How to Open a CSV File in Excel Without Losing Data

Import the CSV through Excel

1. Open a blank workbook in Excel. On the Data tab, choose From Text/CSV and select your CSV file.
2. In the preview, check that the columns line up. Choose the actual delimiter used by the file, such as a comma, semicolon, or tab. If names or non-English characters look garbled, select the correct file origin or encoding.
3. For ZIP codes, product IDs, account numbers, or very long numbers, use the import transformation options to keep those columns as text. Also review dates that Excel might interpret using a different regional format.
4. Load the data into the workbook, inspect a few representative rows, and save the workbook as .xlsx if you need an Excel file.

Microsoft documents the From Text/CSV import process and its options for preserving data types. Menu names can vary by Excel version.

Why a CSV may look wrong when opened directly

A CSV is plain text with separators. It does not specify which fields are text, which are dates, or how many leading zeros a value needs. Excel therefore has to interpret the contents. A row such as 00123,東京,2026-09-25 might have its first field treated as a number, while the Japanese text may depend on the file encoding. If every value lands in one column, the chosen separator is likely wrong. Importing with an explicit delimiter and encoding lets you correct these issues before the data reaches the sheet.

Long identifiers also deserve attention: Excel can display long numbers in scientific notation or truncate numeric precision. Microsoft recommends importing identifier columns as text when their exact characters matter. If the CSV was already opened and saved after values changed, return to the original CSV and import it again; changing the display format later cannot always recover lost characters.

Reference: Microsoft Support: keeping leading zeros and large numbers.

Convert CSV to XLSX in your browser

If you want an Excel workbook without configuring Excel's import dialog, use our CSV to Excel converter. Upload the original CSV, check the parsed table, adjust the encoding or delimiter if needed, and download an actual .xlsx file. The converter writes CSV fields as text, so IDs and leading zeros remain text in the workbook. It processes the file in your browser and does not upload it to a server.

The tool starts with a ten-row preview and can show up to 100 rows on request. The downloaded workbook contains all parsed rows, not just the preview. For a CSV larger than the site's 20 MB upload limit, use Excel's import workflow or another desktop data tool instead.

Which method should you use?

Use Excel's From Text/CSV import when you need to set different data types for different columns, load the data into an existing workbook, or inspect the query before loading. Use the browser converter when you need a new .xlsx file quickly and want every CSV field preserved as text. In both cases, check a few rows with leading zeros, dates, separators inside quoted fields, and non-English characters before using the result.

Need the opposite direction? The Excel to CSV converter exports one CSV per worksheet by default, with multiple files bundled in a ZIP. CSV cannot carry workbook formatting, so keep the original Excel file as your editable copy.

Check the result before sharing it

Check more than the first row. Look at an identifier that begins with zero, a long reference number, a date, a cell containing a comma inside quotation marks, and a row with accented or non-Latin characters. Compare each value with the original CSV. A correct column count alone does not prove that every field was interpreted correctly. If a value differs, change the import settings or the converter's encoding and delimiter options, then try again from the original file.

Renaming report.csv to report.xlsx will not perform a conversion. The file contents would still be CSV text. Save the imported data from Excel as an .xlsx workbook, or use a converter that creates a real workbook. Keep a copy of the original CSV until you have verified the new file, especially when those values are used as IDs or keys in another system.