Convert CSV to Excel

What happens when you double-click a CSV

A CSV is plain text: it does not say which separator it uses or which encoding it was saved in. Excel guesses using your regional settings and fails in the two classic ways — every column crammed into the first one, or every accented character turned into gibberish.

Here the file is analysed before anything is written, and what you download is a real .xlsx with proper columns and proper types.

The separator is detected for you

The four usual candidates — comma, semicolon, tab and pipe — are counted outside quotes across the first lines. The winner is the one that repeats consistently, because a real separator appears the same number of times on every row, whereas a comma inside a sentence does not.

If your file is an odd case, you can force the separator instead of leaving it on "Auto".

The encoding is detected too: a BOM is honoured when present, otherwise UTF-8 is tried and Latin-1 is used as the fallback when the bytes are not valid UTF-8 — which is what Excel on Windows usually produces.

Types: the actual reason to convert

Wrapping text in an .xlsx achieves little if every column is still text. With "Detect types" enabled, each cell is interpreted:

• Numbers become numbers, so you can sum them and sort largest-first instead of alphabetically.
• Dates in YYYY-MM-DD form (with or without a time) become dates.
• true and false become booleans.

Decimals hide a known trap: 1.234,56 and 1,234.56 are the same amount written by two different people. The rule applied is that when both symbols appear, the last one is the decimal separator; when only one appears and it repeats, it is the thousands separator. In the one genuinely ambiguous case — 1,234 — the page language decides.

Codes with leading zeros

A 007, a postcode or a product reference starting with zero is not a number: it is an identifier. Converting it would drop the zero for good. That is why anything starting with 0 followed by a digit is kept as text.

To pin a specific value down, prefix it with a single quote ('0034): it is the Excel convention and here it also means "this is text, do not interpret it".