To convert from the 12 point scale to the 4.0 scale you can use this table:

http://careers.mcmaster.ca/students/...nversion-chart

im a bit confused...i have to have a 11 for a 3.90...what about all the stuff in the middle about average and whatnot

What average? Do you mean the percentages?

ya the percentage stuff in the middle

That just means that for example at McMaster, if you get between 85 and 89 percent, you get an 11 in the course and therefore a 3.90. I am not sure about the other percentages though.

so is a 90+ a 12 or 95+? i've heard different things...

80-84.9 = 10
85-89.9 = 11
90+ = 12

There's a conversion table somewhere... hold on
http://careers.mcmaster.ca/students/...nversion-chart
So converting our Mac GPA (the 12 point system) to GPA (4 point system) is comparing Scale and column 10.
In terms of percentage to Mac GAP (12 point), it looks like it's column 3.
Letter grades would be column 7



Edit: Just a note, converting from percentage grades to the 4.0 system would result in the same 4.0 grade as if you use the Mac 12 point system to the 4 point system because schools (med school at least) will not average your percentages and then pick the gpa accordingly. They take the individual 4.0 grades for each course and then average them. For mac you'd covert the 12.0 to the 4.0 system and then average.

Ex. you get a 100 and a 50.
Average percentage: (100+50)/2=75 = 3.0 (using column 3 as it roughly corresponds to our mac system)
Average percentage the way they do it: (100+50)/2 = (4.0+0.7)/2 = 2.35
Average 12.0 mark : (12+1)/2 = (4.0 + 0.7)/2 = 2.35

As you can see, percentage to 4.0 gpa is the same as 12.0 gpa to 4.0 gpa because of the way they calculate averages. The way you'd WANT to do it giving you a full 0.65 gpa higher they won't let you :(

Again, this is for med schools at least. Not sure about other school.