Average Grade Calculator: Percents, Letters or Both

Sometimes you just have a list: a few test percents, a couple of letter grades from the portal, a quiz written as 18/20. This calculator reads all of them, puts them on the same percent scale, and averages them — with or without weights.

How to type your grades

Put one grade per line, or separate grades with commas. Each grade can be:

• A percent: 92 or 92%
• A letter: B+, A-, C (lowercase works too)
• Points: 18/20, which becomes 90%

To weight a grade, add a space or an “x” and the weight after it: 85 x3, 85 3 or A- x2. Anything the calculator can’t read shows up in the table as “skipped,” so nothing gets silently dropped. Tick Remember my list to keep the list in this browser for next time; it is never put in the page link.

How letters turn into percents

A letter covers a range, so it has to be turned into one number before it can be averaged. The calculator offers two choices on the standard plus/minus scale:

“Middle” is the fairer guess when you don’t know the exact percent. “Lowest” is the cautious choice: it tells you the least the letters could be worth.

Worked example: simple vs. weighted

The calculator starts with six grades: 92, B+, 78, A− (weight 2), 18/20 and 85 (weight 3).

1. Convert: 92, 88.5, 78, 91.5, 90, 85.
2. Simple average: (92 + 88.5 + 78 + 91.5 + 90 + 85) ÷ 6 = 525 ÷ 6 = 87.5%.
3. Weighted average: 92 + 88.5 + 78 + 91.5 × 2 + 90 + 85 × 3 = 786.5. The weights add to 9, so 786.5 ÷ 9 = 87.39%, a B+.
4. Median: sorted, the grades are 78, 85, 88.5, 90, 91.5, 92. The middle two are 88.5 and 90, so the median is 89.25%.
5. Range: 78 to 92, a spread of 14 points.

The weighted average is a bit lower than the simple one because the 85 counts three times. The median is higher than both because the single 78 pulls the averages down but not the middle.

How do you average letter grades? Three conversions, two answers

Averaging letter grades means choosing what each letter is worth first, and that choice can change the final letter. Take five letters from one term: A−, B+, B, C+ and A. In the weighted version, the B is a test that counts three times and the A a project that counts twice (weights 1, 1, 3, 1, 2).

The same five letter grades averaged three ways (standard plus/minus scale)

The arithmetic for the default row: (91.5 + 88.5 + 85 + 78.5 + 95) ÷ 5 = 438.5 ÷ 5 = 87.7%. Weighted: (91.5 + 88.5 + 85 × 3 + 78.5 + 95 × 2) ÷ 8 = 703.5 ÷ 8 = 87.94%.

The same letters land on a B+ with the middle conversion and a B with the lowest one, because “lowest” assumes every grade sat at the bottom of its range. Use the middle when you don’t know the exact percents and the lowest when you want the safe floor. The 4.0 version of 3.26 sits between a B (3.0) and a B+ (3.3); it is a points average, not a percent, so don’t convert it back to a percent with a straight multiplication.

If you have the actual percents from the gradebook, enter those instead of letters, since any conversion is a guess. To check what a percent means on your school’s scale, use the letter grade to percentage chart, and to see how letter averages turn into a weighted and unweighted GPA, move to the GPA tools.

Median, range and 4.0 points: what the extra numbers tell you

The average answers “where am I overall?” The other boxes answer different questions.

• Median — the middle grade. If it sits well above the average, a few low grades are dragging you down; if it’s below, a few high grades are carrying you.
• Range — the gap between your lowest and highest grade. A 14-point range, like the example, is a fairly steady record. A 40-point range means your results swing a lot, and the average hides that.
• GPA points (4.0) — each grade turned into its letter, then into points (A− = 3.7, B+ = 3.3), and averaged with the same weights. For the example list that’s 3.27. It is a rough guide only: a real GPA uses final course grades and credits, not individual assignments.

Read together, these numbers tell you whether to work on consistency (wide range) or on one weak spot (median far from the average).

When an average is the wrong tool

An average of grades is not always your class grade. If your teacher uses weighted categories (tests 40%, homework 20%…), averaging all your scores together will give the wrong answer — use the grade calculator and enter the categories. If the class uses total points, add up points instead of averaging percents: a 9/10 quiz and a 70/100 test are 90% and 70%, but together they are 79/110 = 71.8%, not 80%.

For a GPA across classes, the averaging happens on the 4.0 scale with credits as the weights. The GPA calculator handles honors and AP bumps too.

Related tools

• Weighted categories or points from a syllabus: the grade calculator.
• Turn one test into a percent and letter: the test score calculator.
• Compare percent, letter and GPA on other scales: the grading scale converter.
• Teachers adjusting a whole class’s scores can use the grade curve calculator.