No, although many universities America have the 4.0 GPA system, the percentages required are very different, and each university or state makes there own policies for there grading.
America:
Grade Percentage GPA value
A 90-100 3.5-4.0
B 80-89 2.5-3.49
C 70-79 1.5-2.49
D 60-69 1.0-1.49
F 0-59 0.0
A+ = 98-100= 4.0 GPA (can be higher if advanced courses taken!)
A = 93-97 = 4.0
A- = 90-92 = 3.67
B+ = 88-89 = 3.33
B = 83-87 = 3.0
B- = 80-82 = 2.67
C+ = 78-79 = 2.33
C = 73-77 = 2.0
C- = 70-72 = 1.67
D+ = 68-69 = 1.33
D =63-67 = 1.0
D- = 60-62 = 0.67
F = <59 = 0
BUT: as I said, this is not the same across America, but just the most common.
Monash:
Grade Percentage GPA value
High Distinction (HD) 80 - 100% 4
Distinction (D) 70 – 79% 3
Credit (C) 60 – 69% 2
Pass (P) 50 – 59% 1
Fail (F) <50% 0.3
Withdrawn Fail 0
EDIT: damn Fyrefly!