Add Cumulative Sum to TSV Files Online
Add a running total column to TSV files for any numeric column. Optionally order by a date or sequence column and restart totals per group — no upload required.
How to add Cumulative Sum to TSV files
- Drop your file onto the upload area. It is loaded into the in-browser engine and the first 200 rows are shown.
- Choose the value column to sum. Only numeric columns are listed, and the first one is preselected.
- Choose an Order by column, usually a date or sequence number. Leave it at (none) to add up rows in file order, top to bottom.
- Optionally choose a Partition by column so the running total restarts for each group. Rename the output column from cumulative_sum if you like, then click Add Cumulative Sum.
- Check the preview and download the file in the same format you uploaded.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
A facilities team logs daily solar generation in kWh for two roof arrays. They want month-to-date output for each array, so the running total must restart per site.
Input (TSV)
reading_date site kwh
2026-06-01 Roof A 18.5
2026-06-01 Roof B 11
2026-06-02 Roof A 21
2026-06-02 Roof B 9.5
2026-06-03 Roof A 16.5
2026-06-03 Roof B 12.5Settings
- Value column: kwh
- Order by: reading_date
- Partition by: site
- Output column name: cumulative_sum
Result
| reading_date | site | kwh | cumulative_sum |
|---|---|---|---|
| 2026-06-01 | Roof A | 18.5 | 18.5 |
| 2026-06-01 | Roof B | 11 | 11 |
| 2026-06-02 | Roof A | 21 | 39.5 |
| 2026-06-02 | Roof B | 9.5 | 20.5 |
| 2026-06-03 | Roof A | 16.5 | 56 |
| 2026-06-03 | Roof B | 12.5 | 33 |
Each site gets its own running total in date order: Roof A goes 18.5, 39.5, 56 and Roof B goes 11, 20.5, 33. The rows stay in their original order. With Order by and Partition by both left at (none), the total would run down the file instead: 18.5, 29.5, 50.5, 60, 76.5 and 89.
Frequently Asked Questions
What does (none) in Order by do?
It adds up rows in file order, top to bottom. With a Partition by column, each group has its own running total, still in file order. Pick a date or sequence column when the file is not already sorted.
How does the total restart for each group?
Choose a Partition by column. The total starts again at the first row of each group value, in Order by order or in file order when Order by is (none). Rows are not regrouped, so they keep their original order.
How are rows with the same Order by value handled?
They are added in file order, one row at a time. The result is the same every time you run it.
Related Tools
Add Percent of Total to CSV Files Online
Add a percentage-of-total column to CSV files directly in your browser. Show each row's share of the grand total, or the share within each group — no upload required.
Add Moving Average to CSV Files Online
Add a moving average, rolling sum, rolling min, or rolling max column to CSV files directly in your browser. Choose window size, order-by column, and optional partitioning — no upload required.
Add Lag / Lead Column to CSV Files Online
Add a LAG or LEAD column to CSV files to shift any column forward or backward by N rows. See previous day's sales, next value in a sequence, or any time-shifted comparison — runs entirely in your browser.
Add Cumulative Sum to CSV Files Online
Add a running total column to CSV files for any numeric column. Optionally order by a date or sequence column and restart totals per group — no upload required.
Add Cumulative Sum to Excel Files Online
Add a running total column to Excel files for any numeric column. Optionally order by a date or sequence column and restart totals per group — no upload required.
Add Cumulative Sum to Parquet Files Online
Add a running total column to Parquet files for any numeric column. Optionally order by a date or sequence column and restart totals per group — no upload required.
Add Cumulative Sum to JSON Files Online
Add a running total column to JSON files for any numeric column. Optionally order by a date or sequence column and restart totals per group — no upload required.
TSV Viewer Online
View and inspect TSV files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.