Home / Running
Running Calculators
Free running calculators for pace, race-time prediction, VDOT and training paces, VO₂max, heart-rate zones, hills, and age grading — built on the formulas coaches actually use, and free to use in your browser.
Pace Calculator
Solve for pace, time, or distance — and split it out.
OpenPace Converter
Convert between min/km, min/mile, km/h, and mph instantly.
OpenRace Predictor
Predict your 5K, 10K, half, or marathon from a recent race.
OpenVDOT & Paces
Get your VDOT and Daniels easy/threshold/interval paces.
OpenVO₂max
Estimate VO₂max from a race, a 12-min test, or 1.5 miles.
OpenYasso 800s
Turn 800 m repeats into a marathon estimate, or back.
OpenHR Zones
Five training zones from max HR, HR reserve, or threshold.
OpenRun/Walk
Blend run and walk intervals into an average pace and finish time.
OpenTreadmill
Treadmill speed and incline → outdoor pace and calories.
OpenGrade-Adjusted Pace
Convert hill pace to flat-equivalent effort, and back.
OpenAge Grading
Score your race against the world standard for your age and sex.
OpenQuestions
Which running calculator should I use to set my training paces?
Start with the VDOT calculator: enter a recent race result and it returns your easy, marathon, threshold, interval, and repetition paces from Jack Daniels’ tables. Use the pace calculator to turn any target time into per-km and per-mile splits.
How do I predict my marathon time from a shorter race?
Use the race-time predictor, which applies Pete Riegel’s endurance formula to project a finish at any distance from a recent result. Predictions from very short races tend to be optimistic for the marathon, where endurance and fuelling dominate.
Are these running calculators free?
Yes. Every tool is free, needs no account, and is free to use in your browser.