Last updated: October 2026
What is a weighted average?
Short answer: multiply each score by its weight, add those products up, and divide by the total weight. In grading, a final exam worth 50% pulls your average far more than a quiz worth 5% — a simple average would treat them equally. Enter your scores and weights above and the calculator does it live.
How to calculate weighted average
Short answer: list each score with its weight, multiply score × weight for each row, add up those products, then divide by the total weight. Four steps: (1) write down every score and its weight, (2) multiply each score by its weight, (3) add up all the products, (4) divide by the sum of the weights. The calculator above runs the same four steps instantly as you type.
- List scores and weights. Example: homework 92 (weight 20), quizzes 85 (weight 30), final 78 (weight 50).
- Multiply each score by its weight. 92 × 20 = 1840; 85 × 30 = 2550; 78 × 50 = 3900.
- Add the products. 1840 + 2550 + 3900 = 8290.
- Divide by the total weight. 8290 ÷ 100 = 82.9%.
How to average weighted grades by hand
Paper and pencil follow the same four steps — the 82.9% in the worked example above was computed exactly this way. Two tips that prevent most mistakes: convert every weight to the same units first (all percentages — never a mix of 0.2 and 20), and if your weights don't total 100, divide by the actual total instead of 100.
Weighted average formula — worked example
The formula never changes, only the numbers:
avg = (score1 × weight1 + score2 × weight2 + …) ÷ (weight1 + weight2 + …)
Say your class breaks down as homework 92 at 20%, quizzes 85 at 30%, and final 78 at 50%. The math: (92 × 20 + 85 × 30 + 78 × 50) ÷ 100 = 82.9%. Notice the final drags the average down toward 78 despite the strong homework — that's weighting doing its job. If scores have different maximums (say 45 out of 50), convert each to a percentage first; the calculator's "/max" field handles that automatically.
What grade do I need on the final?
Flip the formula around. If your current average is 84%, the final is worth 25%, and you want a 90% overall: needed = (90 − 84 × 0.75) ÷ 0.25 = 108% — impossible, even with a perfect final. That honest answer is the point: the "Final Grade Needed" mode tells you the exact required score, warns you when the target is unreachable, and confirms when you've already secured it.
Weights that don't add to 100%
The math still works — the calculator divides by your actual total weight, not by 100. But a total like 60% usually means a typo (writing 0.2 instead of 20 for a 20% weight is the classic one). Whenever your weights don't total 100%, the tool shows a warning so you can double-check before trusting the number.
Letter grade scale
This is the standard US 10-point scale the calculator uses. Some schools use plus/minus or different cutoffs — the percentage is what matters; map it to your school's scale. Combining several courses into one number? A GPA is the same weighted-average idea — each course's grade points (0–4 scale) weighted by its credit hours. Enter grade points as scores and credit hours as weights above to approximate it; ToolVaultly doesn't have a dedicated GPA calculator yet.
A high weighted average can hide a failing grade
A strong average feels safe, but weights cut both ways: perfect homework can mask a failing exam that carries half the weight. Always check the individual scores behind the average — especially the highest-weighted one. If you're one exam away from the semester, run your numbers through the final grade calculator to see exactly what you need, and the percentage increase calculator shows how far each score has to climb. The math itself is the weighted arithmetic mean.
Frequently asked questions
What is a weighted average?
A weighted average gives some values more influence than others. Multiply each score by its weight, add those products up, and divide by the total weight. In grading, a final exam worth 50% pulls your average far more than a quiz worth 5% — a simple average would treat them equally, which is unfair to the final.
How is a weighted average different from a simple average?
A simple average divides every value's contribution equally: (a + b + c) ÷ 3. A weighted average multiplies each value by its importance first: (a×w1 + b×w2 + c×w3) ÷ (w1 + w2 + w3). Use a simple average when every item counts the same; use a weighted average whenever some items matter more — grades, GPA, investment returns, survey scores.
What if my weights don't add up to 100?
The math still works: the calculator divides by your actual total weight, not by 100. But if you meant weights to total 100%, something is off — a common mistake is typing 0.2 instead of 20 for a 20% weight. The calculator warns you whenever the total isn't 100% so you can check.
How do I calculate what I need on my final exam?
Use the formula: needed = (target − current × (1 − final weight)) ÷ final weight, with the weight as a decimal. Example: your current average is 84%, the final is worth 25%, and you want 90% — needed = (90 − 84 × 0.75) ÷ 0.25 = 108%, which is impossible, so you'd know to adjust your target. The calculator's "Final Grade Needed" mode does this instantly and tells you if the target is unreachable.
What is the formula for weighted average?
Weighted average = (score1 × weight1 + score2 × weight2 + …) ÷ (weight1 + weight2 + …). Example: homework 92 at 20%, quizzes 85 at 30%, final 78 at 50% → (92×20 + 85×30 + 78×50) ÷ 100 = 82.9%. If your scores have different maximums (say 45 out of 50), convert each to a percentage first — the calculator does that automatically from the "/max" field.
Can a weighted average be higher than my highest score?
No. A weighted average always falls between your lowest and highest score — weights only shift it toward the scores that matter most. If your calculator shows something outside that range, check for a typo (a weight of 2 instead of 20, or a score above its maximum).
What is a weighted average grade calculator?
A tool that computes your course grade from assignment scores and their weights — homework, quizzes, exams — instead of treating every score equally. The calculator at the top of this page is one: add a row per assignment, enter each score and weight, and your weighted average, letter grade, and final-exam target update live.
How do I calculate weighted average in Excel?
Put scores in one column and weights in the next, then use =SUMPRODUCT(A2:A10,B2:B10)/SUM(B2:B10) — SUMPRODUCT multiplies each score by its weight and adds them up, and dividing by the weight total finishes the formula. If you landed here searching for a "weighted average calculator excel" solution, that formula is the spreadsheet answer — or skip Excel entirely and enter the same numbers in the calculator at the top of this page.
What is a weighted average cost of capital calculator?
WACC blends what a company pays for its funding: (equity ÷ total × cost of equity) + (debt ÷ total × cost of debt × (1 − tax rate)). It is a weighted average where the weights are each funding source's share of total capital. This page's calculator can do the weighting step — enter each cost as a score and its share as the weight — but it is not a dedicated WACC tool: it won't look up tax rates or market values for you.
Is my data private?
Completely. Every calculation happens locally in your browser with JavaScript — your grades are never sent to a server, stored, or tracked in any way.
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