Formulas
Arithmetic Mean
Average = Sum of Numbers ÷ Count
Weighted Average
WA = Σ(value × weight) ÷ Σ(weight)
Missing Number from Average
Missing = (New Average × New Count) − Old Sum
How to Use
1
Enter Numbers
Type or paste your numbers separated by commas, spaces, or new lines.
2
Click Calculate
Hit Calculate to get the average along with sum, count, min, max and range.
3
Weighted Mode
Use the Weighted Average tab when each value has a different importance or weight.
Frequently Asked Questions
Average = Sum of all values ÷ Number of values. For example, average of 10, 20, 30 = (10+20+30) ÷ 3 = 20.
Old sum = 5 × 20 = 100. New sum = 6 × 25 = 150. 6th number = 150 − 100 = 50.
A weighted average gives different importance (weight) to different values. Formula: WA = Σ(value × weight) ÷ Σ(weight). Used in mixture, alligation, and result calculation problems.