CSV to Excel

CSV to Excel reads a comma-separated file, uses the first row as headers, and downloads one Sheet1 workbook. Semicolon and tab files are not given a delimiter menu.

Comma file, first row as headers

Upload one CSV. The parser reads the text with the first row as column names and skips empty lines. Those names become the header row of a worksheet called Sheet1. Each later row becomes cells under those headers. The download is an xlsx workbook with that single sheet. A file that uses semicolons, tabs, or another delimiter is not detected and is not given a delimiter menu. A quoted comma stays inside one field, because the parser understands quotes. The upload cap is 25 MB. The file is uploaded, the workbook is built, and the temporary file is removed after the job.

One sheet, no formulas

There is no second sheet, no chart, and no formula. Excel to CSV goes the other way and only reads the first worksheet of a workbook. JSON to Excel builds Sheet1 from a JSON array or one object. This page wants a comma-separated text file, not a workbook and not JSON. A header that repeats can collapse columns, because rows are read as objects keyed by the header name. Rename duplicate headers in the CSV before you upload if every column must survive. A row with fewer fields than the header leaves those cells empty.

Where cell values go wrong

The parser keeps fields as text. A long account number or a code with a leading zero can still be changed when a spreadsheet opens the workbook, depending on how that app imports the cell. Do not assume a phone number or a ZIP code will keep its leading zero after you open the file. Dates are not given a date format. Encoding follows the text decode of the upload. A file saved in a legacy encoding can show the wrong characters. Save the CSV as UTF-8 if the letters look wrong. This page does not repair encoding and does not guess a separator.

What to check in the download

Open Sheet1 and compare the header row with the first line of the CSV. Compare the row count with the data lines you uploaded, not counting that header and not counting blank lines. If everything landed in column A, the file was probably not comma-separated. Fix the separator in the source and upload again. Excel to CSV can turn the first sheet back into a CSV later. It will not restore sheets this job never created. Count the data rows in the CSV, skip the header and the blank lines, and expect that count on Sheet1. A mismatch often means a comma inside an unquoted field split one column into two. The sample name,qty then Ada,2 is one header row and one data row.