What Excel is
An Excel workbook is a zip archive of XML parts describing sheets, cells, formulas, styles and charts. The .xlsx extension is that format; .xls is the older binary one from before 2007.
Finance, operations and anyone who received a file from finance or operations.
What ASCII Table is
An ASCII table is a grid drawn with plus signs, dashes and pipes. It renders identically in every terminal and every font.
Command line output, code comments, plain text email and commit messages.
What changes when you convert Excel to ASCII Table
Only the first sheet is read, and cells are read as the text Excel displays rather than the number underneath. That matters for dates: a cell showing 15/03/2026 arrives as that string, not as a serial number you would then have to decode.
Column widths are measured in display columns rather than characters, so a table with CJK or emoji content still lines up.
What carries over from Excel to ASCII Table
Excel records 4 things about a table that ASCII table has no way to hold.
Excel distinguishes a number from the text of a number; ASCII table does not, so every value arrives as text and has to be re-parsed by whatever reads it next.
An empty cell and a missing one are the same thing in ASCII table, so a null and an empty string in the Excel both come out blank and can no longer be told apart.
A line break inside a cell ends the row in ASCII table, so line breaks are replaced rather than carried through.
ASCII table marks its header cells differently from its data cells, so the first row is written with that marker.
Anything visual in the Excel - weight, alignment, colour, column widths - has no counterpart in ASCII table and is dropped. The values are what survives.