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Convert XLS to XLSX

Turn your XLS files into Excel workbooks in seconds. Conversion happens in your browser, so your files are never uploaded to a server.

  • Files never uploaded
  • Free, no sign-up
  • No queue

or drop them here. You can also paste an image (Ctrl+V).

Free · No sign-up · No upload

How to convert XLS to XLSX

  1. 01

    Add your XLS files

    Click “Choose XLS files” or drop them on the page. You can add several at once.

  2. 02

    Check the XLSX format

    XLSX is already selected. Sheets, numbers, dates and common formulas are carried over; a formula that cannot be translated keeps its last value, and you are told.

  3. 03

    Convert and download

    Click “Convert”, then download your XLSX file. With several files, grab everything at once as a ZIP.

XLS to XLSX: what to know

XLS is the binary format of Excel 97-2003, still found in exports from banking or accounting software and from suppliers running older systems. Moving to XLSX lifts its limits, 65,536 rows and 256 columns per sheet against 1,048,576 rows and 16,384 columns, and satisfies platforms that reject the old format. Every sheet is carried over under the same name, and hidden sheets, rows and columns stay hidden.

Formulas are carried over with their last result, and so are defined names, including those limited to one sheet; an array formula or a reference to several sheets at once keeps only its value, and a message gives their number. The file is read right in your browser, with no external module. An .xls file that is really a web page is read too, with the line breaks in its cells and its hidden rows and columns, and so is an Excel 2003 XML workbook, with the formats of its codes and durations (01000, 41:30:00). A password-protected workbook is refused, as are formats older than Excel 5; Excel 5/95 files keep the values of their formulas. Otherwise, this is a conversion of the data, not a facsimile: merged cells and links are carried over, but formatting is not, nor are charts, images and comments, which a message points out. Numbers lose their display format, except for the leading zeros of codes such as 01000, which stay on display, and fractions, scientific notation, durations in minutes or seconds, negatives in brackets and formats with a colour or a condition, whose format is kept: 25% becomes 0.25, as the message also says, and column widths are recalculated to fit the content. If the workbook must stay identical, open it in Excel instead and use Save As to store it in .xlsx format.

XLS vs XLSX: what’s the difference?

XLSMicrosoft Excel 97–2003

Excel’s old binary format (versions 97 to 2003). It still turns up in archives and older software; as XLSX it becomes lighter and more compatible.

XLSXMicrosoft Excel (Office Open XML)

The Microsoft Excel workbook format since 2007. It holds one or more sheets with their numbers, dates, text and formulas.

XLS to XLSX: frequently asked questions

Are the macros in my XLS file kept in the XLSX?

No. An XLSX file can’t contain VBA macros; that takes an XLSM file. The conversion keeps only the content of the sheets, formulas included. If your workbook relies on macros, keep the original XLS, or open it in Excel and save it in .xlsm format.

Why are my dates shown as 2024-03-15 after converting?

The dates are still real dates that you can sort and use in calculations; only their display format changes, to the international year-month-day order (a date written in words, such as 15-Mar-24, keeps its format). To get 15/03/2024 back, select the column, open Format Cells and choose the date format you prefer.

Are my XLS files uploaded to the internet?

No. The file is read and converted by your browser, on your device. Nothing is sent to a server, and nothing is kept after you close the page.

Does converting XLS to XLSX reduce quality?

Values, numbers, dates, times and sheets are carried over, and so are common formulas with their last result and defined names. A formula specific to one program (or a reference to several sheets at once) keeps only its last value, and the conversion says so. Formatting (colours, column widths) is not carried over, but a number keeps the decimals its format shows (12.50). An XLSX or ODS workbook with a damaged essential part (a sheet, its texts, its styles) is refused, with the name of that part, and a date that does not exist (a 31 February) is kept as written, as text, which a message points out.

How many XLS files can I convert?

As many as you like, for free and without signing up. Add them all, then download the results one by one or in a single ZIP. The maximum size depends on your device and browser, with a few caps that protect its memory (for example 20,000 files per archive or 5 million filled cells per workbook: see the home page FAQ); a file over one of them is not converted, and a message says so.

Does it work on iPhone and Android?

Formatomat is designed for recent browsers on computers, iPhone and Android, with no app to install. A conversion the browser cannot do (a format it cannot read or write) is refused with a message that says so.