Frequently asked questions
How are duplicate rows detected?
Two rows are duplicates when every cell matches exactly (after optional whitespace trimming). With "first row is a header" ticked, the header is always kept.
My file uses semicolons, not commas — will it work?
Yes. The delimiter is auto-detected (comma, semicolon, tab or pipe), and you can also set it manually — plus convert to a different delimiter on output.
Is my data private?
Completely. The file is parsed in your browser's memory — customer lists and financial exports never leave your machine.
What's the size limit?
Around 30 MB, which is roughly 200,000–500,000 rows depending on width. Beyond that, browsers get slow.
Why exported CSVs are always a mess
CSV is the universal export format, which is exactly why it's so often messy. Systems bolt duplicate rows together, leave blank lines where records were skipped, pad cells with stray spaces, and disagree about whether the separator should be a comma, a semicolon or a tab. Drop that file into Excel and you get misaligned columns and double-counted rows. This tool fixes the common problems in one pass so the file imports cleanly.
What each option does
- Remove duplicate rows — drops rows where every cell matches another row exactly (after optional trimming). With "first row is a header" ticked, the header is always protected.
- Remove empty rows — clears the blank lines that break Excel's "select all" and throw off row counts.
- Trim whitespace — strips leading and trailing spaces inside cells, the invisible culprit behind failed lookups and mismatched joins.
- Remove empty columns — deletes columns that are completely blank top to bottom, a common artefact of over-wide exports.
Getting the delimiter right
The most common reason a CSV "won't open properly" is a delimiter mismatch — European exports frequently use semicolons because the comma is a decimal separator there. The cleaner auto-detects comma, semicolon, tab and pipe, and you can override it manually if the guess is wrong. You can also convert the delimiter on the way out — for instance, turn a semicolon file into a standard comma file so it opens correctly in an English-language copy of Excel.
Handling large files, privately
The tool comfortably handles files up to around 30 MB — very roughly 200,000 to 500,000 rows depending on how wide they are — before the browser starts to slow down. Everything is parsed in your browser's memory, so customer lists, financial exports and other sensitive data never leave your machine. A common workflow is to extract a table with PDF to Excel and then clean the CSV here before importing it anywhere.