What formula does Concept2 use for calories?

Concept2 derives power in watts from your pace, then converts it with the relation Cal/hour = (4 × watts) + 300. The +300 represents the energy you would burn at rest, so even a very light row registers some calories per hour.

How is power calculated from my split?

The PM monitor uses power = 2.80 / pace³, where pace is the time in seconds to cover one metre (your 500m split time divided by 500). A faster split means a smaller pace value and a much larger power figure because of the cube relationship.

Why are erg calories higher than my heart-rate monitor's?

The Concept2 figure includes the resting energy you would burn anyway (the +300 term), so it tends to read higher than devices that estimate only the calories above rest. Neither is wrong; they measure slightly different things.

Does bodyweight change the erg calorie reading?

No. The Concept2 calorie display is based purely on mechanical power and is independent of bodyweight, so two rowers holding the same split see the same calories. Real metabolic cost varies with weight, but the machine standardises on power.

Why does halving my split more than double the calories?

Because power scales with the cube of speed. A small improvement in pace produces a large jump in watts, so calories rise steeply as you row faster. This is why short, fast pieces feel so much harder than the split difference suggests.

Rowing Ergometer Calorie Calculator

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The same maths your monitor uses

The Concept2 rowing monitor does not guess at calories — it computes them from the mechanical power you produce. This calculator reproduces that exact chain: it turns your 500m split into watts, then watts into calories per hour, then scales by your session length. The result matches what the PM5 display would show for the same effort.

How it works

First, convert the 500m split into pace (seconds per metre) and then into power:

pace_s_per_m = split_seconds / 500
watts        = 2.80 / pace_s_per_m^3

Then apply the Concept2 calorie relation and scale by duration:

cal_per_hour = (4 * watts) + 300
calories     = cal_per_hour * (minutes / 60)

The cubic power law is why a faster split costs disproportionately more energy, and the +300 term is the resting metabolic baseline built into the official display.

Example and tips

A 2:00 / 500m split is 120 seconds, so pace is 120 / 500 = 0.24 s/m and power is 2.80 / 0.24³ ≈ 202 W. That gives (4 × 202) + 300 = 1,108 Cal/hour, so a 30-minute row burns about 1108 × 0.5 = 554 calories. To raise calorie burn, lower your split rather than just rowing longer — because of the cube law a 10-second-faster split adds far more watts than equivalent extra time would.