CSV doesn't have formulas, full stop. Every cell is just a string. The conversion process evaluates each formula in the source Excel file and writes the calculated value into the CSV, so a =SUM(A1:A10) becomes whatever number it currently produces. If you need formulas to survive the trip, you need to stay in Excel format or move to something like Google Sheets that has its own format.

How are dates handled?

Excel stores dates as serial numbers (the number of days since 1900) and displays them based on your locale settings. CSV stores them as text, which means the format you export with becomes the format the importer sees. Most tools default to ISO format (YYYY-MM-DD) because it's unambiguous; some use locale-specific formats which can cause '01/02/2024' to be interpreted as January 2nd in one place and February 1st in another. Pin down the format explicitly when you can.

What about multi-sheet workbooks?

CSV is single-sheet by definition, so multi-sheet workbooks need to be handled somehow. The three common approaches are exporting each sheet to its own CSV file (cleanest, most portable), letting you pick a single sheet and ignoring the rest (simplest), or concatenating sheets with a separator row (occasionally useful, often confusing). Pick whichever matches what your downstream system expects.

Will it preserve formatting?

No — fonts, colors, cell borders, merged cells, conditional formatting, comments, and all the other visual aspects of an Excel file are lost in conversion. CSV is plain text, so the tool preserves cell values, the basic distinction between numbers and text, and the row-and-column structure. If formatting matters, you need to either stay in Excel or use a richer format like HTML or PDF.

What encoding does it use?

Modern tools default to UTF-8, sometimes with a byte-order mark (BOM) for compatibility with Excel reopening the file. A few tools offer UTF-16 or Windows-1252 for legacy systems. Whatever you pick, verify that any Unicode characters in your data — emoji, accented Latin characters, Asian scripts — survive the conversion. Most modern systems expect UTF-8 by default; older or specialized systems may want something else.

How large can the Excel file be?

Browser-based tools comfortably handle files up to about 50MB. Past that, JavaScript memory limits start to bite and the conversion either gets very slow or fails outright. For larger files, drop down to pandas in Python (which can handle gigabytes if you have the RAM), use Excel's own Save As CSV, or look at dedicated command-line tools. Browser convenience and scale are a real trade-off.

Is the data sent to a server?

No, the conversion runs entirely in your browser. The file is read via the FileReader API, parsed by a JavaScript library like SheetJS, the CSV is generated locally, and you download it directly. Open the network tab during the conversion if you want to verify there's no upload happening. This matters when you're converting financial data, customer lists, or anything else you wouldn't want to send to a third party.

Excel to CSV

Convert Excel spreadsheets to CSV format online with multi-sheet support. Free XLSX to CSV converter with custom delimiter options.

Document Tools Data / JSON

Instant results

Upload Excel File

Supports .xlsx, .xls, .xlsm, .xlsb

About Excel to CSV Converter

The Excel to CSV converter reads Microsoft Excel files (.xlsx, .xls, .xlsm, .xlsb) directly in your browser and exports them as comma-separated value (CSV) files. It supports multi-sheet workbooks, letting you select which sheet to export and preview the data before downloading.

Built on the SheetJS library, this tool parses Excel binary formats entirely client-side. No file is uploaded to any server, so your spreadsheet data remains private and secure on your device.

Key Features

Multi-Sheet Support

Workbooks with multiple sheets display all sheet names with row and column counts. Click any sheet to preview its data and export it individually.

Data Table Preview

Preview the first 20 rows of any sheet in a formatted table. Verify your data looks correct before exporting to avoid unnecessary re-conversions.

Custom Delimiter

Choose your output delimiter: comma, semicolon, tab, or pipe. Semicolons are common in European locales where commas serve as decimal separators.

Wide Format Support

Reads .xlsx (Office Open XML), .xls (legacy BIFF), .xlsm (macro-enabled), and .xlsb (binary) formats. Covers virtually all Excel versions from 97 to 365.

UTF-8 with BOM

Output CSV includes a UTF-8 byte order mark (BOM) for correct display of international characters when opened in Excel or other spreadsheet applications.

100% Client-Side

No data is uploaded to any server. The entire conversion runs in your browser using JavaScript, keeping your spreadsheet content private and secure.

When to Convert Excel to CSV

Database Imports

Most databases and data pipeline tools accept CSV as a primary import format. Convert Excel spreadsheets to CSV before loading data into PostgreSQL, MySQL, MongoDB, or data warehouses.

Cross-Platform Compatibility

CSV is a universal plain-text format that works on any operating system and with virtually any programming language. Use CSV when you need maximum compatibility across tools and platforms.

Version Control and Diffs

CSV files are plain text, making them ideal for version control with Git. Changes between versions are easy to diff, unlike binary Excel formats that produce opaque changesets.

How to Use Excel to CSV

Upload Excel file

Drag the .xlsx or .xls file into the drop zone, or click to pick it from a file dialog. The tool parses the workbook in your browser and shows you which sheets it found along with a preview of the contents, which is useful for confirming you uploaded the right file before committing to the conversion.

Choose sheet(s) to convert

If the workbook has multiple sheets, pick which ones you want. Most tools let you export each sheet to its own CSV (the cleanest option for downstream processing), select just one sheet for a single-file output, or combine multiple sheets in some way. The choice depends on what your importer expects.

Configure options

Set the output encoding (UTF-8 is the right default unless you have a specific legacy system), the delimiter (commas are standard, but tabs or semicolons work too), whether to include the header row, and the date format. The defaults work for most use cases — only change them if your downstream system has specific requirements.

Download CSV

Click the download button and the tool produces the CSV file directly in your browser. Nothing is uploaded to a server. From there you can open it in a text editor to verify the output, drop it into a database tool for import, or feed it to your analytics or scripting workflow.

