Running calculators

Pace, race prediction, VDOT, age grading, treadmill conversion, pace charts and pace bands. Free, no sign-up.

• Pace calculatorSolve for pace, time or distance, and see every split.
• Pace chartEvery pace from 3:00 to 8:00 /km and 5:00 to 13:00 /mile, as a table to read.
• Race time predictorWhat your time is worth at every other distance. Three models, side by side.
• VDOT calculatorYour Daniels & Gilbert VDOT, and the race times it implies.
• Age grade calculatorScore a time against the world standard for your age and sex (WMA 2020).
• Treadmill pace converterBelt speed to outdoor pace, plus what an incline costs you.
• Pace band generatorAn even or negative-split plan you can print and carry.

Why you can trust the numbers

Most running calculators never say which model they use, so when two disagree you can't tell which one is wrong. Every tool here names its model, shows the formula and cites the source.

Where a model has a known weakness the page says so next to the number, not in small print at the bottom. Riegel over-predicts a marathon off a 5K. Age-grade factors are a fitted standard, not a measurement.

The arithmetic is a port of the code the apps run, and a build check re-runs the apps' own test suite against the browser version. They can't drift apart without CI failing.