Estimate your
aerobic ceiling
Enter your 2K erg time (or critical power) and body weight. Get an instant VO2 max estimate in mL/kg/min, plus the absolute L/min, a tier label, and a sex-graded percentile band, using the rowing-specific Hagerman equation.
Quick answer
Your 2K time (or critical power) tells us your steady-state wattage; multiply by 10.8, divide by body weight in kg, add 7. VO₂ = (10.8 × W / kg) + 7 in mL/kg/min. Trained adults pulling a 7:00 2K sit around 48; senior internationals at 6:00 push past 70.
Methodology
- Get watts. In From 2K Time mode, divide total seconds by 4 for the average 500m split, then watts = 2.80 / (split / 500)³ (Concept2 formula). In From Critical Power mode, your input is already watts.
- Watts → VO2. VO₂ (mL/kg/min) = (10.8 × W / kg) + 7 — the Hagerman rowing equation, derived on elite rowers.
- Relative → absolute. Multiply by kg and divide by 1000 for the L/min reading.
- Sex-graded percentile. Compare the relative score against general-population ACSM norms for your selected sex; the percentile band is the only output that depends on the sex toggle.
Tier reference
| Tier | VO2 (mL/kg/min) | Typical 2K (80 kg) | Description |
|---|---|---|---|
| World class | ≥ 75 | Sub-5:52 | Olympic / national-team territory. Rare. |
| Elite | 65 – 75 | 5:52 – 6:14 | Senior international, top D1. |
| Competitive | 55 – 65 | 6:14 – 6:38 | Strong club / collegiate lightweight. |
| Recreational | 45 – 55 | 6:38 – 7:10 | Solid masters / club fitness rower. |
| Untrained | 35 – 45 | 7:10 – 7:56 | Healthy adult baseline. |
| Below average | < 35 | Slower | Aerobic base under development. |
“Typical 2K” assumes an 80 kg athlete. Heavier athletes can post the same 2K time at a lower relative VO2; lighter athletes at the same time score higher relative.
Frequently asked questions
What formula does this calculator use?
The Hagerman (1978) rowing-specific equation: VO2 (mL/kg/min) = (10.8 × watts / kg) + 7. Watts come either from your critical power input directly, or from your 500m split via the Concept2 formula watts = 2.80 / (split_seconds / 500)³. The Hagerman equation was derived on elite rowers and is the rowing-community standard, slightly different from generic ACSM formulas built around running.
When should I use "From 2K Time" vs "From Critical Power"?
Use From 2K Time when you have a recent honest 2K time trial — that's what most rowers track. Use From Critical Power when you've done a 3-minute test (3MT) or a CP estimation protocol and want VO2 from the steady-state aerobic ceiling rather than a maximally-paced race that includes anaerobic contribution. The CP-based estimate is usually 2–4 mL/kg/min lower than the 2K-based one for the same athlete because CP excludes the W′ anaerobic reserve.
How accurate is a 2K-derived VO2 max?
For a maximally-paced 2K it correlates strongly (r ≈ 0.85+) with directly-measured VO2 max in trained rowers. The estimate is most reliable when the 2K was an honest time-trial effort within the last few months. A pacing failure (positive split, blow-up at 1500m) understates the score; a fresh PR slightly overstates because anaerobic contribution to the 2K is real but the equation treats all power as aerobic.
How is the sex toggle used?
The Hagerman formula itself is sex-neutral — it works on watts and kilograms. The sex toggle only changes the percentile-band reference values (general-population ACSM norms differ between men and women). Your absolute VO2 number does not change when you flip Male / Female; only the population-percentile read-out does.
How should I use the result?
Track it across a season as a long-term aerobic-ceiling metric. A rising number with stable training load means your engine is growing. A flat number despite good training suggests bottlenecks elsewhere (technique, anaerobic capacity, lactate clearance). The absolute number matters less than the trend.
Why is my number different than other online VO2 max calculators show?
Most generic online calculators use sex-and-age-graded running formulas that overshoot for rowers because rowing is more efficient per watt than running. The Hagerman rowing equation is the rowing-specific honest number for erg-derived estimates. Treadmill VO2 max tests typically come in 5–10% higher than this estimate in the same athlete because the runs use more accessory musculature.
Is this suitable for masters athletes?
Yes — the formula has no age term, so the raw output stays comparable across decades. For competition tier comparison, masters athletes typically benchmark against the same elite / competitive thresholds as open athletes. Age-grading is best done at the 2K-time level (using USRowing handicaps) rather than at the VO2 stage.