Health &amp; Fitness Calculators and Clinical Guides

Calculate your body mass index (BMI) instantly. Analyze clinical weight ranges with a live horizontal gauge.

Calorie Calculator

Calculate your BMR and TDEE using the modern Mifflin-St Jeor formula. Get tailored calorie targets for losing, maintaining, and gaining weight.

Water Intake Calculator

Calculate your ideal daily hydration requirements based on your body weight, activity level, and climate.

Pace Calculator

Calculate running pace, time, or distance with our 3-in-1 calculator. View live km/mile side-by-side conversions and instant race time predictions.

Due Date Calculator

Estimate your baby's arrival date, trace gestational milestones, and follow your week-by-week trimester timeline.

Intermittent Fasting Calculator

Calculate your 16:8, 18:6, 20:4, or OMAD fasting windows with a live real-time ticking countdown timer and visual 24h timeline.

GFR & Kidney Function Calculator

Calculate estimated GFR (eGFR) using the 2021 race-free CKD-EPI creatinine equation and evaluate clinical CKD stage bands instantly.

Sleep Cycle Calculator

Optimize your bedtime and waking schedule using 90-minute sleep cycles to wake up refreshed and energetic.

Pregnancy Weight Gain Calculator

Calculate personalized healthy pregnancy weight gain ranges week-by-week based on pre-pregnancy Body Mass Index and gestational timing.

Macro Calculator

Calculate your daily macronutrient gram targets (protein, carbs, fats) based on your TDEE, fitness goals, and customizable macro splits.

Creatine & Fitness Macro Calculator

Calculate daily creatine dosage (loading vs maintenance), hydration needs, BMR, TDEE, and fitness macronutrient splits based on ISSN guidelines.

In-Depth Guides & Formulas (11)

Evidence-Based Creatine Dosage & Fitness Macro Master Guide

Clinical ISSN creatine saturation protocols (loading vs maintenance), hydration volume requirements, TDEE math, and optimal muscle-building macros.

9 min readRead Guide

Intermittent Fasting Schedule Guide: How to Choose & Time 16:8, 18:6, and OMAD

Learn how to structure and time intermittent fasting windows (16:8, 18:6, OMAD). Discover meal timing, hydration rules, and live calculation tools.

9 min readRead Guide

How to Calculate Running Pace: Min/Mile & Speed Guide

Learn how to calculate running pace in min/mile or min/km. Discover split time math, speed conversions, race pace targets, and free tools.

How to Calculate Pregnancy Weight Gain: BMI Guide

Learn how to calculate healthy pregnancy weight gain targets by trimester. Discover IOM guidelines, pre-pregnancy BMI math, and free online tools.

How to Calculate Pregnancy Due Date: Naegele's Rule Guide

Learn how to calculate pregnancy due date using Naegele's rule, conception date, and ultrasound adjustments. Discover trimester timelines and free tools.

How to Calculate Sleep Cycles: Optimal Wake-Up Guide

Learn how to calculate sleep cycles for optimal wake-up times. Discover 90-minute REM cycles, sleep latency math, circadian rhythm tips, and free tools.

How to Calculate Calorie Deficit: Step-by-Step Guide

Learn how to calculate a safe calorie deficit for sustainable weight loss. Discover BMR, TDEE math, macronutrient splits, and free calorie tools.

How to Calculate Daily Calorie Needs for Weight Loss

Learn how to calculate your daily calorie needs for weight loss using Mifflin-St Jeor and Katch-McArdle equations. Get actionable diet guidance.

Running Pace Strategy Guide: Calculate Target Race Pace

Master race pacing strategy for 5K, 10K, half marathon, and marathon. Learn negative split math, grade adjustments, and pacing tools.

Is the "8 Glasses a Day" Water Rule Actually True?

Explore the scientific origins of the 8x8 hydration rule, how climate and activity change water needs, and how to calculate your daily intake.

How to Calculate BMI Accurately & Understanding Limitations

Learn how Body Mass Index is calculated using weight and height. Understand WHO categories, muscle mass variations, and waist-to-height ratio.