Convert CSV to Excel

Convert CSV data into a structured Excel workbook without uploading the source file. FileGizmo reads the header row, preserves every field as text, freezes the headings, and adds a filter so the result is immediately useful in Excel, LibreOffice, Numbers, or another spreadsheet application.

The conversion runs in a dedicated browser worker. Your page remains responsive while the CSV is parsed and the XLSX package is assembled locally. No account, server transfer, or waiting queue is involved. Keeping values as text also avoids unwanted spreadsheet formula execution and prevents identifiers such as postal codes or product numbers from losing leading zeroes.

Automatic delimiter detection works for common comma, semicolon, tab, and pipe-delimited files, or you can choose the delimiter yourself. You can also provide a worksheet name before converting. Excel imposes a maximum of 1,048,576 rows and 16,384 columns per worksheet; FileGizmo detects those limits and explains when a large source should be split first.

An XLSX workbook adds useful structure around plain delimited text. The first source row becomes the header row, remains visible while scrolling, and receives an autofilter so users can sort or narrow records immediately. The converter creates one worksheet and names it from your input or chosen label after removing characters Excel does not allow. It does not invent charts, formulas, styling rules, or data relationships that are absent from the CSV.

FileGizmo intentionally writes imported fields as text. Automatic spreadsheet typing can damage real data: 00123 may become 123, a long account number may display in scientific notation, and a value beginning with = can be treated as a formula. Text preservation keeps the source characters visible and reduces formula-injection risk. Users can convert selected columns to dates or numbers later when they understand the intended meaning.

Correct delimiter detection is essential. A semicolon-separated export parsed as commas may appear to have one giant column; quoted commas inside addresses must not create extra cells. Check the preview summary and override the separator if the reported columns do not match the source. UTF-8 text supports names and scripts beyond ASCII, but a damaged or differently encoded source may need to be re-exported correctly before conversion.

Excel’s worksheet limits are fixed. A source beyond 1,048,576 rows or 16,384 columns cannot fit in one sheet, and browser memory becomes a practical concern much earlier on smaller devices. Split huge exports into meaningful files or process them with a database tool. For ordinary operational exports, a desktop browser offers more memory and a smoother download experience.

Open the workbook after conversion and confirm headings, leading-zero identifiers, Unicode values, row count, and several fields containing quotation marks or line breaks. The XLSX package is generated locally and named from the CSV. No server receives the dataset, but the downloaded workbook contains the same sensitive information in a more convenient format, so access controls still matter.