About GrowLytics Run
Free, transparent running calculators built on published sports science.
What this site is
GrowLytics Run is a collection of free running calculators and goal pace charts. It covers the questions runners ask most often — how fast did I run, what could I race, how fast should I train, and how should I pace race day — and answers them with clear numbers and plain-language explanations.
The site is part of GrowLytics, an independent SEO and digital marketing platform that also publishes 60+ free SEO tools for website owners. We built these calculators because many running calculators online either hide their methods, bury the result under pop-ups, or ask for an email address before showing you a number.
How the calculators work
Every calculator uses a published, well-established model, and each page explains the formula with worked examples and sources:
- Pace, speed, splits and conversions — exact arithmetic.
- Race predictions — Peter Riegel’s endurance formula (1977/1981) and the Daniels & Gilbert VDOT equations (1979).
- Heart rate zones — the Fox, Tanaka and Gulati max heart rate equations and the Karvonen heart rate reserve method.
- Treadmill incline — the energy cost of running equation from Minetti et al. (2002) and the 1 % grade finding of Jones & Doust (1996).
- Calories — the American College of Sports Medicine (ACSM) metabolic equations.
- Track lanes — standard World Athletics track geometry.
Calculations run in your browser, so results appear instantly and the numbers you type are not sent to our server.
Accuracy and limits
Predictions describe averages. Your own results depend on training, experience, course, weather and many other factors, so treat every estimate as a starting point and adjust by feel. Nothing on this site is medical advice — please read our health disclaimer.
Corrections and suggestions
If you spot an error or would like a calculator we don’t have yet, we’d love to hear from you. Visit our contact page.