Erg Calculator

Concept2 measures pace as the time to row 500 m. It is like time per mile in running, so a smaller number is faster^[5].

Concept2's Pace Calculator uses these three: distance = (time ÷ split) × 500, split = 500 × (time ÷ distance), and time = split × (distance ÷ 500)^[2]. Its own example is 2,000 m at a 1:50 split, which gives 7:20.

Worked example. A 7:00 2k is 420 seconds. Divide by 2,000, multiply by 500, and you get 105 seconds, a 1:45.0 split.

That split is about 302.3 W. The calculator then shows your time at that split for common distances, so you can see what the same pace would mean over 5,000 m or 10,000 m.

Concept2's Watts Calculator gives watts = 2.80 ÷ pace³ and pace = the cube root of (2.80 ÷ watts), where pace is time in seconds over distance in metres^[1].

Its worked example is a 2:05 split. That is 125 seconds over 500 m, a pace of 0.25, and 2.80 ÷ 0.015625 = 179.2 W. The calculator reproduces that figure.

Watts to split. At 200 W, divide 2.80 by 200, take the cube root, and multiply by 500. That is a 2:00.5 split.

Watts follow pace. In Concept2's formula the split fixes the watts, so any two rowers on the same average split get the same watts, whatever their size.

Why a few seconds cost so much. Pace is cubed, so power climbs faster than speed. Going from 2:00 to 1:55 takes you from 202.5 W to 230.1 W, about 27.6 W more for five seconds.

Drag factor. Concept2 says the Performance Monitor already allows for the damper setting and recalibrates every stroke for the damper and ambient conditions^[3]. The formula has no damper input.

Times are rounded to a tenth of a second and watts to the nearest whole number. The calculator above keeps more decimals, so a result there can differ from a chart row by a tenth of a second.

The factor is Wf = (body weight in pounds ÷ 270) ^ 0.222. Corrected time is Wf × your actual time, and corrected distance is your actual distance ÷ Wf^[3].

Worked example. A 70 kg rower is 154.3 lb, so Wf = 0.883. A 7:00 2k becomes 6:11.0, and the same effort adjusted for distance is 2,264 m.

I found no worked example for this formula on Concept2's page, so the test for it is a hand calculation. The calculator gives 6:11.0 for the same inputs.

What it means. Concept2 explains it as a way to estimate potential speed in an eight, because a heavier rower sits deeper in the water and the erg does not penalise that^[3]. Concept2 says the formula applies to women as well as men^[3]. The 270 lb reference is its chosen standard rower, not a target weight.

What it does not do. Your adjusted score cannot be entered in the Concept2 Online Ranking, which takes raw times and distances only^[3]. For a rough on-water estimate, the Erg to Boat Speed Calculator applies the same adjustment to a 2k.

Below 270 lb (122.5 kg) the factor is under 1, so almost every adjusted time is faster than the raw one. That is how the formula works, not a sign that you rowed better.

The five names are Concept2 UK's training bands: utilisation 2 (UT2), utilisation 1 (UT1), anaerobic threshold (AT), oxygen transport (TR) and anaerobic (AN)^[4]. Its Table 3.1 sets each by heart rate as a percentage of maximum: 55 to 70, 70 to 80, 80 to 85, 85 to 95 and 95 to 100.

Its Table 5.8, the 2,000 m Training Pace Guide, gives a pace for each band from your current 2k time^[4]. For a 7:00 2k the paces are UT2 2:01.0 or slower, UT1 1:56.0 to 2:01.0, AT 1:51.0 to 1:56.0, TR 1:45.0 to 1:51.0, AN 1:42.0 or faster.

How I read the table. Each printed figure is the fast end of its band, and a band runs back to the figure on its left. The TR figure equals your 2k average split in every row I used.

The table prints TR and AN with signs that point the opposite way to the guide's own text. I followed the text. The guide sets no band between TR and AN.

Rows I left out. The 5:40 and 5:44 rows show UT1 no slower than AT, and the AT column sits at 1:35.0 from 5:44 to 6:00. They look misprinted, so the supported range starts at 6:04.

Where the guide disagrees with itself. Its text on page 3.06 says the percentages are of heart rate range added to resting heart rate. Tables 3.1 and 3.2 use percent of maximum, so I show those.

Table 3.1 also gives different stroke rates from Table 5.8: 18 to 20, 20 to 24, 24 to 28, 28 to 32 and 32 or more. The calculator shows Table 5.8's.

How current it is. This is version 2 of the guide, and the PDF has file dates of 2003 and 2007. I found no newer edition, and Concept2's current Training Guide PDF has no pace table by band^[10]. Treat the bands as an older guide's advice, not current Concept2 guidance.

In-between times. The table has a row every 4 seconds. If your 2k falls between two rows, I draw a straight line between them and the tool tells you so.

Why other sites show different bands. One Concept2 forum poster says the guide never defines bands in watts, and that the interactive plan's spreadsheets use percentages of 2k power instead, such as UT2 at 45 to 60 percent^[7]. I could not check the spreadsheets, so treat that as one poster's claim.

That is why this page uses the printed table. The Rowing FTP Calculator uses the percentage convention, so its bands will not match these. Concept2's own marathon plan sets its bands against 5k pace instead, which is another reason bands differ^[6].

Concept2's 2k plan suggests holding a constant pace, or using negative splits, which means starting one or two seconds slower than target and finishing faster^[5]. It warns that going out too hard feels easy at the start.

To plan every 500 m of a race, use the Rowing Race Pace Calculator. To turn a 2k into a running time, use the Erg to Run Equivalence Calculator.

For a longer-piece power estimate, the Rowing FTP Calculator and the Rowing Critical Power Calculator work from your own results.

• The old zone multipliers. The old page set its zones as fixed multiples of the test pace (1.20, 1.10, 1.00, 0.92 and 0.85) and ignored how long the test was. I found no source for them.
• Experience, goal and age inputs. They adjusted the old multipliers or fed nothing at all. The calculator no longer asks for them.
• Level labels, weekly splits and durations. The old Elite, Advanced and Intermediate labels from watts per kilogram, the weekly percentage splits and the zone durations had no source.
• A wrong worked example. The old page said a 2:07.5 split gave 185 W. Concept2's formula gives 168.9 W^[1].
• Calories. I left them out on purpose. Concept2's Calorie Calculator adjusts the monitor's figure for body weight^[8], and that needs its own tool.
• 2k prediction from a 5k. The Ultimate Erg Calculator site credits the rule to Paul Smith and says Paul's Law is not a predictor, but a way to see whether speed or endurance is your limit^[9]. I found no source that supports using it to predict a time.
• BikeErg. Concept2's pace calculator has a separate setting for the BikeErg^[2]. I could not confirm its split rule on a Concept2 page, so this tool covers the RowErg and SkiErg only.
• Rankings and standards. I did not add a rating scale for good or poor times, because I have no first-party standard to base one on. The Erg to Boat Speed Calculator gives a weight-adjusted view of a 2k.