Free running calculators
Pace, race times, training zones, splits, heart rate, fueling. No signup, no ads, no tracking. Built by Empace — your AI running coach.
Pace Converter
min/km ↔ min/mile ↔ km/h ↔ mph in real time.
Race Time Predictor
Predict your 5K, 10K, half, and marathon from a recent race. Riegel + VDOT.
Training Pace Zones
Easy, marathon, threshold, interval, repetition — Jack Daniels VDOT.
Marathon Split Planner
5K splits for an even, negative, or positive split goal time.
HR Zone Calculator
Five heart rate zones using %MaxHR or Karvonen reserve.
Race Fueling Calculator
Carbs, gels, fluid, and sodium for your race-day plan.
★★★★★
“Surprised how nice it was to chat with it! Got a few good suggestions for how to train with my injury.”
