CrossFit Calorie Converter

Why boxes convert calories at all

A WOD written for a rower does not stop being fair just because your box only has an air bike free that day. Coaches convert the calorie count so the machine swap changes as little as possible about how hard the piece actually is, rather than telling everyone to hit the same number regardless of what that number costs on their machine. Skip the conversion and the workout quietly stops being the workout that was programmed: whoever lands on the more generous machine gets an easier day, and nobody chose that on purpose.

None of this is hidden physics. It is a working convention that coaches and affiliate programmers have converged on by comparing machines side by side, and it is honest to say so plainly rather than dress a rule of thumb up as a formula. That is also why every figure below is a range and not a single number: pretending to a precision the convention does not have would be less accurate, not more.

Where these ranges come from

Three figures drive every conversion on this page, each pulled from published coaching guidance rather than invented for this tool:

The air bike range comes from box-conversion guidance that puts the Assault Bike at roughly 70% of rower calories for matched effort, with wider coaching material citing figures up to around 75 to 80% depending on the exact model; independent testing on the Rogue Echo Bike has found 10 rower calories landing close to 7 Echo Bike calories, near the bottom of that band. Assault and Echo bikes are calibrated differently from one another, which is exactly why a range fits better than one shared number.

The ski erg range is a little different in kind. Concept2's SkiErg runs the identical calorie algorithm as its rower, the same watts-to-calories formula on the same PM5 monitor, so in principle a given power output should read the same on both. In practice, most athletes are measurably less efficient moving a ski erg than a rower, since it asks for a less-drilled movement pattern, so published box guidance scales ski targets down to 80 to 100% of the row number for a fair swap; only an athlete who can hold a true rowing-equivalent split pace on the ski erg should use the full 100%.

Bike-to-ski conversions on this page run through the rower figure as a benchmark, since no box guidance publishes a direct bike-to-ski factor. That means a bike-to-ski (or ski-to-bike) result carries two stacked ranges of uncertainty rather than one, and the matrix below is wider for that pair on purpose. It is not a bug in the arithmetic; it is what happens honestly when you chain two separate conventions.

Why each machine reads a different number for the same effort

Concept2's rower is the anchor because its calorie figure is built from a published formula: calories per hour equal roughly four times the watts produced, scaled by an efficiency constant, plus a baseline of around 300 kcal per hour credited even at zero power. That baseline is why a rower reading never truly touches zero calories over time and why the whole conversion problem exists in the first place: it is a formula tuned to one reference monitor, not a universal measure of energy actually burned.

Air bikes work the whole body, arms driving the fan as much as the legs, which by feel is at least as hard as rowing at a matched pace. What the monitor credits for that effort is a separate question from what the effort costs, and most air bike monitors simply do not award as many calories per unit of perceived exertion as a Concept2 rower does for the same subjective grind. That mismatch, not a difference in how hard the athlete is working, is the entire reason the bike figure sits below the row figure in the conversion.

The ski erg leans on the upper body and core in a way rowing and biking do not, pulling through the lats, triceps and trunk with the legs playing a smaller supporting role. Because so much of a typical gym-goer's training happens on the lower body, most athletes simply have not built the specific efficiency on a ski erg that they have on a rower, and a less efficient stroke needs more real work to post the same calorie count. That gap, not the machine's programming, is what the ski erg discount is quietly correcting for.

Pace versus total calories

Coaches sometimes talk in calories per minute rather than a flat total, and the commonly cited training benchmarks put a well-trained athlete's hard rowing effort at somewhere around 15 to 20 calories a minute, against roughly 12 to 15 a minute for the same athlete pushing hard on an air bike. Treat those as rough, widely repeated training reference points rather than a target to hit, since fitness, technique and even the specific machine model move the true number a good deal for any one person.

The honest bit about who this favours

Calorie pace scales with power output, and power output scales with body size, so a heavier or taller athlete generating more watts per stroke will rack up a fixed calorie count faster than a smaller athlete working just as hard. That is not a fitness gap or a mark against the smaller athlete's effort; it is a known feature of how these monitors are built, and it is an active discussion at plenty of boxes when calorie-based pieces are programmed for mixed classes. Some coaches respond by scaling calorie targets by bodyweight or by switching to a fixed work time instead of a fixed calorie count for exactly this reason. None of that changes the ranges on this page, but it is worth knowing the number in front of you was never designed to be size-neutral.

Your box's standard wins

If your gym already has its own printed conversion chart on the wall, use that over the range this page gives. Programming a fair swap matters more as a fixed, agreed convention within one gym than as a match to any particular published range, this one included: an affiliate that has always scaled bike calories at a flat 75% will keep its history consistent by staying at 75%, even on the days that figure sits at the edge of what wider coaching material cites. This page's ranges are a solid, sourced starting point for a box that has not settled on its own number yet, not a replacement for one that already has.

Questions people ask

These conversions describe a coaching convention drawn from published box guidance, not a measured physical law. Individual fitness, technique, machine model and calibration all move the true figure for any one person or gym; treat every range here as a fair starting point, not a certified equivalence.