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SheetTidy

Convert XLS to XLSX

Upgrade Excel 97–2003 workbooks to the modern .xlsx format, without installing anything or uploading the file.

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Drop your Excel or CSV file here

XLSX, XLSM, XLS, ODS, CSV, TSV or JSON

Your file never leaves your device

How to use this tool

  1. Step 1: Open the .xls file

    Drop the old workbook onto the tool. If it has several sheets, choose the one you want to convert.

  2. Step 2: Check the preview

    Confirm the rows, columns and characters look right. Codes with leading zeros and dates are kept as they were.

  3. Step 3: Convert

    Click Convert file. The output format is already set to Excel (.xlsx).

  4. Step 4: Download the .xlsx file

    Save the new workbook and open it in any current version of Excel, Google Sheets or LibreOffice.

Why upgrade from XLS?

The .xls format dates from Excel 97 and was replaced in 2007. Files in that format still turn up everywhere: old archives, accounting systems that never updated their export, government portals and email attachments from long ago. They mostly still open, but with limits:

  • Size. An .xls sheet holds at most 65,536 rows and 256 columns. An .xlsx sheet holds 1,048,576 rows and 16,384 columns.
  • Compatibility Mode. Excel opens .xls files in Compatibility Mode, which disables newer features and shows warnings when you save.
  • File size. XLSX files are compressed, so the same data usually takes much less space.
  • Safety. An .xls file can contain macros. Many companies block .xls attachments for that reason, while .xlsx files cannot carry macros at all.
  • Other tools. Some online services, scripts and import screens accept .xlsx and CSV only.

How to convert XLS to XLSX in Excel

Convert in place

  1. Open the .xls file in Excel. [Compatibility Mode] appears next to the file name.
  2. Choose File › Info › Convert and confirm.
  3. Excel saves an .xlsx copy, reloads it and leaves Compatibility Mode.

Save As

  1. Open the file and choose File › Save As.
  2. In Save as type, choose Excel Workbook (*.xlsx). If the file contains macros you want to keep, choose Excel Macro-Enabled Workbook (*.xlsm) instead.
  3. Click Save. The original .xls file is left as it was.

Before saving, File › Info › Check for Issues › Check Compatibility lists features that will behave differently.

Excel’s own conversion keeps formatting, formulas and charts. If you have Excel and need those, it is the best choice. Use this converter when you do not have Excel to hand, when you only need the data, or when Excel refuses to open the file properly.

Files with the wrong extension

Many websites and older business systems export a file named report.xls that is really an HTML page or tab-separated text. Excel shows the warning “The file format and extension of … don’t match” and may display it oddly. Opening it, then using Save As › Excel Workbook, usually fixes it, provided Excel can read it in the first place.

Where this converter helps

No Excel on this computer. Convert an attachment on a Chromebook, a shared computer or a phone without installing anything.

Archives of old reports. Bring a 2005 price list or an old customer export into a format that current software and colleagues can use.

Data headed for another system. Many import screens accept only .xlsx. A clean data-only workbook avoids problems with old formatting and hidden objects.

Odd exports from web portals. Files that claim to be .xls but contain HTML or text are recognised by their content and converted into a real workbook.

What the converter keeps

  • All the data on the sheet you choose: text, numbers, dates and true/false values.
  • Leading zeros. Codes stored as text, such as 001, stay as text.
  • Dates as real dates, so they still sort and filter correctly.
  • Characters in any language.

What it does not keep: formatting, column widths, formulas (they become their calculated values), charts, images, comments and macros. The new workbook has one sheet, named like the original sheet.

Checking the converted file

Open the .xlsx file and compare it with the original for a minute before you delete anything:

  1. Row count. The status bar shows the count when you select a column. It should match the original sheet.
  2. Codes and IDs. Look at a few values that start with zeros or are very long; they should be identical.
  3. Dates. Sort a date column to confirm the values are real dates rather than text.
  4. Totals. If the old file had formulas, check that one or two totals match. They are now fixed values, so add new formulas if the numbers need to keep updating.

Keep the original .xls file until you are sure nothing else in it, such as a second sheet or a chart, is still needed.

After converting

Old files often come with the habits of their time: title rows above the header, merged cells, blank spacer rows and totals mixed into the data. The Fix messy columns and Remove blank rows tools turn such a sheet into a clean list. To share the data with a system that only takes CSV, use the Excel to CSV converter instead.

Frequently asked questions

What is the difference between XLS and XLSX?

XLS is the binary format used by Excel 97 to 2003. XLSX, introduced with Excel 2007, is a compressed XML format that holds over a million rows instead of 65,536, produces smaller files and cannot contain macros, which makes it safer to share.

Is formatting kept?

No. This converter moves the data, text, numbers and dates, into a clean workbook. Colours, fonts, column widths, charts and comments are not carried over. If you need those, open the file in Excel and use File › Info › Convert instead.

What happens to formulas?

Formulas are replaced by the values they last calculated. The numbers you saw in the old file are exactly the numbers in the new one, but they no longer recalculate.

Are macros converted?

No. Macros are never run or copied. An .xlsx file cannot hold macros; if you need them, save the file as .xlsm in Excel.

Does it convert every sheet?

It converts one sheet at a time. When the workbook has several sheets with data, you choose which one, and you can repeat the process for the others.

My .xls file shows a warning in Excel that the format and extension do not match. Can this tool read it?

Often, yes. Many web systems export HTML or text files with an .xls name. The tool looks at the content rather than the name and reads them as tables.

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