Workout file converter
Drop in a Zwift .zwo, an .erg or an .mrc file and
get the other three back, plus a plain text version you can read on a phone. It all happens inside your
browser — the file never leaves your computer, there is no upload, no account and no limit
on how many you convert.
Drop a workout file here
.zwo · .erg · .mrc — one at a time
.erg and the text file, which are
written in absolute watts. .zwo and .mrc carry percentages.
Nothing loaded yet.
· the profile is drawn from the file itself, so if it looks wrong here it will feel wrong on the trainer.
Take it in any format
A format marked same as the file you dropped is still offered — converting a file to its own format is a quick way to clean it up or rename it.
Which format does my app want?
| App | Format | How it gets there |
|---|---|---|
| Zwift | .zwo | Documents/Zwift/Workouts/<your ID>/, then restart |
| MyWhoosh | .zwo | through the web portal |
| Rouvy | .zwo | workout builder on the website |
| TrainerRoad | .erg / .mrc | Workout Creator → import |
| Wahoo SYSTM | .erg / .mrc | custom workout import |
| Most others | .mrc | look for "import workout" |
If your app reads something else, tell me which one and which format and I will add it. That is how this tool got built in the first place.
What is the difference between .zwo, .erg and .mrc?
- .zwo — Zwift's own XML format. Power is a fraction of your FTP, so the app scales it to you. It also understands ramps, repeated intervals and free-ride blocks as structure rather than as a list of points.
- .mrc — an old, plain interchange format. A list of times and percentages of FTP. Almost every trainer app reads it, and because it is relative it never goes stale.
- .erg — the same list, but in absolute watts. Simple and universal, and wrong the moment your FTP changes. Prefer .mrc when your app accepts both.
Converting from .zwo to .erg or .mrc flattens the structure
into points, which every app handles. Going the other way, this converter turns each block back into a
steady or ramping segment, so the result is a proper Zwift workout rather than one long ramp —
the duration, the intensity factor and the TSS come back identical.
One thing genuinely cannot survive the trip: a free ride block has no power
target, and .erg and .mrc have no way to say "no target". It is written out
at 60% of FTP, so convert in that direction only when you do not mind losing it.
What happens to my file?
Nothing leaves your browser. There is no server doing the conversion: the file is read locally, converted in JavaScript, and handed straight back to you as a download. Close the tab and it is gone. No account, no upload, no copy kept anywhere.
The only thing this site records is an anonymous count that a conversion happened, the same as for any other page. No file names, no contents. How that works.
Where this came from
I built it for myself while putting a 16-week plan into apps that each wanted a different format. The existing options were command-line tools on GitHub and one paid app — fine if you write code, useless if you just want to ride.
Want a whole plan rather than one file? The plan is free in every format on this page.