Why does my CSV open in one Excel column?

Excel or the converter guessed the wrong delimiter. The file may use semicolons, tabs, or pipes instead of commas.

Will leading zeros be preserved?

Check columns such as ZIP codes, product IDs, invoice numbers, and phone numbers. Spreadsheet software often tries to treat them as numbers, which can remove leading zeros.

Why do accents or special characters look broken?

That is usually an encoding mismatch. UTF-8 is the safest modern default, but older exports may use a different encoding.

Will dates stay in the same format?

Not always. Dates can be interpreted differently depending on locale, such as month/day/year versus day/month/year. Review date columns after conversion.

Can I convert very large CSV files?

Large files depend on browser memory. If the file has hundreds of thousands of rows, split it into smaller CSVs before converting.

Is XLSX better than CSV?

XLSX is better for spreadsheets, formatting, and sharing with Excel users. CSV is better for simple data exchange between systems.

Why does my CSV open in one Excel column?

Excel or the converter guessed the wrong delimiter. The file may use semicolons, tabs, or pipes instead of commas.

Will leading zeros be preserved?

Check columns such as ZIP codes, product IDs, invoice numbers, and phone numbers. Spreadsheet software often tries to treat them as numbers, which can remove leading zeros.

Why do accents or special characters look broken?

That is usually an encoding mismatch. UTF-8 is the safest modern default, but older exports may use a different encoding.

Will dates stay in the same format?

Not always. Dates can be interpreted differently depending on locale, such as month/day/year versus day/month/year. Review date columns after conversion.

Can I convert very large CSV files?

Large files depend on browser memory. If the file has hundreds of thousands of rows, split it into smaller CSVs before converting.

Is XLSX better than CSV?

XLSX is better for spreadsheets, formatting, and sharing with Excel users. CSV is better for simple data exchange between systems.

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How it works

Upload the CSV

Add the CSV file from your database, CRM, form export, or analytics tool. If columns look wrong, the delimiter may not be a comma.

Convert to XLSX

The data is parsed into rows and columns and saved as an Excel workbook. Header rows and common data types are preserved where possible.

Check the spreadsheet

Open the XLSX and inspect columns with dates, ZIP codes, IDs, currency, and accented names before sending or importing it.

Frequently asked questions

About CSV to Excel

CSV is simple until Excel guesses wrong. A file exported from a CRM, database, email tool, analytics platform, or accounting system may use commas, semicolons, tabs, or another delimiter. It may use UTF-8 encoding, or it may come from an older system that turns accents into strange symbols. Excel may also treat ZIP codes, product codes, and long IDs as numbers, removing leading zeros or showing scientific notation. This converter turns CSV into an XLSX workbook so the data opens as a spreadsheet instead of raw text. It is useful when a client, coworker, or import tool expects Excel format, or when you want to inspect CSV data without manually splitting columns. After conversion, check the first rows, the last rows, and any column with codes, dates, phone numbers, prices, or accented names. CSV conversion is not just about opening the file; it is about making sure the values survived the trip.

Updated June 2026: Expanded troubleshooting for one-column imports, delimiters, UTF-8 accents, leading zeros, long IDs, and date-format surprises.

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Related guides

How to Convert CSV to Excel Without Breaking Columns

Fix common CSV to Excel problems: everything in one column, broken accents, lost leading zeros, and dates changing format.