Erg Calculator - Solve Any Erg Field

An erg calculator is a four-field solver for indoor rowing machines. Enter any two of distance, total time, 500m split, and average watts to recover the other two. It uses the cubic power model Concept2 publishes, so 1:50.0/500m maps to about 263 W and a faster split always needs more watts.

• • Pacing a 2k or 5k piece: Enter your goal split and distance to recover the total time and watts to hold.
• • Translating watts into a split: When a coach programs a workout in watts, enter watts and distance to recover the 500m split.
• • Working out a 2k time from a watts target: Type distance and watts to recover the 2k split and total time.
• • Planning a steady-state row: Use watts and the planned duration to recover the meters and split.

The 500m split is total time scaled to 500 m (split = 500 x time / distance), and the watts curve follows Watts = 2.8 / (Split / 500)^3. The numbers match Concept2's chart.

For runners who combine erg sessions with road running, the running pace calculator returns the per-kilometer and per-mile splits needed for those sessions. Rowing watts and running pace use different models.

The erg calculator works in two stages: a linear ratio links distance, time, and 500m split, then the Concept2 cubic power model translates any split into watts. Enter any two fields, leave the others at zero, and the result panel shows all four values. You can also re-enter the recovered watts with a new distance to project that profile onto a different piece length.

• distance: Total meters covered. Used with time or split to recover the other variables.
• time: Total time in seconds. Renders as HH:MM:SS.S to match the monitor.
• split: 500m split in seconds (e.g. 110 = 1:50.0). The pace metric the watts model is anchored on.
• watts: Average mechanical power, computed from split via the cubic Concept2 model.

Watts and split are linked by a cubic curve, so a one-second improvement from 2:00.0 to 1:59.0 raises watts by about 6 W, and from 1:50.0 to 1:49.0 by about 8 W. The cubic relationship is fixed by Concept2, so the same split on the same monitor always reads the same watts regardless of damper. Per-stroke variation comes from stroke length, stroke rate, and flywheel handling, so compare with the monitor's reading rather than assuming a fixed percentage match.

According to Concept2 Pace Calculator, the relationship between 500m split and average power follows Watts = 2.8 / (Split / 500)^3, the cubic model used in their official pace calculator.

As a complementary intensity cue, the target heart rate calculator works out age-based heart-rate zones. Read those alongside the watts output as a separate effort signal, since watts and heart rate are not interchangeable.

Four small ideas explain every result, and they line up with how a Concept2 monitor reports numbers.

These definitions matter because the curve is non-linear near the fast end of the scale. A one-second drop near 1:30.0 changes watts by more than 13 W, while the same drop near 2:30.0 changes it by less than 4 W.

According to Wikipedia Rowing ergometer, the term ergometer combines the Greek ergon (work) and metron (measure), and the indoor rower is the most common ergometer used for fitness and indoor rowing training.

For rower-specific view that adds body weight, the rowing split calculator uses the same Concept2 watts anchor and adds calories per hour and weight-adjusted scores.

Five short steps turn any two known erg numbers into the full set of distance, time, split, and watts.

1. 1 Pick the two values you know: Decide which two of the four fields you can read off the monitor. The most common pairs are distance and time, or split and watts.
2. 2 Enter those values, leave the others at zero: Type seconds for time and split, meters for distance, watts for power. Zero means solve-for-me; non-zero values must sit inside the allowed range.
3. 3 Read the recovered values: Time renders as HH:MM:SS.S (or MM:SS.S for sub-hour pieces), split as MM:SS.S, distance and watts as whole numbers.
4. 4 Pace your next piece with the split: Lock the recovered pace on the monitor and hold it across intervals. On a Concept2, the same split always reads the same watts, so a noticeable difference from the cubic prediction usually points to stroke length, stroke rate, or flywheel handling.
5. 5 Cross-check the watts against the monitor: Differences of more than 2-3 percent usually point to stroke technique or a different flywheel design, not a calculation error.

Imagine you just finished a 5,000 m piece in 20:00.0 (1,200 seconds). Type 5000 into distance and 1200 into time, leave split and watts at 0, and the panel shows a 2:00.0/500m split and 203 W. For the 2k version, type 2000 into distance and 203 into watts with time and split at 0, and the panel shows a 1:59.9/500m split and 7:59.6 total time.

For aerobic capacity context, the VO2 max calculator estimates VO2 max from a Cooper or Rockport field test. The erg watts and the VO2 max estimate are independent inputs.

A purpose-built erg solver removes the small but consistent errors that come from doing the math in your head or in a spreadsheet.

• • Matches the monitor to the second: The split and watts outputs use the Concept2 cubic anchor, so the result agrees with the Performance Monitor.
• • No mode picker to learn: The fill-any-two logic figures out which formula to apply from the inputs.
• • Reads back in the format you expect: Total time renders as HH:MM:SS.S for longer pieces and MM:SS.S for short ones, and the 500m split renders as MM:SS.S to match the Concept2 display.
• • Built around the Concept2 anchor: The cubic relationship is the standard reference for indoor rowing power, and the calculator uses the same 2.8 anchor. Other ergometers may scale watts differently, so a small monitor offset is normal.
• • Helps you pace without re-doing the math: When the workout is programmed in watts, the tool converts to a split on the spot. When it is programmed in split, the tool returns the watts target.

These advantages compound for users who also wear a heart-rate monitor. The cubic relationship is fixed on a Concept2, so the same split always reads the same watts, but per-stroke variation from stroke length, stroke rate, or flywheel handling shifts the monitor's reading, so read the watts output as a target band.

For runners who combine erg work with road races, the marathon pace calculator plans per-kilometer splits and finish times for the running leg. Rowing watts and running pace use different models.

Three factors dominate the result, and limitations tell you when to sanity-check the number with your monitor.

• • The cubic model assumes a Concept2-style flywheel. Magnetic or water-resistance machines may show a few watts of offset because the curve is anchored on the Concept2 flywheel calibration.
• • The tool treats watts as an average across the whole piece. Monitors also report per-500 m split watts, useful for intervals but not for total-piece math.

Treat the watts output as a target band. The cubic model is fixed on a Concept2, so the same split always reads the same watts regardless of damper; differences usually come from stroke technique, flywheel handling, or a different flywheel design.

The fill-any-two workflow stays straightforward: enter any two of distance, time, 500m split, and watts, and the panel recovers the other two.

If you cross-train on a stationary bike, the calories burned biking calculator estimates ride calories from body weight, speed, and MET-based effort. Bike and erg use different calorie models.