Weighted Grade Calculator
This weighted grade calculator averages individual scores that carry different importance — for example, when one assignment counts double or a lab report is worth triple a quiz. Enter up to three scores with a weight for each, and the calculator normalizes the weights automatically. It is the general-purpose version of a weighted mean: use it for grades, peer-review scores, or any rating where some inputs deserve more influence than others.
First score, as a percent.
Relative importance — e.g. 2 means "counts double".
Second score, as a percent.
Relative importance — e.g. 2 means "counts double".
Third score, as a percent.
Relative importance — e.g. 3 means "counts triple".
Weighted average — B
83.17%
- Weighted average
- 83.17%
- Score 1 contribution85% × weight 1 ÷ total weight 6.
- 14.17%
- Score 2 contribution90% × weight 2 ÷ total weight 6.
- 30%
- Score 3 contribution78% × weight 3 ÷ total weight 6.
- 39%
How it was calculated
- Total weight: 1 + 2 + 3 = 6.
- Score 1: 85% × 1 ÷ 6 = 14.17 pts.
- Score 2: 90% × 2 ÷ 6 = 30.00 pts.
- Score 3: 78% × 3 ÷ 6 = 39.00 pts.
- Weighted average: 14.17 + 30.00 + 39.00 = 83.17% (B).
How it works
A weighted average multiplies each score by its weight, adds those products, and divides by the sum of the weights: (s₁×w₁ + s₂×w₂ + s₃×w₃) ÷ (w₁ + w₂ + w₃).
Weights are relative, not percentages — weights of 1, 2, 3 give exactly the same answer as 10, 20, 30 or 25%, 50%, 75%, because only the ratios matter.
Setting a weight to 0 excludes that score entirely, which is useful for "what-if" checks like dropping an assignment.
The letter grade uses the standard US scale: A for 90% and up, B for 80–89%, C for 70–79%, D for 60–69%, F below 60%.
Worked examples
Lab counts triple, quiz double
Scores 85 (weight 1), 90 (weight 2), 78 (weight 3): (85 + 180 + 234) ÷ 6 = 83.17%, a B. The low lab score drags the average down because it carries half the total weight.
One assignment counts double
Scores 100 (weight 2) and 50 (weight 1): (200 + 50) ÷ 3 = 83.33%. A plain average would say 75% — the weight on the strong score lifts the result by more than 8 points.
How to measure
- Translate syllabus language into weights: "counts double" = weight 2, "worth 30%" = weight 30 — the ratios are what matter.
- Keep every score on the same scale (all percents) before weighting; do not mix raw points with percents.
- Use weight 0 to test scenarios, such as "what if the professor drops my lowest quiz".
- If weights are given as percents that sum to 100, you can enter them directly — the normalization handles it.
- Round weights to whole numbers; tiny fractional differences in weight barely move the result.
Assumptions & limitations
Planning estimate
- All scores are assumed to be on the same 0–100 scale; mixing scales (e.g. a 50-point quiz with percent exams) requires converting to percents first.
- Weights are treated as relative multipliers — only their ratios affect the answer, so "1, 2, 3" and "10, 20, 30" are identical.
- The standard US letter scale is applied (A 90+, B 80+, C 70+, D 60+, F below 60); your course may use different cutoffs.
- No curving or dropped scores are applied — adjust the inputs yourself if your course drops the lowest item.
Frequently asked questions
Multiply each score by its weight, add the results, and divide by the sum of the weights. With scores of 85, 90, and 78 weighted 1, 2, and 3, that is (85 + 180 + 234) ÷ 6 = 83.17%. The weights need not sum to 100 — only their ratios matter.
A regular average treats every score equally; a weighted average lets important scores pull harder. In the example above the plain average is 84.33%, but weighting the lowest score triple drops the result to 83.17%. The gap grows as weights get more lopsided.
No. This calculator normalizes automatically, so 1-2-3 works exactly like 10-20-30 or 16.7%-33.3%-50%. Use whatever numbers are convenient; the ratios are the only thing that counts.
Yes — the math is the general weighted mean. It works for product ratings with different reviewer weights, investment blends, or any average where inputs deserve unequal influence, as long as all scores share one scale.
Because weight amplifies influence in both directions. A 78 with weight 3 contributes as much as three 78s at weight 1. High-weight items dominate the average, which is exactly what the syllabus intends.