Drag Factor Calculator

By the Watta Team · Updated 9 October 2026

Pick a machine and a damper setting to get a rough drag factor. On a clean RowErg, damper 4 is roughly 127 and damper 5 roughly 142 — the PM5 shows the real number.

Drag Factor Estimator

Machine:

Damper:5

Estimated Drag Factor≈ 142Moderate — balanced between rate and powerTypical training range for the RowErg: 110–140

A rough estimate for a clean machine at sea level — a dusty fan cage, altitude and temperature all move it. The real number is on the PM5: More Options → Display Drag Factor.

Rowing this later? Watta logs the real piece from a photo of your PM5 — free on iPhone.

Approximate drag factor at each damper setting

Computed with the same functions as the calculator above, so the two cannot disagree.

Damper	RowErg	SkiErg	BikeErg
1	80	60	30
3	111	91	46
4	127	107	53
5	142	122	61
7	173	153	77
10	220	200	100

Estimates only, interpolated between the damper-1 and damper-10 figures for a clean machine at sea level (RowErg 80–220). A dusty flywheel or altitude moves them a long way — read the real number off the PM5 under Display, More Options, Drag Factor, and set the damper to hit it.

Choosing an app?

Which app should you use with your Concept2? →

Seven erg trackers ranked, free options first: ErgData, the Concept2 Logbook, Watta and more — what each is best for.

About This Calculator

The drag factor calculator gives a rough estimate of the resistance the flywheel experiences on a Concept2 ergometer at each damper setting. Drag factor (a number the PM5 can display) is not the same as the damper setting — the damper lever controls how much air enters the fan cage, while drag factor is the resistance the monitor actually measures from how quickly the flywheel slows down. The same damper setting gives different drag factors depending on how clean the fan cage is, altitude, temperature and machine wear, which is why the estimate here is approximate. Most rowers train at a drag factor somewhere between 110 and 140 on the RowErg, which typically corresponds to damper 3–5 on a well-maintained machine. Higher drag feels like a heavier boat; lower drag feels like a lighter one.

How This Works

Select your machine (RowErg, SkiErg or BikeErg) and damper setting. The calculator interpolates between typical drag factor readings at damper 1 and damper 10 for that machine on a clean machine at sea level. For the real figure, check More Options → Display Drag Factor on your PM5 while rowing — it takes a few strokes to settle.

Formula

Drag factor ≈ drag_at_damper_1 + (damper − 1) / 9 × (drag_at_damper_10 − drag_at_damper_1)

Examples

RowErg at damper setting 4

Estimated drag factor of roughly 127 on a clean machine — inside the range most rowers train at.

RowErg at damper setting 7

Estimated drag factor of roughly 173 — heavier than most rowers use; it tends to slow the rate and load the lower back.

SkiErg at damper setting 5

Estimated drag factor of roughly 122 — within the typical range for general SkiErg training.

Worked examples are generated from the same formulas as the calculator above.

Benchmarks

Level	Value
RowErg — typical training range	110–140 (about damper 3–5)
RowErg — lighter setting	100–120 (about damper 2–4)
SkiErg — typical range	100–130 (about damper 3–6)
BikeErg — typical range	40–70 (about damper 3–6)
Real figure	PM5 → More Options → Display Drag Factor

More reference tables — 2K, 5K and 500m standards, watts by level, stroke rates and a split-to-watts table — are on the Stats & Benchmarks page.

In the Watta App

Watta records the drag factor when it is visible in your PM5 photo and stores it with the piece, so you can see how your splits vary with the setting over time.

Frequently Asked Questions

What drag factor should I use for rowing?

Most rowers do well between 110 and 140 on the RowErg. Beginners often start around 100–120. Larger, stronger athletes sometimes go higher for short pieces. The guiding principle: it should feel like rowing a boat on flat water, not pulling through mud.

Is a higher damper setting better?

No. A higher damper raises drag, which changes the feel — heavier catch, slower flywheel — but it does not make the workout "harder" in a useful sense, and it tends to lower stroke rate and increase strain on the lower back. Concept2 suggests damper 3–5 for most rowers. Setting the damper to 10 is a common beginner mistake.

Why does the same damper give different drag factors on different machines?

Drag factor depends on airflow through the fan cage, which is affected by dust, altitude (air density), temperature, humidity and wear. A dusty cage restricts airflow and lowers drag factor. Cleaning the cage periodically and checking the drag factor on the monitor keeps sessions comparable across machines.

What drag factor is used in competition?

Indoor rowing competitions generally let athletes set their own damper (and therefore drag factor) within the event rules, and the PM5 records the drag factor with the result. Check your event's rules; many rowers race close to the drag factor they train at.

Which Rowing App Should You Use?

Best Rowing Apps for Concept2Watta, ErgData, the Concept2 Logbook and Strava compared for logging, rankings and analytics.Best Rowing Apps 2026Every rowing app worth using, sorted by what you actually want from it.Concept2 Logbook AlternativesWhat the official logbook records, what it misses, and whether to run both.ErgData AlternativeLog your erg from a photo of the PM5 — no Bluetooth pairing needed.

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