, heart health, hydration, growth percentiles, and running pace—all private and client-side. Try our BMI Calculator, Body Surface Area Calculator, Protein Intake Calculator, Corrected Calcium Calculator, or VO2 Max Estimator.

Health and fitness BMI calculator inputs for height weight and category gauge

BMI Calculator

Calculate your Body Mass Index (BMI) using imperial or metric units. v1.0

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Body surface area calculator with a star mascot, measuring tape, height ruler, and scale

Body Surface Area Calculator

Estimate BSA from height and weight with Mosteller, Du Bois, and Haycock formulas, then compare the results. v1.0

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Health and fitness BMI vs body fat percentage calculator comparing US Navy and Deurenberg estimates

BMI vs Body Fat %

Compare BMI with body fat % using US Navy & Deurenberg methods — metric/imperial, friendly categories, mini chart. v1.0

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Waist-to-hip ratio calculator with a star mascot, measuring tape, torso guide, and ratio gauge

Waist-to-Hip Ratio Calculator

Calculate WHR in centimetres or inches and compare it with WHO adult screening cutoffs, with clear measurement guidance. v1.0

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Army body composition waist-to-height ratio calculator

Army Body Fat Calculator

Check the current 2026 Army waist-to-height ratio standard, cutoff, and margin with metric or imperial measurements. v1.0

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Health and fitness BMR calculator showing basal metabolic rate formulas and TDEE multipliers

BMR Calculator

Estimate Basal Metabolic Rate via Mifflin–St Jeor, Harris–Benedict, Katch–McArdle & Schofield — with TDEE multipliers. v1.0

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Health and fitness Calorie TDEE calculator with maintenance and goal calories using activity multipliers

Calorie (TDEE) Calculator

Estimate daily maintenance & goal calories with activity multipliers — 100% client-side. v1.0

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Protein intake calculator with a star mascot, protein foods, shaker bottle, and dumbbell

Protein Intake Calculator

Estimate daily and per-meal protein by weight, goal, activity, and age group, with metric and imperial units. v1.0

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Health and fitness Calories burned calculator inputs for activity type weight and duration using MET values

Calories Burned by Activity

Pick an activity, enter weight and time, and see kcal burned using MET values. Private, client-side. v1.0.0

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Health and fitness Ideal weight calculator showing Broca Devine Hamwi and Robinson results with frame size

Ideal Weight Calculator

Estimate ideal body weight with Broca, Devine, Hamwi, and Robinson formulas. Metric & imperial, frame-size tweak. v1.0.0

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Health and fitness Blood pressure zone calculator classifying systolic and diastolic readings with ACC AHA and NICE thresholds

Blood Pressure Zone Calculator

Classify clinic, home, or ambulatory readings using ACC/AHA & NICE thresholds with a calm zone bar. v1.0.0

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Health and fitness Blood sugar HbA1c converter between NGSP IFCC and estimated average glucose mg dL mmol L

Blood Sugar / HbA1c Converter

Convert HbA1c (NGSP % ↔ IFCC mmol/mol) and estimated average glucose (eAG) in mg/dL ↔ mmol/L. v1.0.0

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Health and fitness Cholesterol ratio and risk calculator for total HDL LDL non HDL and AIP

Cholesterol Ratio & Risk Calculator

Compute Total/HDL, LDL/HDL, Non-HDL, and AIP with a gentle, private-by-design interface. v1.0.0

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Corrected calcium calculator with a star mascot, calcium sample, and albumin adjustment

Corrected Calcium Calculator

Calculate albumin-corrected total calcium in mg/dL or mmol/L, with formula limitations and local copy or CSV controls. v1.0

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Health and fitness Child growth percentiles tool showing CDC and WHO curves for weight length height BMI head circumference

Child Growth Percentiles (CDC & WHO)

Calm, private percentiles for weight, length/height, BMI and head circumference. WHO 0–5y and CDC 2–20y. v1.0.0

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Health and fitness Water intake calculator estimating daily hydration needs from weight exercise climate and altitude

Water Intake Calculator

Estimate daily hydration needs from weight, exercise, climate & altitude — plus pregnancy/lactation options. v1.0.0

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Heart beats counter showing lifetime beats and animal comparisons

Heart Beats Counter

Estimate daily, yearly, and lifetime heartbeats, see beats saved by lower bpm, and compare to animals with wildly different heart rates. v1.0

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QTc calculator with a star mascot, heart, ECG waveform, and clock

QTc Calculator

Compare Bazett, Fridericia, Framingham, and Hodges corrected QT estimates using heart rate or RR interval. v1.0

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Respiratory rate counter with a star mascot, lungs, breathing lines, and stopwatch

Respiratory Rate Counter

Count breaths with a 30- or 60-second timer, or convert a manual count to breaths per minute. Private and client-side. v1.0

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Heart rate zone calculator with a star mascot, heart monitor, and exercise zones

Heart Rate Zone Calculator

Calculate target exercise BPM and five training zones using age, measured maximum heart rate, or heart-rate reserve. v1.0

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Peak flow zone calculator with a star mascot, peak flow meter, lungs, and green yellow red zones

Peak Flow Zone Calculator

Calculate green, yellow, and red peak-flow ranges from a personal best and classify an optional current reading. v1.0

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Health and fitness One rep max calculator with weight and reps inputs using Epley Brzycki and Lombardi formulas

1RM Calculator

Estimate your one-repetition max using Epley, Brzycki, and Lombardi formulas. v1.0

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Health and fitness Race split planner showing even and negative split tables for 5K 10K half marathon and marathon

Race Split Planner

Plan even or negative splits for 5K/10K/Half/Marathon with per-km/mi tables and CSV export — 100% client-side. v1.0

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Health and fitness Pace speed time calculator converting between pace speed distance and time for running

Pace / Speed / Time Calculator

Enter any two (pace, speed, time, or distance) and compute the third. Km/mi aware, instant conversions. v1.0

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VO2 max estimator showing an aerobic capacity result from Cooper Rockport and heart-rate methods

VO2 Max Estimator

Estimate aerobic capacity from a Cooper run, Rockport walk, or measured heart-rate ratio, with metric and imperial inputs. v1.0

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About These Health & Fitness Tools

These calculators run entirely in your browser—no uploads or sign-ups—covering body composition, metabolism, aerobic capacity, heart health, hydration, growth charts, and training metrics.

Popular picks include the BMI Calculator, Body Surface Area Calculator, VO2 Max Estimator, Calorie/TDEE Calculator, and Pace Calculator. Use them free anytime.