Math
Average Calculator
Paste or type your numbers, separated by spaces, commas or line breaks.
The formula
mean = sum ÷ count
median = the middle value once sorted
range = largest − smallest
Worked example
The list 2, 4, 4, 5, 10
- sum = 25 and count = 5
- mean = 25 ÷ 5 = 5
- sorted: 2 4 4 5 10, so the median is 4
Where this goes wrong
Using the mean when the median tells the truth
Nine people earning $30,000 and one earning $500,000 have a mean salary of $77,000 — a figure nobody in the room earns. One extreme value drags the mean towards itself and leaves the median untouched. When the spread is lopsided, the median is the honest summary.
Questions
- Should I use the mean or the median?
- Use the median when a few extreme values would distort the picture — incomes, house prices, response times. For 1, 2, 3, 4, 1000 the mean is 202 while the median is 3, and only one of those describes a typical value.
- What is the median of an even number of values?
- The average of the two middle values once the list is sorted. For 1, 2, 3, 4 the median is 2.5, even though no value in the list equals it.
- Can I paste a column from a spreadsheet?
- Yes. Line breaks, spaces, commas and semicolons all count as separators, and anything that is not a number is ignored rather than breaking the calculation.