Excel to CSV converter

How to convert Excel to CSV

1. Choose or drop one XLSX or Excel 97–2003 XLS file.
2. Select the worksheet. Each download contains one sheet.
3. Choose formatted text or underlying values and a delimiter. Spreadsheet-safe export is optional and clearly marks intentional changes.
4. Select Prepare CSV preview, review the notes, then Download CSV. Repeat for other worksheets if needed.

Choose how cell values are exported

Formatted text is the default. The reader applies stored number formats, helping retain displayed leading zeros, dates, percentages and currencies. This is not a pixel-exact reproduction of Excel: locale-dependent formats, conditional formatting and unusual custom formats can differ. Review identifiers and dates in the preview.

Underlying values keeps text strings and exports stored numbers without display formats. Dates stored numerically become Excel serial numbers; numeric 123 displayed as 00123 exports as 123. Neither option can recover identifier digits already lost to Excel’s numeric precision.

Formulas, hidden data and merged cells

Formulas are never evaluated. CSV uses saved formula results, which may be stale. If the chosen sheet contains a formula without a saved result, download is blocked: recalculate and save the file in Excel or LibreOffice first. Excel error cells remain error text and are counted.

Hidden sheets are labelled and selectable; hidden rows and columns are included. Merged cells are not filled across or down. Blank positions stay empty. Output begins at A1 and extends to the worksheet’s reported or actual used extent, retaining leading and interior blank rows and columns. Other sheets, styles, images, comments, hyperlinks and macros are not part of CSV. They are not executed or followed.

CSV text types and spreadsheet safety

CSV has no cell types. Even a correctly exported identifier can be reinterpreted when opened directly in Excel. Import sensitive columns as Text; see how to keep leading zeros in Excel and CSV. For the reverse direction, use CSV to Excel with text cells.

Data-preserving export is the default. For untrusted data, optionally enable spreadsheet-safe export. It prefixes formula-like text with an apostrophe and reports the number of changed values in the preview. This changes exported text, including formula-like negative text; ordinary negative numeric values remain unchanged. Do not remove protective prefixes or convert untrusted text to formulas when reopening a CSV.

Your workbook stays on your device

Parsing and CSV generation run in a local browser worker with no uploads, accounts, analytics or external processing. The spreadsheet reader loads only when you choose a workbook. You can cancel processing and download the original workbook unchanged.

Supported files and limits

XLSX and Excel 97–2003 compound-file XLS, up to 5 MB and 50 worksheets. Each exported sheet is limited to 100,000 rows, 256 columns and 200,000 rectangular output fields. XLSX expanded archive content is limited to 32 MB and 2,048 entries. CSV output is limited to 20 MB. Processing stops after 30 seconds. Oversized sheets are rejected without truncation.

Password-protected or encrypted workbooks, ZIP64 archives, older raw BIFF files, XLSB, XLSM, ODS and files renamed from HTML or CSV are not supported. Device memory varies; worker isolation, decompression checks and limits reduce risk but cannot guarantee a hard memory ceiling for hostile files. Use current browsers with Web Workers and XLSX decompression support.

Need to clean the exported CSV?

No cleaning, trimming, duplicate removal or inferred values are applied here. Use CSV Repair & Cleaner separately to inspect and review changes after conversion.