Average Calculator

Find the mean of any list of numbers.

How it is calculated

The tool computes the arithmetic mean: mean = (x₁ + x₂ + … + xₙ) / n, where each x is a value in your list and n is how many values there are. It also reports n (the count) and the sum. You can separate the numbers with commas, semicolons, spaces or new lines, in any mix. Any entry that is not a valid number is silently ignored and not counted, so check that the count matches what you expected. Negative numbers and decimals written with a dot are accepted. If no valid number is found, no result is shown. The mean is pulled by extreme values; the median or mode may describe a typical value better when the list has outliers. Results are rounded to two decimals.

Worked example

A student has five exam scores: 72, 85, 90, 64 and 89. Adding them gives 72 + 85 = 157, then 157 + 90 = 247, then 247 + 64 = 311, then 311 + 89 = 400. The sum is 400.00 and the count is 5. The mean is 400 / 5 = 80.00. Notice that the scores 64 and 90 lie on opposite sides of this average, which is exactly what the mean balances.

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Common mistakes

  • Typing a decimal comma such as 7,5. The comma is a separator here, so this is read as two values, 7 and 5. Use a dot (7.5).
  • Not checking the count after pasting a list; text such as "n/a" or units glued to a number ("85kg") are skipped, so n comes out smaller than expected.
  • Averaging averages. If groups have different sizes, the mean of group means is not the overall mean; enter the raw values instead.
  • Using the mean for skewed data such as salaries or prices, where one very large value drags it far above the typical case.

About this calculator

This calculator finds the arithmetic mean of a list of numbers — add every value together, then divide by how many values there are. Alongside the mean it also reports the count and the sum, since those two numbers are what the average is actually built from.

Teachers use it to average grades, sports fans use it for batting averages or points per game, and anyone working with a spreadsheet uses it to sanity-check a quick set of figures without opening Excel. It accepts any list of numbers separated by commas, spaces or new lines, so pasted data works as-is.

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