PacerRunning

PacerRunning is a free online hub of running calculators designed to help runners turn a recent race result or goal time into practical predictions and pacing guidance. Its tools draw on widely used methods, including Daniels’ VDOT, Riegel and Cameron race prediction models, and Karvonen and ACSM training zones. Enter one recent result to generate aligned race-time estimates, personalized training paces and target-race splits, without creating an account.

Runners can explore predicted finishes and model ranges, easy-to-interval training zones, even or negative-split plans, and detailed mile or kilometer pace tables. The site also offers calculators for race pace, pace conversion, cadence, run-walk strategies, track laps, treadmill incline, and adjustments for altitude, hills and heat. A separate training-plan calculator creates a dated, week-by-week schedule that can be exported to a calendar or printed, including as a PDF.

Results identify their primary source, US units are the default with a metric toggle, and the site states that user entries are not stored