Useful, free web tools
A small, growing collection of tools with no sign-up and no clutter.
Ryutility builds calculators for runners who train by numbers — VDOT training zones, heart-rate zones, race pace, race prediction, split strategy, and treadmill conversion, all using established, published methods rather than guesswork. Every calculator is paired with a guide that explains the reasoning behind the numbers, not just the numbers themselves.
Training Zone Calculator
Calculate your personalized training zones from a recent race time using Daniels' VDOT method.
RunningRunning Pace Calculator
Calculate your running pace, finish time, or distance — enter any two and get the third, in km and miles.
RunningRace Time Predictor
Predict your finish time for 5K, 10K, half, and full marathon from one recent race result using the Riegel formula.
FitnessHeart Rate Zone Calculator
Calculate your five heart rate training zones with the Karvonen method, from your max and resting heart rate or your age.
RunningSplits Calculator
Build a printable split table for any race — even or negative splits per km or mile for 5K to marathon.
RunningTreadmill Pace Converter
Convert treadmill speed (mph or km/h) to running pace, and see the equivalent outdoor pace for any incline setting.