CSV and Excel Converter
How to Use
📖 Tool Introduction
Business systems export CSV while finance wants xlsx, and developers handed an xlsx need CSV to load it into a database. The usual trap in that round trip is encoding: CSV exports from domestic systems are often GBK and open as mojibake.
This tool converts both directions inside the browser. CSV to Excel supports comma, semicolon, tab and pipe delimiters, and writes plain numbers as numeric cells so you do not have to reformat afterwards. The generated xlsx is standard OOXML that opens in Office, WPS and Numbers.
Excel to CSV lists the worksheets so you can pick one, resolves shared strings correctly, and for merged cells or formulas takes the stored computed value rather than the formula text. Export can add a BOM so double-clicking in Excel shows Chinese correctly.
Files are processed locally and never uploaded, so tables containing customer lists or revenue figures are safe to convert.
✨ Features
- Bidirectional: CSV to xlsx and xlsx to CSV in one tool.
- Four delimiters supported: comma, semicolon, tab and pipe.
- GBK decoding so domestic CSV exports stop looking like garbage.
- Numbers are detected and written as numeric cells instead of quoted text.
- Handles quoted fields containing delimiters or newlines, including escaped quotes.
- Excel to CSV lists every worksheet so you can choose which to export.
- Resolves shared strings properly, so Chinese content does not become an index number.
- Optional BOM on export so Excel displays Chinese correctly on open.
- Generated xlsx is standard format, openable in Office, WPS and Numbers.
- Shows row count, column count and result size so you can verify completeness.
- Fully client-side; spreadsheet data is never uploaded.
- Drag-and-drop upload, plus copy the result to the clipboard.
🚀 How to Use
- Choose a direction: CSV to Excel, or Excel to CSV.
- For CSV to Excel: paste content or upload a file, then set the delimiter and encoding.
- Press convert to Excel and the browser downloads the generated xlsx.
- For Excel to CSV: upload the xlsx, then pick a worksheet from the dropdown after parsing.
- Press export CSV, then copy or download the result; tick BOM for Chinese content.
⚠️ Notes
- Export is UTF-8 only：Browsers ship no GBK encoder, so exported CSV is always UTF-8. Convert to GBK using Save As in Excel if required.
- Legacy .xls is not supported：Only .xlsx is handled. Excel 97-2003 .xls files must be saved as the newer format first.
- Formulas yield stored values：Cells containing formulas are read as the last saved computed value, not the formula source.
- Merged cells keep one value：Only the top-left cell of a merged range carries a value; the rest are empty. That is how xlsx stores them.
- Very large sheets are slow：Parsing or generating tens of thousands of rows can freeze the tab briefly; split the work into batches.
- Dates may appear as numbers：xlsx stores dates as serial numbers, so some exports show digits. Apply a date format in Excel afterwards.
Encoding and formatting notes
- Character encoding: choose UTF-8 for modern exports and GBK or Big5 when the file comes from legacy Chinese Windows software. Picking the wrong one produces mojibake rather than an error, so preview the first rows first.
- Delimiters: comma, semicolon and tab are detected automatically, and you can pin one manually when a file mixes them.
Privacy and compatibility
- Nothing is uploaded: parsing and spreadsheet generation run entirely in your browser, so financial and customer data stays on your device.
- Size limits: very large sheets are processed in chunks; if the browser runs low on memory, split the file and repeat.