Power Zone Calculator (Rebuilt)

Another old tool that survived the rebuild — calculate your Peloton FTP power zones.

2026-03-22

This is a companion piece to the Strava to Garmin post.

When I rebuilt hiimandy.com, I broke another small tool that people were still using — a Peloton FTP Power Zone calculator.

The original version was a single HTML page with jQuery and Bootstrap. It's been floating around since I posted it on Reddit years ago, and based on traffic logs, people are still finding it.

I've rebuilt it here: /engineering/projects/power-zone

Same idea as before:

Enter your 20 minute average output
Get your FTP and all seven power zones
No accounts, no tracking, nothing stored

If you were using the old version and it disappeared — sorry about that. It's back now.