Extrude precision

Question

I'm trying to extrude faces in a precise amount, I tried doing so using Extrude -> Right click, and then Alt + S, and hitting 0.3 (for 30 cm), the offset number seems right, but the amount of extrusion is definitely not, I used the Ruler to measure it and it was 51 cm, am I doing something wrong here?

Answer 1

OK, I guess I found the answer, I needed to freeze the object scale using Ctrl + A before applying the Extrude