Number Sum Calculator

Add up a list of numbers and see the full statistical breakdown, live.

Sample Open file Clear
Sum
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Count
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Mean
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Median
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Mode
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Min
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Max
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Range
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Std. dev (σ)
Copy all results

About the Number Sum Calculator

What does this tool do?

At its simplest, it adds up a list of numbers and gives you the total. But it does more than that: paste a column from a spreadsheet, a line of comma-separated values, or a paragraph with numbers buried in it, and you instantly get the sum along with the count, mean, median, mode, smallest and largest values, the range, and the standard deviation. The numbers can be separated by anything — commas, spaces, tabs, new lines — and any words or symbols around them are simply ignored.

Everything recalculates the moment you type or paste, so there's no button to press. Click any result to copy it on its own, or grab the whole breakdown at once. It all runs in your browser, which means it's quick, it works offline, and the numbers you paste never leave your device — handy when you're totting up something you'd rather not upload.

How to Use This Tool

  1. Add your numbers. Paste or type them into the box, drop a .txt or .csv file onto it, or hit Sample to try it out. Separators don't matter.
  2. Read the results. The Sum is front and centre, with the count, mean, median, mode, min, max, range, and standard deviation in the grid beside it — all updating live.
  3. Adjust if needed. If your data uses commas as thousands separators (like 1,250), flip that switch so they're read as one number. Set a fixed number of decimal places for cleaner figures.
  4. Copy what you need. Click a single stat to copy just that value, or use Copy all results for the full summary.

Common Use Cases

It's the kind of small tool you end up using all the time:

  • Totalling figures from a spreadsheet: Copy a column of prices, hours, or scores and get the sum and average without writing a formula.
  • Checking an invoice or receipt: Paste the line items and confirm they add up to the total you expected.
  • Quick statistics for a dataset: Get the mean, median, and standard deviation of a sample in one shot for a report or homework.
  • Adding numbers out of messy text: Pull the totals out of an email or a chat log where the numbers are mixed in with words.
  • Tallying measurements or readings: Sum a list of weights, distances, or sensor readings and see the spread with the range and min/max.

Working with the numbers as text? Our Text Cleaner and Word Frequency Counter pair nicely with it.

Frequently Asked Questions

What kinds of numbers does it handle?

Positive and negative numbers, decimals, and scientific notation like 1.5e3 are all recognized. The tool scans your text, pulls out everything that looks like a number, and ignores the rest, so you can paste straight from a spreadsheet, a document, or a web page without cleaning it up first.

How does the "thousands separators" option work?

By default a comma is treated as a separator between numbers, so 1,250 would read as the two numbers 1 and 250. If your data uses commas to group digits (the usual way of writing one thousand two hundred fifty), turn the switch on and 1,250 is read as the single number 1250. Leave it off when commas are just dividing your values.

What's the difference between the mean, median, and mode?

The mean is the average — the sum divided by how many numbers there are. The median is the middle value once the numbers are sorted, which is less skewed by a few very large or very small entries. The mode is the value that appears most often (it shows "None" when nothing repeats). Together they describe the "centre" of your data from three useful angles.

Is the standard deviation population or sample?

It's the population standard deviation, meaning it divides by the number of values (n). It tells you how spread out your numbers are around the mean. If you specifically need the sample standard deviation (dividing by n−1), that figure will be slightly larger for the same data.

Can it handle a very long list?

Yes. It comfortably handles thousands of numbers because the maths runs locally in your browser. Extremely large pastes depend on your device's memory, but everyday lists and full spreadsheet columns are summed instantly.

Is my data private?

Completely. Every calculation happens in your browser with JavaScript. Nothing you paste is uploaded, stored, or logged, and the tool keeps working even if you go offline after the page has loaded.