SmartQueryTools

Find & Replace in CSV Files Online

Find and replace text values in CSV files directly in your browser. Supports plain text and regex patterns across any column — no upload required.

How to find & Replace in CSV files

  1. Drop your file onto the upload area. The tool shows the row count, how many text columns it found, and the first 200 rows.
  2. In Apply to column, keep All text columns or pick one column. Number, date and boolean columns are never changed.
  3. Type the text to find and the replacement. Leave Replace with empty to delete every match.
  4. Tick Use regular expression if the Find box holds a pattern rather than literal text, then click Find & Replace.
  5. Check the result preview and download the file in the same format.

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 contractor list was typed in by hand, so phone numbers mix brackets, spaces, dashes and a country prefix. The SMS gateway wants digits only.

Input (CSV)

name,phone,city
Aroha Ngata,(021) 555-0143,Auckland
Liam Park,021 555 0198,Hamilton
Mele Tupou,+64 21 555 0112,Auckland
Sam Reid,,Tauranga

Settings

  • Apply to column: phone
  • Find: [^0-9]
  • Replace with: (empty)
  • Use regular expression: ticked

Result

namephonecity
Aroha Ngata0215550143Auckland
Liam Park0215550198Hamilton
Mele Tupou64215550112Auckland
Sam ReidNULLTauranga

The pattern [^0-9] matches any character that is not a digit, and every match in the cell is replaced, not just the first. Brackets, spaces, dashes and the plus sign are removed. The phone column stays text, so the leading zero survives. Sam's empty phone stays empty. Limiting the run to the phone column keeps the other columns untouched.

Working with CSV files

Only columns typed as text are searched, and in a CSV the type comes from the values on load. A postcode or ID column holding only digits is typed as a number and does not appear in the column list, even though it looks like text in the file. If you need to replace inside such a column, convert it to text with Cast Columns first. Plain matching is case-sensitive, so "st." and "St." are different searches.

Watch the output when you remove characters from a text column. The cleaned values are written out as text, but the next tool that opens the CSV will infer types again. A column cleaned down to digits, like the phone numbers above, can be re-read as a number and lose its leading zeros. Values that contain a comma, quote or line break after replacement are wrapped in double quotes in the downloaded CSV, so the file still parses.

Frequently Asked Questions

Why is a CSV column missing from the Apply to column list?

The list only shows text columns. A column with only numbers or dates in the CSV is typed as a number or date on load and is excluded. Cast it to text first if you need to edit it.

Can I remove the thousands separators from a CSV number column?

Yes, if the column loaded as text because of the commas. Find , with an empty replacement, then use Cast Columns to turn the result into a number.

Is the search case-sensitive?

Yes, in both modes. With Use regular expression ticked, you can start the pattern with (?i) to ignore case, for example (?i)limited.

Can I use capture groups in the replacement?

Yes. In regex mode, write \1, \2 and so on in Replace with. For example, find (\d{4})-(\d{2}) and replace with \2/\1 to turn 2026-04 into 04/2026. The syntax is RE2, so lookaheads and lookbehinds are not supported.

Does it replace every match or only the first one in each cell?

Every match. Both plain text and regex mode replace all occurrences in each cell of the targeted columns.

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