Average Calculator

This calculator reports two different measures of the “center” of your data — the average (mean) and the median — because they answer slightly different questions and can diverge sharply on real-world data.

• Sum: add up every number in the list.
• Average (Mean): Sum ÷ Count — every value pulls the result toward it, so one very large or very small number can shift the mean a lot.
• Median: sort the numbers and take the middle value. For an even count, average the two middle values. The median ignores how far outliers are from the rest of the data — it only cares about their position.

Mean vs. median — when to use which:the mean is the right choice for data that's roughly evenly spread, like test scores or measurements. The median is more useful when a few extreme values would otherwise distort the picture — the classic example is salaries at a company: one executive earning several times more than everyone else can drag the average salary well above what a typical employee actually earns, while the median salary stays close to what most people are paid.

Worked example: for the numbers 4, 8, 15, 16, 23, the count is 5, the sum is 66, the average is 66 ÷ 5 = 13.2, and since the count is odd, the median is simply the middle value once sorted (4, 8, 15, 16, 23) — 15. If you add one more number, say 42, making the list 4, 8, 15, 16, 23, 42, the count becomes 6 (even), so the median is the average of the two middle values, 15 and 16, giving 15.5.

Handling invalid input: the tool splits your text on commas, spaces, and line breaks, then keeps only the tokens that parse as valid numbers — words, stray punctuation, or empty entries are silently dropped rather than causing an error, so you can paste data straight from a spreadsheet or document without pre-cleaning it.