Health & Fitness Calculators
Essential health and fitness metrics: Body Mass Index (BMI), Total Daily Energy Expenditure (TDEE), daily hydration, and sleep cycle timers.
Pregnancy Due Date & Gestational Age Calculator (Naegele's Rule, Conception & Trimesters)
Calculate estimated due date (EDD), gestational age in weeks and days, conception date, and trimester milestones using Naegele's rule, ultrasound dating, or IVF transfer.
Target Heart Rate Calculator & 5 Cardio Training Zones (Karvonen & Tanaka Formulas)
Calculate maximum heart rate (HRmax), resting heart rate reserve (HRR), and 5 cardiovascular training zones using the Karvonen, Tanaka, and Gellish formulas with live fat-burning analysis.
Blood Alcohol Concentration (BAC) Calculator & Sobriety Timeline (Widmark Formula)
Calculate your estimated Blood Alcohol Concentration (BAC), time to 0.00% legal sobriety, and impairment level using the scientific Widmark formula with customizable drink types and body weight.
BMI Calculator (Standard & Oxford New BMI with Waist-to-Height Ratio)
Calculate Body Mass Index (BMI), Oxford New BMI, Ponderal Index, and Waist-to-Height Ratio (WHtR) with WHO healthy weight ranges and metric & imperial units.
TDEE & Calorie Burn Calculator (Mifflin-St Jeor, Katch-McArdle & Goal Timeline)
Calculate your exact Total Daily Energy Expenditure (TDEE), BMR, calorie deficit targets, fat loss timeline, and custom macronutrient splits with scientific precision.
Daily Water Intake & Hydration Schedule Calculator (Clinical Osmolality & Pacing)
Calculate optimal daily fluid requirements in liters and ounces based on body weight, workout intensity, sweat rate, climate, and elevation with hourly pacing.
Sleep Cycle & Wake-Up Calculator (90-Minute REM & NASA Nap Architecture)
Calculate optimal bedtimes and wake-up times based on 90-minute REM ultradian cycles. Avoid sleep inertia, optimize circadian rhythm, and wake up refreshed.
US Navy Body Fat Calculator (Circumference Method & DoD Standards)
Calculate body fat percentage, lean body mass, fat mass, and military readiness using the official US Navy tape method (DoD 1308.3 standard) with metric & imperial units.
Macro Calculator (Protein, Carbs & Fat Split for Cutting, Bulking & Keto)
Calculate personalized daily macronutrient targets in grams, calories, and meal splits. Anchored by sports science protein floors, hormonal fat minimums, and glycogen demands.
Ideal Body Weight Calculator (Devine, Robinson, Miller & Hamwi Formulas)
Compare your ideal body weight across 4 medical standards (Devine, Robinson, Miller, Hamwi), bone frame size adjustments, and WHO healthy BMI ranges.
Caffeine Half-Life & Sleep Crash Decay Calculator (CYP1A2 Pharmacokinetics)
Track active caffeine levels in your bloodstream hour-by-hour using pharmacokinetic half-life and CYP1A2 metabolic speed. Find out when you can fall into deep sleep.
Sleep Deprivation & BAC Impairment Equivalent Calculator (PVT Reaction Test)
How impaired is your brain from sleep deprivation? Converts consecutive hours awake into equivalent Blood Alcohol Concentration (BAC) with an interactive reaction speed test.
ADHD Task Paralysis & Executive Dysfunction Chunking Tool
Break down overwhelming chores, work projects, and emails into tiny, 2-minute dopamine-accessible micro-steps to defeat ADHD executive dysfunction.
CBT Thought Challenger & Cognitive Distortion Diary (7-Column Beckian Record)
Free online Cognitive Behavioral Therapy (CBT) thought record. Identify 10 cognitive distortions, challenge automatic negative thoughts, and re-rate emotional distress.
Box Breathing & Vagus Nerve Pacer (Navy SEAL & Huberman Sigh)
Interactive somatic breath pacer with visual expanding guide and audio chime. Features Navy SEAL 4-4-4-4 Box Breathing and Huberman Physiological Sigh.
ADHD Time Blindness & Departure Buffer Calculator
Calculates the real time required for tasks and departures by factoring in ADHD transition tax, distraction buffers, and the prefrontal planning fallacy.
ADHD Dopamine Menu & Stimulus Selector
Interactive Dopamine Menu planner. Organize appetizers, entrees, sides, and desserts to stimulate prefrontal dopamine and break task paralysis.
Sensory Overload & 5-4-3-2-1 Somatic Grounding Tool
Interactive 5-4-3-2-1 sensory grounding exercise and burnout decompression checklist for neurodivergent sensory overload and panic spikes.
Adult ADHD Symptom Screener (WHO ASRS-v1.1 Checklist)
Interactive World Health Organization Adult ADHD Self-Report Scale (ASRS-v1.1). Screens for inattention and hyperactivity with printable clinical summary.
Stand On Your Own Feet: The Radical Self-Reliance & Motivation Engine
A no-bullshit motivational bombardment engine and self-reliance diagnostic. Hard-hitting stoic truths, continuous quote barrage, and 4 pillars of independence. 100% Ad-Free.
Evidence-Based Therapy Matcher & Clinical Self-Help Guide
Interactive clinical psychotherapy recommendation engine. Compare CBT, DBT, ACT, EMDR, and Somatic Experiencing to match your psychological needs. 100% Ad-Free.
Clinical Burnout Assessment & Depletion Index (Maslach MBI & WHO ICD-11)
Evaluate occupational burnout across Emotional Exhaustion, Cynicism/Depersonalization, and Professional Efficacy using the validated Maslach Burnout Inventory framework.
Imposter Phenomenon Diagnostic & Competence Auditor (CIPS)
Free Clance Imposter Phenomenon Scale (CIPS). Assess your level of intellectual fraud feelings, perfectionism, fear of failure, and attribution bias.
Cumulative Sleep Debt & Circadian Recovery Calculator (PVT & BAC Equivalence)
Calculate your accumulated 7-day sleep deficit, equivalent blood alcohol concentration (BAC) impairment, attention lapses, and safe 4-day recovery schedule.
Lifetime Screen Time Calculator (Years of Your Life Lost to Glass)
Calculate the exact continuous 24/7 years of your finite life spent staring at phone, computer, and TV screens. Features visual lifetime breakdown and dopamine detox protocols.
Adult Attachment Style & Relationship Trigger Diagnostic
Discover your adult attachment style: Secure, Anxious-Preoccupied, Dismissive-Avoidant, or Fearful-Avoidant (Disorganized). Based on Hazan & Shaver psychology.
Decibel Sound Dose & Hearing Damage Estimator (OSHA/NIOSH)
Calculate safe listening duration for headphones, concerts, and loud noise environments before permanent hearing loss occurs. Uses NIOSH 3dB and OSHA 5dB rules.
One-Rep Max Calculator (1RM) — Epley, Brzycki & 5/3/1 Load Table
Calculate your true one-rep max (1RM) across 7 clinical strength formulas (Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, Wathan), RPE exertion scale, and percentage working set table for barbell training.
Calorie Deficit Calculator — Target Weight Date & Metabolic Adaptation Predictor
Calculate your exact daily calorie deficit, estimated date to hit target weight, metabolic adaptation downregulation, and personalized macro split for safe fat loss.
Running Pace Calculator — Mile/Km Splits, Race Predictor & Training Zones
Calculate running pace, 5K/10K/Half/Full Marathon finish time splits, Riegel race predictions, and heart rate training zones (Zone 2 to VO2 max) with metric & imperial units.