Convert CSV to Excel — Free Online Converter

CSV (Comma-Separated Values) is the simplest tabular data format — a plain text file where each line represents a row and commas delimit columns. Despite its simplicity, CSV is the lingua franca of data exchange: databases export it, spreadsheets import it, programming languages parse it natively, and virtually every data tool on earth supports it. However, CSV has no concept of data types, formatting, formulas, charts, or multiple sheets.

Microsoft Excel is the dominant spreadsheet application for business, finance, and data analysis. Excel files (XLSX) store rich data with formatting, formulas, conditional formatting, charts, pivot tables, data validation, and multiple worksheets in a single file. Converting CSV to Excel transforms raw data into a structured workbook ready for analysis, visualization, and professional presentation.

Raw CSV data is unformatted plain text — every value is a string, there are no column widths, no header highlighting, no number formatting, and no formulas. Converting to Excel immediately makes the data usable in a business context: columns auto-size, numbers are recognized and right-aligned, dates parse into native date types, and you can immediately create charts, pivot tables, and formatted reports.

Excel files are also the standard format for sharing data with business stakeholders, clients, and management teams. A CSV might be technically correct but looks unprofessional when opened in a spreadsheet. Converting to Excel and applying even basic formatting — bold headers, column filters, number formatting — transforms raw data into a polished deliverable that commands confidence.

LibreOffice processes the CSV file by parsing delimiters (comma, semicolon, or tab), detecting text encoding (UTF-8, Latin-1, Windows-1252), and applying type inference to classify each column as text, number, date, or boolean. The parsed data is written into an XLSX workbook using Open XML format. Column widths are calculated based on content length. Number values are stored as native Excel numeric types with appropriate formatting. Dates detected from common patterns (YYYY-MM-DD, MM/DD/YYYY, DD.MM.YYYY) are converted to Excel serial date numbers. The output XLSX file is a ZIP-compressed package of XML files conforming to the Office Open XML standard.