16 calculators · every formula cited
Recovery calculators
Every recovery calculator, each built on a published, peer-reviewed formula, with the sources cited on the page.
Heart Rate Zone Calculator: Tanaka & Karvonen
The Tanaka equation (208 − 0.7 × age) and the Karvonen heart-rate-reserve method, with a full five-zone training table.
RecoverySleep Calculator: When To Go To Bed
Enter your wake-up time and get bedtime options for 4, 5 or 6 full 90-minute cycles, including 15 minutes to fall asleep.
RecoveryRunning Pace Calculator: Pace, Speed & Splits
Min/km and min/mile pace, speed, and kilometre splits for any distance from 400 m to ultra distances.
RecoveryRace Time Predictor: Riegel Formula
The Riegel formula (T₂ = T₁ × (D₂/D₁)^1.06): predictions for 5k, 10k, half marathon and marathon from any recent result.
RecoveryHYROX Calculator: Pacing, Station Benchmarks, Roxzone and Weights
Pacing splits for any target finish, station times ranked against 395,452 results, roxzone from your own splits, and official division weights.
RecoveryCaffeine Half-Life Calculator
Chart how a dose decays over 24 hours (C(t) = dose × 0.5^(t/t½)) and when it drops below your chosen sleep threshold.
RecoveryPhenotypic Age Calculator: Biological Age from Blood Tests
Free Phenotypic Age (PhenoAge) calculator using the peer-reviewed Levine 2018 model: nine blood biomarkers plus age…
RecoveryHeart Age Calculator: Your Cardiovascular Age from PREVENT
Free heart age calculator built on the AHA PREVENT equations (2024): enter blood pressure and cholesterol to see your heart age an…
RecoveryCGM Metrics Calculator: GMI, Time in Range & Variability
GMI, time in range and glucose variability (%CV) from your own readings, using the international consensus definitions.
RecoveryHealthy Lifestyle & Life Expectancy: The Evidence
How five healthy habits related to life expectancy at 50 in the Li 2018 study: 12 to 14 extra years on average with all five.
RecoveryMetabolic Fitness Index: Open, Transparent Score
HbA1c, fasting glucose and insulin, triglyceride:HDL ratio, waist-to-height and resting heart rate as one transparent 0 to 100 score.
RecoveryPace of Aging Index: Open Lifestyle-Trajectory Score
A transparent 0 to 100 lifestyle-trajectory score from fitness, activity, sleep and habits.
RecoveryRecovery Readiness Index: Open, Self-Relative Score
A daily 0 to 100 score comparing today's HRV, resting heart rate and sleep to your own baseline.
RecoveryVO2max Calculator: Cooper, Rockport & Heart-Rate Methods
The Cooper 12-minute run, the Rockport 1-mile walk and the Uth heart-rate ratio method.
RecoveryFitness Age Calculator: How Old Is Your Body, Really?
Free Fitness Age calculator built on the HUNT study (Nes 2011).
RecoveryCalories Burned by Heart Rate Calculator
Free calculator for calories burned from average heart rate, using the Keytel 2005 equations (sex, age and weight) for steady-state aerobic exercise.
Recovery