CSV to Excel Converter

CSV to Excel with the values you expect

Double-clicking a CSV file hands it to your spreadsheet program, which then decides on its own how to read every cell. Depending on the app and your regional settings, an employee number such as 00417 may lose its zeros, a 16-digit reference may be shown in scientific notation, and a semicolon file may land in a single column. This CSV to Excel converter makes those decisions explicitly and saves the result as an .xlsx workbook, so the file opens the same way everywhere.

Example

employee_id,name,phone,start_date,salary
00417,Grace Hopper,+1 555 0100,2021-03-01,98000
00982,Alan Turing,+44 20 7946 0000,2019-11-15,105000.50

After Convert to Excel, the output panel previews the sheet as CSV:

employee_id,name,phone,start_date,salary
00417,Grace Hopper,+1 555 0100,2021-03-01,98000
00982,Alan Turing,+44 20 7946 0000,2019-11-15,105000.5

and the status bar reports Excel workbook ready (1 sheet, 8.7 KB) — click Download. In the downloaded workbook the IDs, names, phone numbers and dates are text cells, while the salaries are real numbers you can sum. The preview shows 105000.5 because the value is stored as a number; apply a number format in Excel to display two decimals.

How cells are typed in the workbook

The 15-digit limit matches Excel's own precision: Excel stores numbers with 15 significant digits, so a longer card, order or tracking number typed as a number would have its last digits replaced by zeros. Keeping such values as text protects them.

Dates are deliberately left as text so that no day and month get swapped. If you need real date cells for calculations, select the column in Excel and use Data › Text to Columns, or a formula such as DATEVALUE.

Options explained

• Sheet name – the name of the worksheet tab, Sheet1 by default. Excel does not allow \ / ? * [ ] : or names longer than 31 characters, so those characters are removed: Staff/2024 becomes Staff2024.
• Detect numbers & booleans – on by default and usually what you want. Untick it to store every cell as text, for example when the sheet is only a container for codes; formulas like SUM will then ignore those cells.
• First row is header – writes the header as the first row of the sheet and uses it to size columns.
• Delimiter – Auto-detect, or force comma, semicolon, pipe or tab for files that confuse detection.
• Nest dotted headers and Flatten nested objects – only relevant when headers contain dots; with the defaults, columns are kept as they are.

Column widths are calculated from the header and the first 200 rows of data, between about 10 and 60 characters, so long text does not produce a giant column and short codes are not cut off.

Formatted numbers and formulas

Only plain numbers become numeric cells. Values that already carry formatting, such as 1,250, $12 or 6%, are stored as text, so remove the symbols and separators in the CSV if you need to calculate with them. A cell starting with = is also stored as text rather than as a live formula, which means a CSV from an untrusted source cannot slip a formula into the workbook.

When this conversion is worth it

• Sending data to colleagues or clients who will open it in Excel and should not have to use an import wizard.
• Uploading to a system whose import form accepts only .xlsx.
• Archiving an export with product codes, ZIP codes or account numbers that must keep their exact form.
• Delivering a semicolon or tab separated file to someone whose spreadsheet expects commas, or the other way round.

The downloaded file is named after the tool, csv-to-excel.xlsx; rename it as needed. To check the workbook without opening a desktop app, drop it into the Excel viewer. For the reverse direction, Excel to CSV exports a sheet as text, and JSON to Excel builds the same kind of workbook from JSON.

Privacy

The workbook is assembled in your browser by a JavaScript spreadsheet library; the CSV is not uploaded to create it. Only Load URL and Save & Share pass data through our server.