Methodology and Sources
Running Toolkit calculators are built for planning and comparison. Some outputs are exact arithmetic, while physiology outputs are estimates from common field formulas.
Last updated: May 30, 2026
Exact Calculations
Pace, speed, distance conversion, and split calculations use deterministic arithmetic. They are only as accurate as the distance and time values entered.
Estimate-Based Calculations
Running calories use 2024 Compendium of Physical Activities running MET values, body weight in kilograms, duration in hours, and a heuristic elevation adjustment.
Race predictions use a Riegel-style endurance formula with exponent 1.06.
VO2 max uses the Cooper 12-minute run field-test estimate.
Heart-rate zones use either a known max heart rate or the Tanaka-style estimate 208 - 0.7 x age.
Limitations
These calculators do not replace lab testing, medical advice, a coach, or a sports dietitian. Real-world results vary with running economy, body composition, route measurement, surface, wind, heat, altitude, fatigue, fueling, and device accuracy.