The GPA scale explained

Nearly every American school converts letter grades into points on a four point scale, then averages those points using credit hours. The tables here cover the versions you are most likely to meet, along with the percentage ranges that usually sit behind each letter.

Standard unweighted 4.0 scale

This is the default almost everywhere. An A is worth four points, each step down the alphabet costs a full point, and the plus or minus adjusts by three tenths. An A+ earns the same four points as a plain A on this version.

LetterPercentage4.0 scale4.3 scale
A+97 to 1004.04.3
A93 to 964.04.0
A-90 to 923.73.7
B+87 to 893.33.3
B83 to 863.03.0
B-80 to 822.72.7
C+77 to 792.32.3
C73 to 762.02.0
C-70 to 721.71.7
D+67 to 691.31.3
D63 to 661.01.0
D-60 to 620.70.7
FBelow 600.00.0

Weighted scale for honors and AP

High schools that weight their grades add points on top of the base value for harder courses. Half a point for honors and a full point for AP or IB is the most common arrangement, which is what pushes weighted averages above four and gives the scale a practical ceiling of five.

LetterRegularHonorsAP / IB
A4.04.55.0
B3.03.54.0
C2.02.53.0
D1.01.52.0
F0.00.00.0

Notice that an F stays at zero across all three columns. Schools do not hand out bonus points for a class you did not pass, however demanding it was, and any calculator that tells you otherwise is giving you a number your registrar will not recognise.

Where these numbers stop being universal

Percentage boundaries are the least consistent part of the whole system. Some schools set an A at ninety and above with no plus or minus at all, others run a ten point scale where a B starts at eighty, and a few use seven point bands that shift everything. Your syllabus or student handbook is the authority, and if the numbers here disagree with it, trust the handbook.

International grades are a separate matter again. A first class degree in the United Kingdom, a one point zero in Germany, and a nine out of ten in India all mean excellent work, but none of them convert cleanly into a four point GPA. Universities that accept international transcripts run them through a credential evaluation service rather than a conversion table, so treat any online converter as a rough guide.

Once you know which scale applies to you, the college GPA calculator and the high school version both let you switch between the plain and weighted setups with one toggle.