Convert between time, distance, pace, watts and calories on any machine — and find the effort on one machine that matches an effort on another. Built because "20 calories" and "500 metres" are not the same workout for everybody, and almost nothing online will tell you that honestly.
Air bikes and curved treadmills have no published formula, and no two models agree. Rather than invent numbers, this tool starts from rough estimates and lets you replace them with your own. Do one all-out minute on each machine you use, enter the calories, and every conversion below becomes yours instead of a guess. Saved in this browser only.
Every conversion here runs through watts, because power is the only unit that means the same thing on every machine. How reliably a machine's other numbers map to watts is what separates the three tiers below.
Concept2 RowErg and SkiErg. Concept2 publishes the pace-to-watts formula and the calorie offset, so these conversions are arithmetic, not estimation.
Concept2 BikeErg and running. Watts and calories are solid; the pace and distance relationship relies on a constant Concept2 doesn't publish, so it's calibrated rather than derived.
Assault AirBike, Rogue Echo Bike, Assault Runner. No manufacturer formula exists and the machines disagree with each other. Calibrate these or treat them as a ballpark.
Concept2 publishes this directly. Pace is measured in seconds per metre — so a 1:52 split over 500 m is 112 ÷ 500 = 0.224 s/m.
The cube is the reason erg pace feels so unforgiving. Going 10% faster costs you about 37% more power, which is why the last 500 m of a 2k hurts so far out of proportion to the time it saves.
The monitor converts mechanical work to calories at an assumed 25% efficiency, then adds a flat resting-metabolism term. One watt sustained for an hour is 0.8604 kcal of mechanical work; divide by 25% and add the resting rate:
That +300 is the whole story of calorie workouts. Because it's added regardless of how hard you're going, calories accumulate even at zero power — so a calorie target rewards anyone who can simply keep the handle moving, and rewards a heavier athlete over a lighter one at the same relative effort. A metre is a metre. A calorie is not.
Concept2 confirms the monitor is calibrated for a 175 lb person and publishes the correction for everyone else:
Concept2 does not publish the BikeErg's pace constant, and Assault and Rogue publish nothing at all about how their consoles compute calories. Any site giving you a precise Echo-Bike-to-rower conversion is guessing and not telling you. The defaults here are honest estimates; the calibration panel is how you make them right. One hard minute per machine and the numbers become yours.
Running is different again: running calories depend on your bodyweight in a way erg calories don't, because you're carrying yourself. The running estimates here use roughly 1 kcal per kilogram per kilometre, which is a well-established approximation and still only an approximation.