Grade Letter Converter

How grade scales actually work

The letter grade system in the US dates to the early 1900s, but the specific cutoffs you encounter depend entirely on your school and your professor. Two dominant systems exist: the simple A/B/C/D/F scale (five grades, cutoffs every 10 points) and the plus-minus scale (thirteen grades, cutoffs roughly every 3 points starting at each decade).

The plus-minus system is more common at universities because it gives professors finer resolution. A student who earns 88% is meaningfully different from one who earns 85% on a plus-minus scale (B+ versus B). On a standard scale both are just B.

How letter grades map to GPA

GPA converts letter grades to numbers. On the standard 4.0 scale, each letter grade has a fixed point value. Multiply each course grade by its credit hours, add those products, then divide by total credit hours. That quotient is your GPA.

A+ is capped at 4.0 at most schools. The difference between an A and an A- (4.0 versus 3.7) spans 0.3 GPA points. Missing that A by one point at 89.99% costs you a full tier on the plus-minus scale.

Common questions

• Does every professor use the same cutoffs? No. Some curve; others use 93/83/73/63. Your syllabus is the authoritative source. This converter uses the most common US university defaults.
• What happens if my school rounds? If your school rounds 89.5 to 90, you get an A- (3.7) instead of B+ (3.3). That difference compounds across a semester.
• Why is there no standard A+ on the simple scale? On a 5-grade scale, all scores above 90 collapse into one A. Plus-minus subdivides that into A+, A, and A-.