Workout builder — type it, ride it

Describe a session the way you would say it out loud — 15 min warmup, 3x10 min at 90% with 5 min easy, 10 min cooldown — and get it as a file your trainer app can ride. It is a parser, not a chatbot: it runs in your browser, costs nothing, has no limit and no account, and it shows you exactly what it understood so you can fix it before downloading.

Your session

Try one

Name FTP W

This is what it understood

Every block is editable. Change a number and the profile above changes with it — the file you download is always what you see here, not what you typed.

Duration	From	To	At your FTP

Take it

What it understands

Repeats — 5x5 min, 3 x 10m, 6x30 sec.
Durations — 10 min, 15m, 90 sec, 1.5h. Seconds, minutes and hours all work.
Power as a number — @ 110%, at 90% FTP.
Power as a name — recovery 50%, easy and endurance 65%, tempo 80%, sweet spot 88%, threshold 98%, VO₂max 110%, anaerobic 130%, sprint 150%. Zone numbers z2 to z7 work too.
Recovery — anything after with, w/ or a slash: with 3 min recovery at 50%, w/ 5m easy, / 30 sec easy.
Warmup and cooldown — written as ramps rather than flat blocks, because that is what they should be. A warmup climbs from 50% to 75% unless you give it a number.

Separate the parts with commas or new lines. Anything it cannot read is listed above the profile rather than quietly ignored.

Why it does not use AI

Because it does not need to. Every example on this page is a regular pattern — a count, a duration, a power, a recovery — and patterns are what parsers are for. That has three consequences you can feel:

It is free and stays free. Nothing is generated on a server, so there is no cost per use and therefore no "free to try" ceiling waiting for you.
It is instant and redraws as you type, instead of making you press a button and wait.
It is predictable. The same sentence always gives the same workout, and when it misreads something it says so, rather than inventing a plausible-looking session.

The trade is that it only understands the shapes listed above. If you write a paragraph of prose it will miss things — which is exactly why the blocks are editable.

Already have a file?

If what you need is to turn an existing .zwo into .erg or .mrc, or the other way round, that is the workout file converter — same approach, also entirely in your browser.

And if you want a whole structured plan rather than single sessions, the 16-week plan on this site is free in every format.