CSV Cleaner
Tidy a messy CSV in one pass — trim cells, drop duplicates and empty rows, fill blanks, and normalize the delimiter + line endings. Runs entirely in your browser, nothing is uploaded.
Clean a messy CSV in one pass
Paste a CSV and this tool tidies it locally in your browser — nothing is uploaded. Every cleaning step is an independent toggle, so you can run just the ones you need:
- Trim whitespace — strip leading/trailing spaces from every cell.
- Remove duplicate rows — drop rows identical to an earlier one (the first is kept).
- Drop empty rows — remove rows whose every cell is blank.
- Fill empty cells — replace blank cells with a value like
N/Aor0. - Normalize the delimiter — re-emit with a comma, tab, semicolon, pipe, or any single character.
- Normalize line endings — output LF (
\n) or CRLF (\r\n, for Windows/Excel).
A first-row header is kept and exempted from dedup, empty-row drop, and cell fill, so your column names stay intact.
Worked example
With trim, remove duplicate rows, and drop empty rows all on, this input:
name , age
Alice ,30
Bob,25
,,
Bob,25
Carol, 40
becomes:
name,age
Alice,30
Bob,25
Carol,40
The spaces around name, Alice, 40, etc. are trimmed, the all-empty ,, row
is dropped, and the repeated Bob,25 row is removed — the header row stays.
FAQ
Which duplicate row is kept?
The first occurrence in the file; later identical rows are dropped. Duplicate
matching happens after trimming and filling, so Bob and Bob count as the
same row when trim is on.
Is the cleaning case-sensitive?
Yes. Cells are compared exactly, so Alice and alice are treated as different
values and won't be deduped together. The tool doesn't change letter case — it only
trims surrounding whitespace when you enable Trim.
What counts as an "empty row" or "empty cell"?
A cell is empty when it's blank or only whitespace. An empty row is a row where
every cell is empty (for example a stray ,,, line). Enable Drop fully-empty
rows to remove them, or Fill to replace individual empty cells with a value.
Can I change the delimiter, or read a tab/semicolon file?
Yes. Set the input delimiter to match your file (a single character, or
comma/tab/semicolon/pipe) and pick an output delimiter to re-emit with.
Leave the output on Same as input to keep the original separator.
Is my data uploaded anywhere?
No. The whole clean runs locally with WebAssembly; your CSV never leaves your browser.
Limits & edge cases
- Rows may have different column counts — cleaning is per-row and never pads to a fixed width. Missing trailing cells are treated as empty.
- Quoted fields are parsed as CSV, so a value like
"a, b"stays one cell and is re-quoted only when the output needs it. - Turn off First row is a header for files with no header row; then row 1 also participates in dedup, empty-row drop, and fill.
- Everything is processed in memory, so extremely large files are bounded by your browser's available memory.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool csv-cleaner "name , age
Alice ,30
Bob,25
,,
Bob,25"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/csv-cleaner/?data=name%20%2C%20age%0A%20Alice%20%2C30%0ABob%2C25%0A%2C%2C%0ABob%2C25&header=true&delimiter=%2C&output_delimiter=same&trim=true&dedupe=true&drop_empty_rows=true&empty_cells=keep&fill_value=N%2FA&line_ending=lfMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.