ErgSwap: Cardio Converter
Run, Row, Ski & Bike Swaps
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Programmed 1,000 m on the rower but they're all taken? ErgSwap gives you the equal-effort swap on whatever your gym has free: run, SkiErg, BikeErg, Echo, Assault.
Programmed for one machine, stuck with another?
The whiteboard says row 1,000 m and every rower is taken. Or your knee isn't up to running today. Or your gym simply doesn't own a SkiErg. ErgSwap tells you what to do instead: the equal-effort piece on whatever cardio is actually free.
Enter the workout as it was written. Read the answer off every other machine in the gym. One number per row, in the unit that machine's console actually shows.
HOW IT WORKS
• Tap the machine the workout was programmed for, enter the distance or calories, and every other machine's equivalent appears at once.
• Tap any result to turn it around. Decide to row instead and ErgSwap re-converts everything from 500 m row.
• Quick-entry presets for the amounts you use most — a distance ladder and a calorie ladder, whichever matches what you're entering — or step the amount up and down. Set your own presets in Settings.
• Share the whole answer as plain text. One tap sends every machine's equivalent to the group chat, in a message any app can display.
EVERY ERG IN THE GYM
• Run — track, road, or curved treadmill
• Concept2 RowErg and Rogue Echo Rower
• Concept2 SkiErg and Rogue Echo SKI
• Concept2 BikeErg
• Rogue Echo Bike
• Assault AirBike
Turn off whatever your gym doesn't have and it disappears from the list.
THE RIGHT UNITS, PER MACHINE
Each machine reads in what its own console shows, so the number on your phone is the number you dial in. Meters on the ergs. Miles on the air bikes — but calories first, because calories are how air bikes get programmed. "20 cal Echo" is the workout; nobody rides an Echo to 0.54 mi.
The Echo and the Assault are tracked separately, not lumped together as one "air bike." The Echo is meaner — roughly 30% fewer calories for the same effort — and rounding that away would cost you a minute on the clock.
WOMEN'S AND MEN'S COLUMNS
The published conversions differ by column, and the gap is real: a 400 m run is 400 m of rowing on one and 500 m on the other. ErgSwap starts with both, paired on every row the way the printed chart does — "400 / 500 m", women's first — so a coach can read one screen for a mixed class. Reading just your own number is one tap: the selector sits right on the results card — women's, both, or men's — and every number follows it.
SCALED OR FLAT
• Scaled follows the published chart, which compresses back toward running over longer pieces. This is the one you want at 5 k.
• Flat uses a single ratio per machine — 400 m run ≈ 500 m row ≈ 1,000 m BikeErg. Easy to do in your head, but it overshoots past about a mile, and ErgSwap tells you the moment that starts to matter.
Built on CrossFit Affiliate Programming's published cardio conversion charts, transcribed exactly and shown as published.
No account. No ads. No subscription. No tracking. Every conversion is worked out on your iPhone; the only thing the app sends is optional, anonymous usage stats, and those are off with one tap in Settings.
Ratings & Reviews
• Polish and under-the-hood improvements.
The developer, STEPHEN P JOHNSTON, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- STEPHEN P JOHNSTON
- Size
- 3.3 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Steve Johnston