CSV to Excel Table Preview Online — Free Viewer

No, and it is worth knowing up front. The page only draws your data as a table in the browser; there is no save-as-XLSX button. For a real Excel file, import the original CSV in the spreadsheet application itself, or use a converter that returns a file. The preview is for checking the shape of an export quickly, not for producing a document.

Nothing: a semicolon is detected on its own, and if the guess misses you can choose it in «Delimiter:» alongside the comma and the tab. European Excel locales and many bank portals export exactly that, and the file no longer has to be rewritten in a text editor first. The delimiter the file was parsed with is shown in the status line under the table.

Almost always a comma inside a value: an address like New York, NY or a thousands separator splits the row into an extra field. The standard fix is wrapping such values in double quotes. Find the row whose field count differs from the header and repair it before previewing again.

A few thousand rows is the sensible limit. The grid is rendered straight into the browser DOM, so an export with tens of thousands of rows will slow the tab down noticeably or hang it on a weak device. For a structure check, the first two hundred rows are usually enough to expose formatting errors.

Yes, provided you copy from a UTF-8 file. Trouble starts with Windows-1251 exports: opened without declaring the encoding, the labels are already mangled before you paste them. Re-save the source as UTF-8 and copy the data again.

No. A script on the page parses the string and builds the table, and none of your data is sent over the network. What you pasted does stay in the field until you reload, though, so on a shared computer it is worth clearing the box after previewing a statement or a customer list.