MilePaceLab

Methodology

Every MilePaceLab result comes from one shared formula library that works in meters and seconds. Values are rounded only when shown, and every chart is generated from the same code as the calculators.

Constants

  • 1 mile = 1,609.344 meters (the international mile, exact).
  • 5K = 5,000 m, 10K = 10,000 m, half marathon = 21,097.5 m, marathon = 42,195 m.
  • 1 kilometer = 1,000 meters.

Formulas

  • Pace per mile (seconds) = time in seconds ÷ distance in miles.
  • Speed in mph = 3,600 ÷ pace per mile in seconds, which equals 60 ÷ pace in minutes.
  • Pace per kilometer = pace per mile ÷ 1.609344.
  • Speed in km/h = mph × 1.609344.
  • Finish time = pace per mile × distance in miles.

Rounding and display

Calculations keep full precision. Pace and finish times are rounded to the nearest whole second when displayed, so 7:59.6 shows as 8:00. Speeds show two decimals in tables. Pace is always shown as minutes and seconds, never as decimal minutes.

Limits

The calculators accept speeds from 1 to 30 mph and paces from 2:00 to 60:00 per mile. Outside that range they show a message instead of a result.

Testing

Automated tests compare every published chart row and worked example with independent calculations, check text parsing and rounding edge cases, and confirm that converting pace to speed and back returns the starting value. A page is not published if a test fails.

Sources

  • Daniels, J. and Gilbert, J. (1979). Oxygen Power: Performance Tables for Distance Runners, and Daniels, J. (2014), Daniels’ Running Formula, 3rd edition. Used on the training pace calculator.
  • Riegel, P.S. (1981). Athletic records and human endurance. American Scientist, 69(3), 285–290, and Vickers, A.J. and Vertosick, E.A. (2016), BMC Sports Science, Medicine and Rehabilitation. Used on the race time predictor.
  • Ely, M.R. and colleagues (2007), Montain, S.J. and colleagues (2007), and Gasparetto, T. and Nesseler, C. (2020), on heat and marathon performance. Used on the heat guide.
  • Jones, A.M. and Doust, J.H. (1996). A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of Sports Sciences, 14(4), 321–327. Used on the MPH to min/mile page.

New sources are listed here when a page starts using them.

Editorial standards and AI assistance

  • Calculations come from one tested formula library. A page is not published if a test fails.
  • Facts, studies and statistics name their source. Where a stable link exists, it is given. Where it does not, the citation says so.
  • Pages state what a source covers and what it does not, including the limits of a single study.
  • AI tools, including Claude, are used for research, drafting and quality checks. The author reviews the output and is responsible for what is published.
  • Pages are not written to match a keyword list. Each page exists to answer a specific question.
  • The site gives general information. It is not medical advice and does not replace a coach or clinician. See the disclaimer.

Corrections and updates

If you find an error, tell us. Confirmed errors are fixed and the change is logged below. The date on a page changes only when its content changes.

Change log

  • 2026-11-02: first release with 13 calculators and converters, 6 guides and the pages that describe how the site works.