Erg Calculator

What is an erg?

'Erg' is short for ergometer, a machine that measures work. In rowing it means the indoor rowing machine – most often a Concept2 RowErg, which clubs and gyms around the world use for training and for official test pieces. The monitor shows pace as time per 500 m (the split) and can also show watts and calories.

Split to watts formula

• Watts = 2.80 ÷ (split ÷ 500)³
• Split = 500 × (2.80 ÷ watts)^(1/3)

Because pace is cubed, power rises steeply as the split gets faster. Going from 2:00 to 1:52 – eight seconds – takes power from 202 W to 249 W, an increase of about 23%. That is why the last few seconds off a 2k feel so hard.

Predicting 2k and 5k times

Time at a constant split is split × distance ÷ 500. A 2:00 split gives 8:00.0 for 2,000 m and 20:00.0 for 5,000 m. Real race times are rarely that even: most rowers can hold a faster split over 2k than over 5k, so use a recent test at the same distance when you can.

Worked example

A club rower holds a 1:52.0 split. Pace = 112 ÷ 500 = 0.224 s/m; 0.224³ = 0.011239; 2.80 ÷ 0.011239 = 249 W. At that pace 2,000 m takes 112 × 4 = 448 s, or 7:28.0. Weighing 70 kg, she produces 249 ÷ 70 = 3.56 W/kg.

What is a good erg split?

It depends on age, sex, weight and experience. As a rough guide, many newer rowers start around 2:10–2:30 for steady work, trained club rowers often race 2k between about 1:40 and 1:55, and international heavyweight men race well under 1:30. Concept2's online logbook lets you compare against rowers of the same age and weight, which is far more useful than a single benchmark.

Stroke rate, drag factor and accuracy

Stroke rate (strokes per minute) changes how you produce power, not how watts are calculated. Drag factor changes how heavy the flywheel feels, but the monitor measures the flywheel's actual slowing, so split and watts stay comparable across settings. SkiErg and BikeErg use their own pace units, so convert their figures with their own monitor rather than the rowing split table.

Split needed for a target 2k time

Divide the goal time by four to get the average split. Most coaches suggest starting slightly faster for the first 100–200 m, settling into goal pace and finishing hard, rather than going out far too fast.

Sources

1. Concept2 – Pace-to-Watts calculator (watts = 2.80/pace³) — concept2.com/training/watts-calculator