Convert CSV to XLS online

To convert CSV to XLS, upload the CSV file, start the conversion and download the result. LibreOffice opens the CSV and saves it as XLS; styles and tables carry over where XLS supports them.

◈ Encrypted transfer◷ Short retention⊘ No watermark◎ Works on every device

CSV to XLS at a glance

Converts: CSV spreadsheet format → XLS spreadsheet format
Engine: LibreOffice
Privacy: Private download link; files are deleted after 6 hours. No account needed.

How CSV turns into XLS: Workbook object-model rebuilding

Cells, sheets, formulas, types, and print settings are read from CSV and mapped into structures XLS can express. A displayed total is not enough evidence; formulas and leading zeros may have changed underneath it. CSV is parsed as encoded text with a chosen delimiter and quoting rules; it supplies neither workbook formulas nor an authoritative type for each field. XLS output targets the legacy binary Excel grid and its older row, column, formula, chart, macro, and date-system limitations.

Read as plain-text rows and fields separated by a delimiter rather than a workbook object model. Rebuilt as the legacy binary Excel workbook with cells, formulas, formats, and older size limits.

Need a different output? See all CSV conversion options.

Background reading: the field guide to file formats covers why a format is a set of tradeoffs rather than a label.

CSV

CSV spreadsheet format

Used for structured data meant to be sorted, filtered, and computed.

Family: Documents
MIME: text/csv

→

XLS

XLS spreadsheet format

Designed for structured rows and columns of calculated data.

Family: Documents
MIME: application/vnd.ms-excel

Acceptance evidence for the converted XLS

Record the CSV evidence before conversion

Import the result with the intended delimiter and encoding, then check dates, quotes, and leading zeros.

Test the XLS file in its receiving workflow

Recalculate in the target Excel version and inspect formulas, dates, named ranges, charts, and sheet count.

Reading CSV correctly and satisfying what XLS expects

What can fail when CSV spreadsheet format is interpreted

Formulas, formatting, charts, multiple sheets, data types, and leading zeros can disappear or be reinterpreted.

What XLS spreadsheet format cannot safely promise

Newer functions, long worksheets, charts, macros, and date systems may not fit the XLS model.

How the XLS writer handles this route

the legacy binary Excel workbook with cells, formulas, formats, and older size limits is what gets written, labeled as application/vnd.ms-excel. Whether that actually opens depends on the receiving application, not on the file extension.

When to actually choose CSV to XLS

Choose XLS when its editing, reflow, or reader support is more valuable than exact CSV structure, and test the most complex page or chapter before committing.

What changes between the CSV model and the XLS deliverable

LibreOffice opens the CSV and saves it as XLS; styles and tables carry over where XLS supports them.
Metadata handling differs between CSV and XLS; do not assume every application-specific field carries across untouched.