Cumulative Sum Calculator
Get the running total of a list of numbers, row by row — with optional running average, minimum, and maximum. Paste comma, space, or newline-separated values. Runs entirely in your browser — no server, no sign-up.
What this tool does
The Cumulative Sum Calculator produces the running total — the prefix sum — of a list of numbers, right in your browser. Paste your numbers, and get back a table with one row per value: the value itself and the cumulative sum up to that point. Nothing is sent to a server — it runs locally, works offline, and needs no sign-up.
It is the quick way to turn a column of numbers into a running balance or a
step-by-step accumulation, the way a spreadsheet does with a =SUM($A$1:A1)
fill-down formula — without opening a spreadsheet.
How it works
- Paste your list of numbers into Numbers (one per line, or separated by commas or spaces).
- Optionally tick Running average, Running minimum, and/or Running maximum to add those columns.
- Read the result — one row per input value, columns separated by
|.
Columns
| Column | What it shows (at each row) |
|---|---|
| value | the input number for that row |
| cumulative_sum | the running total of every value up to and including this one |
| running_avg (optional) | the average (mean) of the values seen so far |
| running_min (optional) | the smallest value seen so far |
| running_max (optional) | the largest value seen so far |
Input format
- Values may be separated by commas, spaces, or newlines — or any mix of them.
- Blank lines and trailing separators are ignored, so a trailing comma or an empty last line is fine.
- Decimals and negative numbers are supported. Whole-number results print without
a trailing
.0(so2 + 2shows as4, not4.0).
Examples
A plain running total of 1, 2, 3, 4:
value | cumulative_sum
1 | 1
2 | 3
3 | 6
4 | 10
With the running average, minimum, and maximum turned on for 3, 1, 4, 1, 5:
value | cumulative_sum | running_avg | running_min | running_max
3 | 3 | 3 | 3 | 3
1 | 4 | 2 | 1 | 3
4 | 8 | 2.6666666667 | 1 | 4
1 | 9 | 2.25 | 1 | 4
5 | 14 | 2.8 | 1 | 5
FAQ
What is a cumulative sum?
It is the running total: each entry is the sum of all the values up to and including that position. The last value of the cumulative sum equals the grand total of the whole list.
Is it free and private?
Yes — your numbers never leave your device, and the tool keeps working offline once the page has loaded.
Can I paste a column straight from a spreadsheet?
Yes — a spreadsheet column copies as one value per line, which is exactly the format this tool accepts.
Does it handle decimals and negatives?
Yes. Mix integers, decimals, and negative numbers freely. Negative values simply make the running total go down.
What's the difference between the running average and a plain average?
The running average at each row is the mean of just the values seen so far, so it changes row by row; the plain average is a single number for the whole list (the running average on the final row).
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool cumulative-sum "1
2
3
4"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/cumulative-sum/?numbers=1%0A2%0A3%0A4&average=true&min=true&max=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.