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Weighted Average Calculator
A weighted average lets some values count for more than others. Enter your values and a matching list of weights — percentages, credit hours, quantities — and the calculator returns the weighted mean alongside the ordinary unweighted one.
- Sum of weights
- 100
- Sum of value × weight
- 8,300
- Unweighted average
- 80
Saved setups
Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.
Your recent calculations
Results you calculate here are kept on this device so you can come back to them.
Formula
How to use it
- Type the values, separated by commas.
- Type one weight for each value, in the same order.
- Read the weighted average. The weights do not need to add up to 100 or to 1.
Worked examples
Scores of 90, 80 and 70 weighted 50%, 30% and 20%
- Weighted average
- 83
- Sum of weights
- 100
- Sum of value × weight
- 8,300
- Unweighted average
- 80
Grade points 4.0, 3.0, 3.7 and 2.0 for 3, 4, 3 and 2 credits
- Weighted average
- 3.2583
- Sum of weights
- 12
- Sum of value × weight
- 39.1
Worked examples
Course grade: scores of 90, 80 and 70 weighted 50%, 30% and 20% give (90 × 50 + 80 × 30 + 70 × 20) ÷ 100 = 8,300 ÷ 100 = 83.
GPA: grade points of 4.0, 3.0, 3.7 and 2.0 for courses worth 3, 4, 3 and 2 credits give 39.1 ÷ 12 = 3.26.
Average price paid: buying 100 shares at $10.50, 50 at $12.00 and 200 at $9.75 costs $3,600 for 350 shares, an average of $10.29.
The mistake it prevents
Averaging averages without weights gives the wrong answer whenever the groups differ in size. A class of 10 averaging 90 and a class of 30 averaging 70 have a combined average of 75, not 80.
Questions people ask
What is the weighted average of 90, 80 and 70 with weights 50%, 30% and 20%?
83. The plain average of the three scores is 80; the heavier weight on the 90 pulls it up.
Do the weights have to add up to 100?
No. The formula divides by the total weight, so 5, 3, 2 gives the same answer as 50, 30, 20.
How is a GPA a weighted average?
Each grade’s points are weighted by the course’s credit hours. Multiply points by credits, add them up, and divide by total credits.