I have always been puzzled and confused of these two phrases: "Fill-up" and "Fill-out". Whenever I go to the Professional Regulations Commission (PRC), I am always instructed to FILL-UP the forms. It even has a big instructions posted on the wall stating to FILL-UP the forms completely. I even hear professionals use the phrase. I always see such also in many of the forms from both private and public entities. But, a teacher of mine told me to use FILL-OUT instead. Why should the preposition be changed?
1 2
Comments  (Page 2) 
Thanks Nona!

Maybe the 'out' means fill until you run OUT of blanks/space. It doesn't really matter but every bit helps me understand
fill up is wrong when you are going to use it in forms. fill out is correct
Students: We have free audio pronunciation exercises.

Because hearing something said everyday does not make it right.