About the Grade Calculator
Converting raw points earned into a percentage and letter grade is simple, but our Grade Calculator does it instantly with a standard letter grade scale applied automatically.
How It Works
The calculator divides points earned by total points possible to find a percentage, then maps that percentage onto a standard letter grade scale (A, A-, B+, B, and so on) using commonly used grade boundary thresholds.
Formula & Methodology
Converting points earned to a percentage normalizes any point scale (out of 20, 50, 100, or any other total) onto the same universal 0-100 basis, which is what makes it possible to map onto a single consistent letter grade scale regardless of how many total points a specific assignment was worth. The letter grade mapping itself is a lookup table of percentage boundaries (like 90-100% = A, 87-89% = B+, and so on) applied to that normalized percentage.
Step-by-Step: Calculating It By Hand
- 1Divide points earned by total points possible.
- 2Multiply by 100 to express the result as a percentage.
- 3Compare that percentage against the letter grade scale's boundary thresholds to find the corresponding letter grade.
Examples
Standard case
88 points earned out of 100 total gives a percentage of 88% and a letter grade of B+.
Different point scale
The same percentage calculated from a different point scale - say, 44 out of 50 - still correctly produces the same 88% and B+ letter grade.
Advantages
- Converts any points-earned-out-of-total into both percentage and letter grade instantly
- Uses a standard, commonly applied letter grade scale
- Works for any point scale, not just out of 100
- Fast way to check a grade calculation
Common Mistakes
- Using a different letter grade scale than your specific school or class actually uses, since thresholds can vary by institution
- Confusing weighted grade calculations (where different assignments count differently) with this simple points-based calculation
- Not accounting for extra credit points that might push a score above the total points possible
- Assuming the standard letter grade scale used here matches every grading system exactly
Edge Cases to Watch For
- Letter grade boundary thresholds vary somewhat between institutions - a percentage right at a boundary (like exactly 90%) could fall into different letter grades depending on the specific scale used.
- A percentage above 100% (from extra credit) needs special handling depending on whether the grading scale allows for grades above the standard maximum.
- This calculates a single assignment's percentage - a full-course grade typically requires combining multiple assignments through a Weighted Average or GPA calculation instead.
- Some schools use plus/minus letter grades (B+, B, B-) while others use only whole letter grades, affecting how finely the percentage-to-letter mapping is divided.
Common Use Cases
- Quickly converting points earned into a percentage and letter grade
- Checking a grade calculation on a specific assignment or test
- Understanding where a score falls on a standard grading scale
- General classroom and coursework grade tracking