Running calculators
Daniels/Gilbert math, straight from the open-source engine. No sign-up, everything runs in your browser.
Pace calculator
Distance and time in — pace, speed and even splits out. min/km or min/mile.
Training pace calculator
Turn one real race result into your easy, threshold, interval and race paces.
Race time predictor
What your 5K says about your marathon — equivalent performances across distances.
Easy pace checker
Are your easy runs too fast? A race result in, an honest verdict out.
Heat pace calculator
How much to slow down when it’s hot — from temperature, humidity and dew point.
