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 MATLAB is
MATLAB cell arrays combined into a table with the table() function.
Engineering and research code.
What changes when you convert Excel to MATLAB
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.
One cell array per column, then a single table() call. Column names are sanitised to valid variable names.
What carries over from Excel to MATLAB
Excel records 3 things about a table that MATLAB has no way to hold.
An empty cell and a missing one are the same thing in MATLAB, 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 MATLAB, so line breaks are replaced rather than carried through.
MATLAB 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 MATLAB and is dropped. The values are what survives.
Both formats record types, so numbers, booleans and nulls survive as themselves rather than as text.