FAQ
Frequently asked questions
Answers about encoding, delimiters, leading zeros, privacy, and common CSV import issues.
Why does Excel open CSV files incorrectly?
Excel applies its own rules when opening CSV files — it guesses the encoding and data types. This often causes leading zeros to disappear, dates to shift formats, or text to appear garbled. Converting to .xlsx with this tool preserves the original data structure.
How do I keep leading zeros when converting CSV to Excel?
Our tool detects fields with leading zeros (like ZIP codes and employee IDs) and writes them as text in the Excel file. They will remain as-is when you open the .xlsx in Excel.
What encoding does this tool support?
We automatically detect and support UTF-8, UTF-16, Shift-JIS, and GBK/GB18030. If auto-detection fails, you can manually select the correct encoding in the settings panel.
Can I convert Shift-JIS CSV files to Excel?
Yes. Shift-JIS is commonly used in Japanese systems. Upload your file and we will automatically detect it. If Japanese text still appears garbled, switch encoding to Shift-JIS in the settings.
Is my file stored on your server?
No. Conversion happens entirely in your browser. Your file is never sent to or stored on any server. We take privacy seriously, especially for financial and HR data.
Why are my columns split incorrectly?
This usually means the wrong delimiter was detected. Try switching between Comma, Tab, and Semicolon in the settings panel and preview the result before converting.
What is the difference between CSV and XLSX?
CSV is a plain-text format with no formatting or data type information. XLSX is a true Excel workbook that supports formulas, cell formatting, multiple sheets, frozen headers, and more.
Can I preview the file before downloading?
Yes. After uploading, a table preview shows the first 100 rows of your parsed data. You can verify that columns, encoding, and data types look correct before clicking Convert.