Weighted Average Calculator for Marks, Grades and More
Write one item per line with its value and weight, like "Final exam 78 40". The weighted average updates as you type.
- Nothing you type is stored
- Free
- No signup
Weighted average
74.1
- Total weight
- 100
- Simple average
- 76.25
- Items counted
- 4
The weights add up to 100, so each weight is a percentage.
Show working
- Σ(w × x) = 7410
- Σw = 100
- 7410 ÷ 100 = 74.10
Item-wise
| Item | Value | Weight | Value × weight |
|---|---|---|---|
| Unit tests | 72 | 20 | 1,440 |
| Mid-term | 65 | 30 | 1,950 |
| Assignments | 90 | 10 | 900 |
| Final exam | 78 | 40 | 3,120 |
How to use
- Write one item per line: name (optional), value, weight.
- Weights can be percentages, credits or quantities.
- Read the weighted average and open the working.
Good to know
Weighted average = Σ(value × weight) ÷ Σ(weight). Unit tests 72 (20%), mid-term 65 (30%), assignments 90 (10%) and final 78 (40%) give (1440 + 1950 + 900 + 3120) ÷ 100 = 74.1.
Weights do not have to add up to 100; they are divided by their total. Use credits for GPA-style averages, quantities for an average purchase price, or percentages for internal assessment.
The simple average (all items equal) is shown for comparison. If one item has a much bigger weight, the weighted average moves towards it.
Questions
How do I calculate a weighted average?
Multiply each value by its weight, add the results, and divide by the sum of the weights.
Do the weights need to total 100?
No. Any positive weights work; the calculator divides by their total.
What is the difference between weighted and simple average?
A simple average treats every item equally. A weighted average gives more say to items with bigger weights, like a final exam worth 40%.
Can I use it for average share price?
Yes. Enter each price with the quantity bought as the weight to get the average buying price (before charges).
Is my data stored?
No. Everything is calculated on your device and nothing is sent anywhere.