This erg calculator converts between the three languages of the rowing ergometer — split (per 500 m), watts, and total time over a distance — using the Concept2 power law: watts = 2.8 × (500 ÷ split in seconds)³.

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Splits, Watts, and the Tyranny of the Cube

Erg rowing speaks in splits — the time per 500 m — because races are watched in pace, but it thinks in watts, because the physics of moving a hull (or spinning a flywheel) prices speed through a cube law: drag force grows with velocity squared, so the POWER to sustain a velocity grows with velocity cubed. Concept2's calibration, watts = 2.8 × (500/split)³, converts instantly: the canonical 2:00 split (120 s) is 202.5 watts, and holding it for the standard 2,000 m test returns 8:00.0 — the defaults on this page, and the score boundary generations of rowers have organized their winters around. The cube explains erg racing's central misery: improving a 2k from 8:00 to 7:30 (a 6.25% pace gain) demands 202.5 → 246 watts, +21% sustainable power — progress on the erg is bought at triple interest, which is why splits compress so stubbornly at the elite end (the men's 2k world record pace, ~5:35, is ~590 watts held six minutes).

Used as a training tool, the converter settles the two questions ergers actually ask. First, pacing targets: any goal time over any distance divides into the required split (goal seconds ÷ (distance/500)), and this page's total-time output inverts it just as fast for steady-state planning — a 10,000 m piece at a 2:10 split is 43:20 by the same multiplication. Second, intensity translation: watts convert cleanly to effort zones (a coach's "UT2 at 55–60% of 2k watts" is arithmetic, not vibes), and the split↔watt table exposes why equal split jumps aren't equal efforts — 2:10→2:00 costs +43 watts while 1:50→1:40 costs +87. One discipline the monitor can't give you: it measures flywheel power, not boat speed — on-water pace adds hull, crew synchronization and conditions, so erg watts are a fitness currency, not a promise about the river.

Worked Examples (Verified)

  • Defaults: 2:00 split → 202.5 W; 2,000 m → 8:00.0.
  • Steady state: 2:20 split (140 s) → 127.5 W; 30 min at it covers 6,429 m.
  • Elite reference: 1:35 split → 408 W — heavyweight international territory, sustained only in pieces, not tests.
  • Goal math: a 7:00 2k needs a 1:45 split = 302 W average — the number winter training is aimed at.

Erg Discipline

  • Compare watts across athletes, splits across races — the cube makes split differences lie about effort differences.
  • Drag factor, not damper setting, is the resistance variable that matters; the watts formula already accounts for the power you produced, whichever lever position you chose.
  • Pacing evenness is free speed: the cube punishes fly-and-die — a 1:50 first 500 in an 8:00 2k is repaid at punitive rates in the last 500.
  • Weight adjustment is a separate (contested) correction for on-water projection; raw erg watts need no adjustment to be a true fitness measure.
  • Verify with the PM monitor's own watts readout after a firmware-consistent calibration — the formula and the monitor should agree to the decimal.

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Frequently Asked Questions

How do you convert an erg split to watts?

With the Concept2 power law: watts = 2.8 × (500 ÷ split in seconds)³. A 2:00 split (120 s) gives 2.8 × (4.167)³ = 202.5 watts; a 1:45 split gives ~302 W. The relationship is cubic, so small split improvements cost disproportionately more power. This calculator converts your split to watts and projects your total time over any distance at that pace.

What is a good 2k erg time?

By population: for trained club rowers, men breaking 7:00 (1:45 split, 302 W) and women breaking 7:45 are strong benchmarks; 8:00 (the defaults here — 2:00 split, 202.5 W) is a solid trained-fitness line for men and a strong one for women; elite internationals live at 5:35–6:00 (men) and 6:20–6:45 (women), at 450–600 sustained watts. Age and weight class move every one of these — the honest comparison is against your cohort's percentiles, or better, against your own last test at the same drag factor.

Why does the erg use a cubic power formula?

Because hydrodynamic (and flywheel aerodynamic) drag force scales with the square of velocity, and power is force × velocity — hence velocity cubed. Doubling boat speed needs eight times the power; a 10% speed gain needs 33% more. The same physics governs real shells, which is why rowing speed differences look small while the fitness differences behind them are enormous, and why this calculator's watts column spreads athletes out far more honestly than the split column does.

What split do I need for a 7:30 2k?

Divide the goal by the number of 500 m segments: 450 seconds ÷ 4 = 112.5 s = a 1:52.5 split, which the cube prices at about 246 watts average. The general method — goal seconds ÷ (distance ÷ 500) = target split — works for any distance and any target; this calculator runs it in reverse (split and distance → total time), so enter 112.5 and 2000 to check any goal before you sit down.

Does drag factor change my watts?

No — and that's the point of the watts metric. Drag factor is the erg's measured resistance of your specific flywheel (affected by damper position, dust, altitude, machine age); the monitor uses it to compute power from flywheel deceleration. Two athletes at different damper settings producing 202.5 W are doing equal work — the split they earn is identical. Drag factor choice is about FEEL and stroke mechanics (heavyweights often 125–140, lightweights 110–125), not about making the number easier; the cube has no loopholes.

How far do I row in 30 minutes at a 2:20 split?

Distance = time ÷ split × 500: 1,800 s ÷ 140 s × 500 = 6,429 m. Steady-state (UT2) sessions are usually prescribed exactly this way — fixed time at a capped split or wattage — so the conversion on this page (enter your split and any distance, or solve for the distance your time and split imply) is the daily arithmetic of winter training logs. At 2:10 that same half hour yields 6,923 m; the cube says you paid ~27% more power for those 494 m.

Is erg pace the same as on-water pace?

No. The erg measures the power you deliver to a flywheel; a boat adds hull drag, crew synchronization, blade work, wind and current — an eight's shell speed at a given crew wattage follows its own (also cubic) physics with a different constant and shared across seats. Coaches use erg watts as the selection and fitness currency precisely because they're environment-free, then test boat speed on the water. Treating your erg split as your boat split will flatter you by roughly 10–15 seconds per 500 m in a single, less in big boats.

Is this erg calculator free?

Yes — free, instant, no sign-up. Enter your split in seconds and a distance for watts and projected total time.