SheetCompareCSV to Excel Converter
Turn a CSV file into a clean .xlsx workbook in your browser. No signup, no upload, no data leaves your device.
Drop your file here
Accepts CSV · Runs in your browser. Your file never leaves your device.
CSV is a great interchange format, but it's a poor home for spreadsheets. Open a CSV in Excel and you'll lose number formatting, watch dates morph into Julian-style integers, see leading zeros stripped from ZIP codes and SKUs, and end up staring at strange Asian glyphs where accented characters used to be. Converting to .xlsx solves most of that — Excel can store types, encoding, and formatting properly.
This tool reads your CSV with the same parser SheetCompare uses for its diff product, then writes a single-sheet .xlsx workbook you can open directly in Excel, Google Sheets, Numbers, or any other spreadsheet app. Everything happens client-side. We don't have a server that sees your file.
Three steps, no signup
- 1
Drop your CSV
Drag a .csv file into the box above, or click to pick one from your computer.
- 2
We parse and convert
Headers are detected automatically. Values are written into a single Excel sheet with their types preserved where possible.
- 3
Download the .xlsx
A properly formatted Excel workbook is ready instantly. Open it in Excel, Google Sheets, or Numbers — no further cleanup required.
Frequently asked questions
- Why not just open the CSV in Excel directly?
- You can, but Excel's built-in CSV import is famously aggressive. It strips leading zeros, reformats dates based on your locale, drops accented characters when the encoding isn't UTF-8 with a BOM, and turns long numeric strings (like account numbers) into scientific notation. Saving as .xlsx ahead of time, with a parser that respects the source, avoids most of those traps.
- Will my dates stay as dates?
- Cells that look like dates are passed through as strings unless they're already typed as dates in the source. We deliberately don't guess at formats — that's the bug, not the feature, in most CSV importers. If you need a specific date format in the output, format the column in Excel after opening the file.
- What happens to leading zeros and long numbers?
- We preserve the original string when a value can't be safely converted without losing information. Things like "00123" or 16-digit credit card numbers come through intact rather than getting reformatted as numbers. You can change the column type in Excel if you want it numeric.
- Does it handle UTF-8 and other encodings?
- Yes. Files are read as UTF-8, which covers the overwhelming majority of modern CSVs including non-Latin scripts, emoji, and accented characters. Older Windows-1252 files that were mis-saved may show replacement characters — re-export them as UTF-8 from the source if you can.
- What about multi-sheet output?
- A single CSV becomes a single sheet in the workbook. If you need multiple sheets, convert each CSV individually and combine them in Excel, or use SheetCompare's full app to work with multi-sheet workbooks directly.
- Is there a file size limit?
- Because everything runs in your browser, the practical limit depends on your machine's memory. Files up to a few hundred thousand rows convert in seconds on a modern laptop. Very large CSVs may want a desktop tool.
- Is my data safe?
- Yes. The conversion happens entirely in your browser using JavaScript. No upload, no server, no logs. We literally cannot see your file — close the tab and it's gone.