Power Fx function
Text, math, and dates
Len
Counts characters in text.
What it does
Counts characters in text.
The job: Everyday formatting and calculation, from Concatenate to DateDiff.
How to use Len
Start from the task, not the alphabet. If you are shaping rows for a gallery, reach for Len alongside the other data functions in its group; if you are saving, navigating, or changing state, use it on an event such as a button OnSelect rather than in a display property. When a formula misbehaves, check for a blank value where you expected text, then confirm the behaviour against the examples in the Power Fx function reference hub.
New to the language itself? Read What Is Microsoft Power Fx? first, then come back here when you need this specific tool.