CSV to Excel Converter – Convert CSV Online (Free Tool)

Convert CSV files to real Microsoft Excel workbooks (.xlsx) right in your browser — no upload, no account, no row limits beyond what fits in memory. The converter follows RFC 4180 quoting rules, auto-detects delimiters, and infers numeric/date/boolean column types so Excel opens the result as a properly typed spreadsheet instead of a wall of text.

• Stable behavior across visits — no surprise version drift
• Your data stays private — all processing happens locally in the browser
• No telemetry, no tracking pixels, no third-party scripts
• Built on SheetJS / pdf.js / OOXML — the same libraries used by serious desktop tools
• Auto-detects encoding (UTF-8, Shift_JIS, GBK, Vietnamese) for CSV imports

1. Upload or paste your CSV data
2. Preview the data in the table
3. Click "Convert to Excel" button
4. Download the .xlsx file

• Importing analytics exports (Stripe, Google Analytics, Shopify) into Excel for reporting
• Sharing data with non-technical teammates who only have Excel
• Preparing CSV downloads for upload into accounting software that requires .xlsx
• Quickly inspecting large CSVs in Excel without breaking column types
• Converting database dumps for offline analysis

Leading zeros disappear from ID columns (e.g. 00123 → 123)

Force the column to text in the column-type override before converting. CSV is untyped, but Excel auto-coerces numbers — text mode keeps every character literal.

Rows look misaligned after conversion

The delimiter was probably wrong — pick the correct one (comma/semicolon/tab/pipe). Also check that quoted fields use straight " and not curly " " quotes.

Date column shows as a number

Excel stored it as a serial number — format the column as Date in Excel, or pre-format the CSV dates as ISO 8601 (YYYY-MM-DD) so the converter recognises them.