Contact Us
Have questions, suggestions, or found a bug? We'd love to hear from you.
Send us an email at
contact@calcpace.appAbout Calcpace: Built by Runners, for Runners
Calcpace is a free running performance platform built on the belief that every runner — from first-time 5K finishers to seasoned marathoners — deserves access to the same scientific tools used by coaches and sports scientists. Most pace calculators online apply a single linear formula and call it done. Calcpace uses the models that coaches actually rely on — the Riegel and Cameron formulas for race prediction, the Daniels and Gilbert method for VO2max, and WMA 2023 standards for Age Grading — and explains what each result means.
If you have a question about how a specific formula works, found a bug, or want to suggest a feature, this is the right place. We are a small team and read every message personally. Feedback from coaches, exercise physiologists, and athletes who want to challenge or improve the methodology is especially welcome. The math behind Calcpace is fully open source — the same calculations are available as a Ruby gem on RubyGems.org.
The public calculators work entirely in your browser and store nothing on our servers. If you create a free account to log activities, your data is private by default and is never sold to third parties. The logged-in area is 100% ad-free and tracker-free. Ads appear only on public pages (calculators, guides, race calendar) to cover infrastructure costs.
How does this work?
Is Calcpace free to use?
Yes — all public calculators, guides, and the race calendar are completely free with no account required. Creating a free account unlocks activity logging and tracking. The logged-in experience is 100% ad-free and tracker-free.
Where is the source code?
The mathematical core of Calcpace is open source. The calcpace Ruby gem is published on RubyGems.org and includes all the formulas — Riegel, Cameron, Daniels and Gilbert VO2max, and WMA Age Grading — with full test coverage and documentation.
How do I report a bug?
Send an email to contact@calcpace.app with a description of what you expected, what happened instead, and (if relevant) the inputs you used. Screenshots are helpful. We respond to all reports, usually within a few business days.