Spreadsheet tools
Convert between Excel and CSV without losing your data.
On-device spreadsheet tools that preserve cell types, encodings, and the numbers you actually meant. Convert CSV ↔ XLSX in your browser, with nothing uploaded anywhere.
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CSV to XLSX Converter
Convert CSV to a real .xlsx Excel spreadsheet in your browser. Numbers stay numbers, text stays text, leading zeros don't get stripped. Works in Excel, Google Sheets, Numbers, LibreOffice.
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XLSX to CSV Converter
Convert XLSX (Excel) to CSV in your browser. Pick delimiter (comma, semicolon, tab) and encoding (UTF-8 BOM or plain). Clean output ready for databases, pandas, R, SQL imports.