Quiz Score Percentage Calculator (Formula + Examples)

TL;DR. Quiz percentage = (points earned / points possible) × 100. This page gives the formula, worked examples for the common variations (weighted, extra credit, dropping low scores), and pointers to SimpleQuizMaker's built-in auto-scoring.

The basic formula

Quiz percentage = (Points earned ÷ Points possible) × 100

Examples:

Letter grade conversion (US standard)

| Percentage | Letter |

|---|---|

| 90–100% | A |

| 80–89% | B |

| 70–79% | C |

| 60–69% | D |

| Below 60% | F |

With +/− modifiers:

Per-question weighting

If your questions are worth different points (e.g., 5 questions × 2 pts + 5 questions × 4 pts):

Total possible = (5 × 2) + (5 × 4) = 30

If a student got 4 of the 2-point questions and 3 of the 4-point questions:

Weighted average across multiple quizzes

If 4 quizzes have different weights:

Weighted avg = (Q1 × W1 + Q2 × W2 + Q3 × W3 + Q4 × W4) ÷ (W1 + W2 + W3 + W4)

Example: 80% (W=1), 85% (W=1), 90% (W=2), 75% (W=1):

= (80 + 85 + 180 + 75) ÷ 5 = 420 ÷ 5 = 84%

Dropping the lowest score

A common student-friendly policy:

Example: scores 60, 70, 80, 90, 100. Mean = 80. Without the 60: mean = 85. Final = 85%.

Extra credit

Most common approach: add to numerator only, cap at 100%.

Example: earned 17 + 2 extra credit = 19, possible stays at 20. Percentage = 95%.

Alternative (less generous): add to both. Earned 19, possible 22. Percentage = 86%.

Curving a quiz

If a quiz turned out too hard, add a constant to every score.

Example: highest score in class is 78. Add 22 to everyone — the top becomes 100, everyone else scales up.

Excel formula

```

Percentage cell: =ROUND(POINTS_EARNED / POINTS_POSSIBLE * 100, 2)

Letter cell: =IF(P>=90,"A",IF(P>=80,"B",IF(P>=70,"C",IF(P>=60,"D","F"))))

```

For weighted average:

```

=SUMPRODUCT(scores, weights) / SUM(weights)

```

Auto-scoring in SimpleQuizMaker

SimpleQuizMaker computes percentage and letter grade automatically. Configure your school's grading scale and weighting in settings; the dashboard shows scores per student per quiz, plus class averages and per-question item statistics.

You never have to open a spreadsheet for quiz grading again.

Related reading

Auto-grade your next quiz →