About PaceKeeper

PaceKeeper exists because most runners train too fast on easy days and race too fast on day one.

The two most expensive pacing errors in running are symmetrical: hammering easy runs (which adds fatigue without the stimulus that speed provides) and going out 30 seconds per mile too fast in a race (which converts a PR attempt into a survival shuffle). Both are fixable with arithmetic done in advance.

Our calculators implement the published math — Riegel's endurance equation for race predictions, Daniels-style zone boundaries for training paces, negative-split split tables — and show their assumptions so you can see exactly when they apply and when they flatter you.

We are runners and educators, not coaches selling plans. Every tool is free, runs in your browser, and never asks for an email.

What makes PaceKeeper different

• Your numbers never leave your browser. Every calculator on PaceKeeper runs entirely on your device. We never see, store, or transmit the figures you enter — there are no accounts and no server-side processing of your inputs.
• Published methodology. Each calculator page explains the exact formula it uses and the assumptions behind it, so you can check our work or reproduce it in a spreadsheet.
• Free, forever, without a paywall. PaceKeeper is supported by advertising. There is no premium tier, no email gate, and no upsell.

Independence

PaceKeeper is an independent educational project. We are not affiliated with, endorsed by, or acting on behalf of any government agency, lender, insurer, or the organizations whose formulas and public data we reference (such as published exercise-physiology research (Riegel, Daniels) ). All trademarks and referenced standards belong to their respective owners.

Questions, corrections, or suggestions are genuinely welcome — get in touch.