Concept2’s formulas
Watts = 2.80 ÷ pace³ (pace = seconds per metre = split ÷ 500)
Monitor calories/hour = 4 × 0.8604 × watts + 300 · your calories/hour = monitor − 300 + 1.714 × weight (lb)
Weight factor Wf = (weight lb ÷ 270)0.222 · adjusted time = Wf × actual time
Monitor calories/hour = 4 × 0.8604 × watts + 300 · your calories/hour = monitor − 300 + 1.714 × weight (lb)
Weight factor Wf = (weight lb ÷ 270)0.222 · adjusted time = Wf × actual time
The watts formula is the one in Concept2’s watts calculator. The monitor’s calories-from-watts formula is the widely documented one above (Concept2 does not publish it on its calculator page), and its figure assumes a 175 lb (79 kg) rower; Concept2’s calorie calculator gives the correction for your weight. The weight adjustment lets rowers of different weights compare times.
Split to watts chart
| Split /500m | Watts | 2,000 m | 5,000 m |
|---|---|---|---|
| 1:35 | 408 W | 6:20 | 15:50 |
| 1:40 | 350 W | 6:40 | 16:40 |
| 1:45 | 302 W | 7:00 | 17:30 |
| 1:50 | 263 W | 7:20 | 18:20 |
| 1:55 | 230 W | 7:40 | 19:10 |
| 2:00 | 203 W | 8:00 | 20:00 |
| 2:05 | 179 W | 8:20 | 20:50 |
| 2:10 | 159 W | 8:40 | 21:40 |
| 2:15 | 142 W | 9:00 | 22:30 |
| 2:20 | 128 W | 9:20 | 23:20 |
| 2:25 | 115 W | 9:40 | 24:10 |
| 2:30 | 104 W | 10:00 | 25:00 |
| 2:40 | 85 W | 10:40 | 26:40 |
Why a few seconds cost so much
Power rises with the cube of boat speed. Going from a 2:00 split to 1:50 — about 9% faster — needs about 30% more power (203 W to 263 W). That is why the last seconds off a 2k are the hardest.
Last reviewed: 2026-10-04 · Disclaimer