CSV to Excel moves values, not the whole workbook
Open a CSV in a real workbook when you need filters, column widths, or a second sheet.
The CSV is read and saved as XLSX.
Dates and extra sheets after CSV to Excel
A CSV has no formatting to recover. If columns look merged, the file was probably not quoted correctly.
A related step, if you still need one, is Excel to CSV.
CSV to Excel without the extra promises
CSV to Excel sits on this site because CSV and XLSX are not interchangeable, even when they look similar in a file list. Open a CSV in a real workbook when you need filters, column widths, or a second sheet. Mail merges, databases, and Google Sheets imports are typical CSV jobs. Spreadsheets, charts, and CSV exports start here for most offices in 2026.
The CSV is read and saved as XLSX.
Read this about CSV before you upload
CSV is one table in text: a row per line, commas between cells. Databases and import forms accept it. A comma inside a name splits one column into two unless the field is quoted. Extra sheets disappear.
Keep the workbook. CSV is not a backup of formulas.
Read this about XLSX before you send the download
The download has to be XLSX, because that is the format the next step named. Spreadsheets, charts, and CSV exports start here for most offices in 2026. Values, dates, and several sheets can travel when the tool writes a real workbook.
Afterward, check dates, leading zeros, and whether a second sheet was left behind.
Keep, check, then delete
People lose time when they convert before they know which rule failed. Size, pixel dimensions, codec, font encoding, and layout are different rules. CSV to Excel only addresses the CSV to XLSX step. Open a CSV in a real workbook when you need filters, column widths, or a second sheet. The CSV is read and saved as XLSX. A CSV has no formatting to recover. If columns look merged, the file was probably not quoted correctly. The file stays in your browser and is not uploaded. The limit is 100 MB. Keep the original until the download has been opened in the program that will use it. Do the test with a short or simple file first when the real file is large. A one-page PDF, a single photo, or a one-minute clip will show you whether the output is the kind of file you needed. After that test looks right, run the real file once. Keep both the CSV original and the XLSX download until the receiving person or the upload form accepts it. Spreadsheets break at quiet places: a second sheet, a date that changed, a leading zero that vanished, a comma inside a name. After CSV to Excel, open the result in a text editor as well as Excel. Excel guesses types and hides the delimiter. The workbook you calculated in is still the master.
Here is the decision for CSV to Excel. You start with CSV and you stop when a real program accepts XLSX. Almost every data tool can read a simple CSV. A conversion aimed at CSV or JSON flattens that richness. Charts and macros are not the point. If those two sentences describe a tradeoff you do not want, do not convert. Renaming the extension by hand will not do this job. Running the tool twice on its own output will not do it either.
A CSV has no formatting to recover. If columns look merged, the file was probably not quoted correctly.
A related step, if you still need one, is Excel to CSV.
Other jobs start from the homepage, where each tool is named for the conversion it actually does.