Add UUID Column to Excel Files Online
Add a UUID column to Excel files directly in your browser. Generate random UUIDv4 or time-ordered UUIDv7 identifiers for every row. Choose the column name and position — no upload required.
How to add UUID Column to Excel files
- Drop your file onto the upload area. The first 200 rows are shown.
- Choose the UUID version: UUIDv4 (random, the default) or UUIDv7 (time-ordered to the millisecond).
- Set the column name, which defaults to "id", and the position: first column (prepend) or last column (append).
- Click Add UUID Column. Every row gets its own identifier.
- Download the file in the same format you uploaded. Keep that downloaded copy, because running the tool again produces different UUIDs.
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 research team is about to share survey responses with an outside analyst. Rows have no identifier, and the team needs one so both sides can refer to the same response in follow-up questions.
Input (Excel)
Excel workbook, first sheet (Sheet1)
| submitted_on | country | nps_score |
|---|---|---|
| 2026-08-02 | Ireland | 9 |
| 2026-08-02 | Canada | 6 |
| 2026-08-03 | Ireland | 10 |
| 2026-08-04 | Japan | 7 |
Settings
- UUID version: UUIDv4 (random)
- Column name: response_id
- Column position: First column (prepend)
Result
| response_id | submitted_on | country | nps_score |
|---|---|---|---|
| 3f9c2b1e-8a47-4d2c-9b6e-2c71d0a5e4f8 | 2026-08-02 | Ireland | 9 |
| b07e41d9-5c3a-4f86-a1d2-9e8f6b3c7a15 | 2026-08-02 | Canada | 6 |
| 6a2d8e5f-1b94-47c0-8e3a-f5d1c9b2a067 | 2026-08-03 | Ireland | 10 |
| d4c81f36-e2a9-4b75-b608-1a7e3f9d52cb | 2026-08-04 | Japan | 7 |
A new response_id column is added as the first column and the other columns are unchanged. The UUIDs shown are examples. They are random, so you get different values every time you run the tool. The 4 at the start of the third group marks them as version 4. No row order or content is used to create them.
Working with Excel files
Excel has no UUID type, so the identifier is stored as a text cell in Sheet1 of the downloaded workbook. Because the cells are stored as text, Excel displays them exactly as written and does not try to convert them. The column is wide, 36 characters, so widen it or it will look cut off on screen even though the full value is there. Other cells are written from the values as they loaded, so currency columns that arrived as displayed text come back as text cells. Dates load as real dates but are written as yyyy-mm-dd text cells, not Excel dates. Reapply number formats afterwards if you need them.
UUIDs are useful when a workbook is copied, sorted and filtered by several people. A row keeps its id no matter how it is moved, unlike a row number. Excel lookups work with them too: XLOOKUP and VLOOKUP match UUID text exactly, and they are case-insensitive, so upper and lowercase versions still match. Only the first sheet of your workbook is read, and other sheets are not carried into the output.
Frequently Asked Questions
Will Excel change the UUIDs when I open the file?
No. They are written as text cells, so Excel shows them as-is. Problems only arise if you copy them into cells already formatted as numbers.
Can I generate UUIDs with an Excel formula instead?
Excel has no built-in UUID function, and formula-based versions recalculate every time the sheet changes. Adding them with this tool gives fixed values that never change.
Are the UUIDs the same if I run the tool twice?
No. New values are generated on every run. Keep the downloaded file as the master copy. For ids that can be recreated from the data, use Hash & Anonymise Columns on a unique column instead.
What is the difference between UUIDv4 and UUIDv7?
UUIDv4 is random. UUIDv7 starts with a millisecond timestamp followed by random bits, so ids from a later run sort after ids from an earlier one. Rows generated in the same millisecond are in random order, so a whole file processed in one run is not sorted by its UUIDv7 column. Use Add Row Numbers if you need to keep the original order.
Can two rows get the same UUID?
In practice, no. A UUIDv4 has 122 random bits, so the chance of a repeat in a file of millions of rows is far too small to matter.
Related Tools
Manage Columns in Excel Files Online
Drop or select specific columns from Excel files directly in your browser. No upload required.
Hash & Anonymise Columns in Excel Files Online
Anonymise or pseudonymise columns in Excel files by replacing values with MD5, SHA-256, or DuckDB hashes — directly in your browser. Useful for GDPR compliance and sharing data without exposing PII — no upload required.
Split Excel Files Online
Split Excel files into multiple smaller files by row count, directly in your browser.
Add UUID Column to CSV Files Online
Add a UUID column to CSV files directly in your browser. Generate random UUIDv4 or time-ordered UUIDv7 identifiers for every row. Choose the column name and position — no upload required.
Add UUID Column to Parquet Files Online
Add a UUID column to Parquet files directly in your browser. Generate random UUIDv4 or time-ordered UUIDv7 identifiers for every row. Choose the column name and position — no upload required.
Add UUID Column to JSON Files Online
Add a UUID column to JSON files directly in your browser. Generate random UUIDv4 or time-ordered UUIDv7 identifiers for every row. Choose the column name and position — no upload required.
Excel Viewer Online
View and inspect Excel files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.
Convert Excel to Parquet Online
Convert Excel files to Parquet format directly in your browser. No upload required — your data never leaves your device.