Private, local-first data tools
Convert CSV to XLSX or legacy XLS locally, preview the table first, and keep text values such as leading-zero account codes intact.
The parser runs off the main thread. Once loaded, you can search, sort, validate, repair and export without an account.
What this tool does
This converter parses the CSV as text, presents its detected structure, then creates an Excel workbook inside the same browser worker. It is a safer way to open a CSV file in Excel when delimiter, encoding or text-value guesses could damage the data. Text cells stay text by default, which protects leading zeros and long identifiers.
Local files are read by a dedicated browser worker and are not uploaded to an application server. File contents and filenames are not included in analytics events. Loading a public URL is an explicit direct request from your browser and may fail when the remote server blocks CORS.
Choose the CSV, verify its encoding, delimiter and header in the preview, then download XLSX for current Excel or XLS only for older software.
The generated workbook writes CSV values as text, so values such as 000184 remain unchanged.
Use XLSX for current Excel, Numbers and LibreOffice. XLS is provided only for compatibility with older software.
The page is online, but the file conversion itself runs locally in your browser and does not upload the CSV.
Yes. The browser converter creates the XLSX locally without an account, an upload or a paid conversion step.
Open the CSV here, confirm the detected encoding and delimiter, then save it as XLSX. Excel opens the generated workbook directly without guessing how the raw CSV columns are separated.
Yes. Choose XLSX for current Excel or select XLS only for older software. Both files are generated from the verified CSV preview in your browser.
A CSV stores values and delimiters, not fonts, colors or cell styles. Convert it to XLSX first to add Excel formatting; this tool preserves the table data but does not invent styles or formulas.