CSV Whitespace Normalizer

About this tool

Stray whitespace is the quietest way for a CSV to be wrong. Berlin and Berlin are different keys, so a join drops rows, a VLOOKUP returns #N/A, a GROUP BY splits one city into two, and a duplicate check finds nothing to merge — all while the spreadsheet on screen looks perfectly fine, because a space renders as nothing.

A plain trim only fixes half of it. Trimming turns " Ada Lovelace " into "Ada Lovelace" and leaves the three spaces in the middle, so the value still does not match Ada Lovelace. This tool handles both ends and the interior: it collapses runs of whitespace inside a value down to a single space, or removes them outright when the value is a SKU, an IBAN or a part number that should have no spaces at all.

It works on the parsed table, not on the raw text. Fields are read with a real RFC 4180 parse, so quoted values keep their quoting, an embedded comma or newline never breaks a record, the field separator round-trips unchanged, and a ragged row keeps its length. Only whitespace changes — nothing is retyped, reordered, dropped, or invented.

Worked example

Input (defaults everywhere — the dots below mark the spaces you cannot see):

name,city,sku
··Ada···Lovelace·,·New···York·,··AB·12··CD·
Grace Hopper,Berlin·,XY34

Output:

name,city,sku
Ada Lovelace,New York,AB 12 CD
Grace Hopper,Berlin,XY34

Row 3 shows what "already clean" looks like: Grace Hopper keeps its single space, and only the stray one after Berlin goes. If you also wanted AB 12 CD to become AB12CD — but only in that column — set Whitespace inside the value to Remove and Only these columns to sku.

The invisible ones

By default whitespace means the whole Unicode White_Space set, not just space and tab. That matters because the characters a spreadsheet, a PDF, or a web page leaves behind on copy-paste are usually not plain spaces:

All of them are trimmed and collapsed like an ordinary space. Switch What counts as whitespace to ASCII only when a non-breaking space is load-bearing in your data and must survive.

Zero-width characters are deliberately not included: U+200B (zero-width space) and U+FEFF (BOM / zero-width no-break space) have White_Space=No, they are not padding, and stripping them is a different job with different consequences.

Controls

• Delimiter — comma (default), tab, semicolon, pipe, any single character, or auto to sniff the separator from the first line. Whatever comes in goes back out.
• Trim the cell edges — both ends (default), leading only, trailing only, or none to leave the edges alone and rewrite just the interior. An edge run that survives is copied verbatim, so one-sided trimming really is one-sided.
• Whitespace inside the value — collapse every run to one plain space (default), remove it entirely, or keep it, which makes this a pure trim.
• What counts as whitespace — unicode (default) or ascii (space, tab, newline, carriage return, form feed).
• Only these columns — comma-separated column names (needs a header), 1-based positions, and inclusive ranges, e.g. name,city or 1,3-5. Blank means every column.
• First row is a header — on by default. The header supplies the names used by the column filter.
• Normalize the header cells too — on by default, because first name is exactly the kind of header that loads as a column nobody can reference. Turn it off to copy the header row through byte-for-byte.

Limits and edge cases

The table is capped at 5,000,000 bytes. A cell that is only whitespace becomes empty under every trim setting except none. Under collapse, a newline embedded inside a quoted cell counts as a whitespace run and becomes one space, which is usually what you want but does flatten a deliberately multi-line cell — choose keep to preserve it. A column selector token that parses as a number or a range is read as a position, so a header literally named 3 or 2-4 has to be selected by its position instead of its name. Output rows are terminated with a single newline (\n) and the result always ends with one. Everything runs locally in your browser — the table is never uploaded.

FAQ