CSV Cleaner
Paste in messy CSV, repair delimiters and stray whitespace, remove duplicate rows, and export clean JSON or a Markdown table.
What this does
This tool tidies up comma-separated data that has drifted out of shape: stray spaces around values, duplicate rows, blank lines, and inconsistent spacing after commas. Paste your data in, choose how you want it back, and it is cleaned in the browser – nothing is uploaded to a server.
You can export the result as clean CSV, as a JSON array of objects keyed on the header row, or as a Markdown table ready to drop into notes or a README.
What it cleans up
Real-world CSV data exported from a spreadsheet, copied from a web page, or stitched together by hand is rarely tidy. This tool fixes the common problems in one pass, and each fix is a checkbox you can turn off if you’d rather keep that quirk:
- Stray whitespace. Spaces that creep in around values or after commas (
Ada , London) are trimmed, so every field is clean at both ends. - Duplicate rows. Rows that are identical in every column – after trimming – are collapsed down to a single copy, keeping the first.
- Blank rows. Empty lines and rows containing nothing but separators are dropped, so the output has no gaps.
Throughout, values that are properly quoted are respected: a field wrapped in double quotes can contain commas, line breaks, and quote characters without being split apart or mangled.
Convert CSV as you clean
The output menu doubles as a quick converter. As well as clean CSV, you can turn your rows into:
- JSON – an array of objects, one per row, with keys taken from the header line. Handy for feeding data into code or an API.
- A Markdown table – ready to paste straight into a README, a wiki, or notes, with the header and separator rows built for you.
Everything runs locally in your browser, so even large pastes stay on your machine and the conversion is instant.
Common questions
How do I clean up a messy CSV?
Paste the data into the box above, leave the tidy-up options ticked, and press Clean. The result appears below, ready to copy. You can toggle any of the fixes off first if you only want some of them.
Does my data get uploaded anywhere?
No. All parsing happens in your browser. Closing the tab discards it.
What counts as a duplicate row?
After trimming, two rows with identical values in every column are treated as duplicates, and only the first is kept. Rows that differ in even one field are left alone.
Can it handle values that contain commas?
Yes. A value wrapped in double quotes can contain commas, line breaks, and escaped quotes (written as two double quotes), and it is treated as a single field. Clean CSV output re-quotes any value that needs it.
Can I convert CSV to JSON or Markdown?
Yes. Choose JSON or Markdown table from the Output menu before you press Clean. JSON gives you one object per row keyed on the header; Markdown gives you a table you can paste into documents.
Will it change my data?
Only in the ways you ask it to. It trims spaces, removes exact duplicate rows, and drops blank lines – it never alters the actual values inside your fields or reorders your columns.