Average Calculator — Free Online Tool
Paste any list of numbers to get the arithmetic mean instantly — with the sum, the count of valid values, and any invalid entries flagged.
Meanarithmetic average
your average will appear here
—
Sum
—
Valid numbers
Live calculation
No sign-up needed
Free forever
How it works
1Paste or type your numbers — separate them with commas, spaces or newlines.
2Press Calculate (or just keep typing — it updates live).
3Check the details — mean, sum, count, and any entries that were skipped.
Frequently asked questions
How is the average calculated?
It is the arithmetic mean: all valid numbers are added together and the total is divided by how many valid numbers there are. For example, the average of 12, 45 and 78 is (12 + 45 + 78) ÷ 3 = 45.
What happens to entries that are not numbers?
Anything that is not a valid number (like "abc" or "12x") is ignored in the calculation and listed under "Ignored entries" so you can spot typos in your pasted data.
Can I mix commas, spaces and line breaks?
Yes — commas, spaces, semicolons, tabs and newlines all work as separators, and you can mix them freely. Empty gaps are skipped automatically.
Arithmetic mean · Sum & count · Invalid entries flagged · 100% local — your data never leaves this page.