Erg Pace Calculator

Turn a 1 km SkiErg or RowErg time trial into easy, threshold and race pacing bands — worked in watts, the way the machine actually behaves.

Provisional · n = 1 coefficients

Start here

One erg time trial is enough. Everything else sharpens it.
1 · Your erg time trials

Fill in either, or both. Each machine is worked out on its own — a ski time never borrows from a row time. Type it however you like: 3:36, 3.36 and 336 all mean three minutes thirty-six.

2 · Your running (optional)

This is what separates an athlete whose erg time comes from raw power from one whose comes from an aerobic engine. The two need different bands off the same time trial. Leave it blank and we assume you sit at the reference.

Why the ski gets one band and the row gets two

The SkiErg is station one. You arrive at it fresh, and the rest of the race is still in front of you — so it should be raced at threshold, not above it. Going harder buys a handful of seconds and mortgages the next fifty minutes. That is why the ski shows a single combined race-and-threshold band rather than a race band sitting above it.

The row is station five. It lands with the sled push, the sled pull and the burpee broad jumps already in your legs. Racing it at the pace you can hold on a fresh threshold set is not realistic, so the row keeps a separate, deliberately slower race band underneath its threshold band.

What the aerobic index actually measures

Two athletes can post the same 1 km erg time by completely different routes. One is strong and powerful over four minutes; the other has a large aerobic engine. Their time trials match, but the fraction of that power they can hold for forty minutes does not — so the same band percentages would be wrong for at least one of them.

Comparing a 2 km run against the erg time trial separates the two. We take the ratio run 2 km ÷ erg 1 km and compare it with a reference ratio (1.93 for ski, 2.04 for row). A runner who is quick relative to their erg scores above 1.00 and gets a higher share of time-trial power as critical power; a power-dominant athlete scores below 1.00 and gets less. The index is clamped to 0.85–1.18 so an odd test can't produce an absurd band. Leave the run blank and it sits at exactly 1.00.

Where critical power comes from

Critical power is the highest power you can hold more or less indefinitely — the boundary above which fatigue becomes a clock rather than a feeling. It is the single number every band here is a percentage of.

A 1 km time trial is roughly a three-to-four minute effort, so it sits well above critical power. We estimate the gap with a multiplier: 0.78 × AI^0.4 for ski, 0.72 × AI^0.4 for row, clamped to 0.72–0.84 and 0.66–0.78 respectively. The ski multiplier is higher because a 1 km ski is a longer effort than a 1 km row, so it already sits closer to critical power.

A sharper version, if you'll do a second test

The multiplier above is an assumption. It can be replaced with a measurement: add a 4 km time trial on the same machine and the two efforts solve critical power and W′ directly from the power–duration relationship, with nothing estimated. That is the upgrade path for this tool, and the single-test route will stay as the default because most people will only ever do one.

How much should you trust this?

Less than you'd trust the running calculator, and the difference matters. The pace-to-power conversion is Concept2's own and is exact. Everything after it — the reference ratios, the multipliers, the band percentages — is fitted on a single athlete and is provisional. The reference ratio in particular is an n = 1 estimate.

So these are starting points for prescription, not measurements. They are built to stop you training every session at the same middling intensity, which is the actual problem most people have. If a band feels plainly wrong once you're on the handle, it probably is — move it, and trust the session over the spreadsheet.