Sheet ReserveSpreadsheets worth keeping.

Free tools · no account

Free spreadsheet tools that run in your browser

Five converters for the awkward moments between formats: CSV to Excel and back, CSV to JSON, a delimiter fixer for files Excel opens in a single column, and a way to keep the zeros in ZIP codes and IDs. Your file is read by your own browser and written on your device. Nothing is uploaded. Not sure where to start? Begin with CSV to XLSX.

  • CSV to XLSX

    CSV in · XLSX outTurn a CSV, TSV or semicolon-separated file into an Excel .xlsx workbook in your browser. Numbers stay numbers, leading zeros stay text, nothing is uploaded.

  • XLSX to CSV

    XLSX in · CSV or ZIP outConvert an Excel .xlsx workbook to CSV in your browser. Each sheet becomes its own CSV, formulas are written as their last result, and nothing is uploaded.

  • CSV to JSON

    CSV in · JSON outConvert CSV to JSON in your browser: an array of objects or of arrays, numbers typed, no sign-up and no upload. Copy the preview or download the .json file.

  • Delimiter converter

    CSV in · CSV outChange a CSV delimiter between comma, semicolon, tab and pipe, and fix the file Excel opens in one column. Runs in your browser; nothing is uploaded.

  • Leading zeros

    CSV in · XLSX outStop Excel dropping the zeros in ZIP codes, account numbers and IDs. Convert a CSV to .xlsx with the columns you choose written as text. Free, in your browser.

Built like the rest of the site

The sheet preview you see in each tool is the same spreadsheet grid used on every Sheet Reserve page, and the files are written by the same browser-side writers that produce the library downloads. No conversion server is involved, because there is none to be wrong about your data.

How the conversion works

Files and open data: formats, datasets, guides

Questions

Are these tools really free?

Yes. All five run in your browser with no account, no sign-up and no payment. Sheet Reserve also sells a library of spreadsheet templates and datasets; the tools are separate from it.

Do I have to upload my file?

No. Your file is read by your own browser and the result is written on your device. No file is sent to Sheet Reserve or to anyone else.

Do the tools work offline?

Once the page and its scripts have loaded they keep working, but the first visit needs a connection to fetch them. There is no install.

Which spreadsheet programs accept the results?

XLSX results open in Excel, Google Sheets, LibreOffice Calc and Apple Numbers. CSV results open in any spreadsheet program and in most programming languages.