What is a Transpose CSV?

Transposing a CSV means swapping rows and columns: what was a row of values becomes a column, and every header lands in the first column of the output. Spreadsheets can do this with a paste-special trick, but when the data lives as a text file — a database export, a test fixture, an API dump — this tool does it in one paste.

The classic use case is data that was recorded the wrong way around: measurements per day arranged as columns when you wanted days as rows, or a lookup table where the keys ran along the top. Transposing once is faster than restructuring the source.

Two groups of options matter for untidy input. The separator and quote-character settings tell the parser how fields are delimited, and the comment character lets you ignore annotation lines that are not part of the table. For ragged rows where columns do not line up, you can fill missing cells with empty values — keeping the grid rectangular — or with a custom placeholder such as N/A, so downstream tools can tell missing data apart from genuinely empty fields.

Like every tool on this site, transposition happens locally in your browser and the data never leaves your machine, so exports with personal or confidential columns are safe to paste. The output is plain CSV text you can copy or save directly, with no file round trip.