When to Use Excel to CSV

Database imports

Business teams live in Excel, but most databases want CSV when you bulk-import data. Converting an XLSX to CSV gives you something that drops cleanly into a Postgres COPY command, a MySQL LOAD DATA INFILE, or pretty much any ETL tool. The conversion happens in your browser, which matters when the spreadsheet contains data you'd rather not upload to a third party.

Data analysis tools

Pandas, R, and most command-line data tools speak CSV natively and treat XLSX as a second-class citizen. Converting your Excel exports to CSV up front saves you from fighting with version-specific xlsx readers, simplifies scripting, and tends to produce more predictable results when you're chaining processing steps in an automated pipeline.

Cross-platform sharing

CSV opens in any text editor on any operating system, while Excel files need either Microsoft Office, LibreOffice, or one of a handful of compatible tools. When you're sharing data with Linux users, mobile users, or automation systems that don't have Excel parsers, converting to CSV first eliminates a whole class of compatibility headaches.

Multi-sheet decomposition

A workbook with five tabs becomes five CSVs, one per sheet. That's helpful when you have scripts that process one CSV at a time, when you want to share just one sheet without exposing the rest, or when you're trying to simplify a sprawling workbook into separately tracked files. The tool typically lets you pick whether to export one sheet or all of them.

Excel to CSV Examples

Single sheet conversion

Input

Excel file: report.xlsx with 1 sheet, 100 rows

Output

CSV file: report.csv — comma-separated, header row preserved as the first line, UTF-8 encoded.

This is the bread-and-butter conversion. The tool reads the XLSX, writes a CSV with proper escaping per RFC 4180 (fields containing commas or quotes get wrapped in double quotes), and preserves the header row. Type information disappears since CSV is plain text, but the values are intact.

Multi-sheet workbook

Input

Q1.xlsx with sheets: Sales, Inventory, Returns

Output

Three CSVs: Q1_Sales.csv, Q1_Inventory.csv, Q1_Returns.csv. Each sheet becomes its own file, named after the source sheet.

When CSV's one-sheet-per-file constraint runs into a multi-sheet workbook, decomposition is the cleanest answer. The naming pattern (workbook prefix plus sheet name) makes it easy to identify which file came from where, which matters when you've got several workbooks with overlapping sheet names.

Formula handling

Input

Excel with =SUM(A1:A10), =VLOOKUP(...)

Output

CSV contains the calculated values, not the formulas themselves. Formulas evaluated at export time, results stored as plain text.

CSV doesn't have a concept of formulas — every cell is just a string. The conversion evaluates each formula in Excel and writes the resulting value, so a SUM that produces 1234.56 ends up as '1234.56' in the CSV. Fine for snapshots and data exchange; not what you want if you need formulas to survive the trip.

Tips & Best Practices for Excel to CSV

1.Verify the encoding. Excel saves in different encodings depending on the version and locale, while CSV is usually expected to be UTF-8. After conversion, do a quick eyeball test on any cells with emoji, accented characters, or non-Latin scripts to confirm they survived.
2.Watch out for date format ambiguity. Excel stores dates as serial numbers internally and displays them per locale; CSV stores them as plain text. The string '01/02/2024' means January 2nd in the US and February 1st in most of Europe, and that ambiguity has caused real production bugs. ISO format (YYYY-MM-DD) eliminates the problem.
3.Numbers with leading zeros lose their padding. '00123' becomes '123' once it's interpreted as a number, which breaks zip codes, product codes, and anything where the format itself is meaningful. Pre-format those columns as text in Excel (with a leading apostrophe) before exporting.
4.Browser-based conversion has practical limits around 50MB of Excel input. For larger workbooks, drop down to pandas (Python's read_excel + to_csv), use Excel itself with Save As CSV, or use a dedicated server-side tool. The browser limit is JavaScript memory rather than algorithmic, so it varies a bit by machine.
5.CSV genuinely doesn't support multiple sheets. If you need to preserve the multi-sheet structure, your options are exporting each sheet separately, bundling them into a ZIP, or stepping up to a format like XLSX or Parquet that does support multiple tables.
6.Always sanity-check the result. Open the CSV in a text editor (not Excel — Excel will reinterpret things) and look for proper escaping of commas and quotes, the right encoding, and no obvious corruption. A 30-second eyeball check catches most of the issues that would otherwise blow up your import.

Frequently Asked Questions

The modern formats are fully supported — .xlsx for Excel 2007 and newer, and .xlsm for files with macros (though the macros themselves don't survive the conversion since CSV doesn't have a concept of them). Legacy .xls files from Excel 97 through 2003 are supported by most tools. OpenDocument .ods files are hit or miss depending on the implementation. In all cases the tool converts cell values, with formulas evaluated to their results.

Excel to CSV

About Excel to CSV Converter

Key Features

Multi-Sheet Support

Data Table Preview

Custom Delimiter

Wide Format Support

UTF-8 with BOM

100% Client-Side

When to Convert Excel to CSV

Database Imports

Cross-Platform Compatibility

Version Control and Diffs

How to Use Excel to CSV

Upload Excel file

Choose sheet(s) to convert

Configure options

Download CSV

When to Use Excel to CSV

Database imports

Data analysis tools

Cross-platform sharing

Multi-sheet decomposition

Excel to CSV Examples

Single sheet conversion

Multi-sheet workbook

Formula handling

Tips & Best Practices for Excel to CSV

Frequently Asked Questions

Related Tools

CSV to Excel

PDF Merge

PDF Split

PDF Rotate

PDF to Text

HTML to PDF