Useful numbers.
Honest uncertainty.
Every calculator shows its assumptions, gives you a range where a range is more truthful, and tells you what the number cannot know.
RUNNING · INTENSITY
Zone 2 + all heart-rate zones
Use heart-rate reserve by default, see all five zones, and treat age as the fallback when no credible exercise data exists.
Open tool →RUNNING · RACE PLANNINGMarathon time predictor
Turn a recent 5K, 10K or half marathon into a theoretical ceiling and a more conservative planning estimate.
Open tool →HYROX · PACINGHYROX ↔ 5K pace converter
Translate fresh-road speed into an honest compromised-running range for Singles or Doubles.
Open tool →HYROX · FIRST RACEHYROX readiness check
Assess preparation coverage across running, consistency, station familiarity and time remaining.
Open tool →