Runners Lab is the publisher of the free running calculators at runnerslab.app. There is no login, no account, and no training diary. The math runs in your browser. It is deterministic: the same inputs always produce the same outputs.
Runners Lab is made by Yanchi.
The site is English-only. Calculators cover pace, races, training volume, energy and fueling, environmental conditions, fun tools, heart rate, performance, track, treadmill, cadence, hills, and elevation. Model-based tools cite the formulas they use. Exact tools do arithmetic, not prediction.
Nothing here is a coaching service, a wearable, or an AI product. If you want the numbers, open a tool. If you want the formulas, read the methodology.
Questions: use the contact form or email yanchi@yanchi.space.