What is a XLSX file?
XLSX — Microsoft Excel (Office Open XML)
Use the format XLSX
A concrete example
A list of products can be exported in CSV for import. A table intended for reading or printing can be provided in PDF.
What does the conversion change?
CSV and TXT do not preserve the entire workbook structure: styles, graphics, and formulas do not remain as calculation objects. Check which sheet is exported. PDF locks a paginated layout.
Useful checks
Check the separators, decimals, dates, and leading zeros. Before exporting in PDF, check the print areas and the columns that may be cut off.
Choose a conversion
Keep the original and open the result in the software or on the device that will need to use it.
Your questions about this format
How to recognize a scanned PDF and use the OCR?
Open the PDF and try to select then copy a sentence in a text editor. If only an image is selected, the document may be a scan without recognized text. A PDF protection may also prevent copying. In ConvertLab, add the PDF, then choose "Text Recognition (OCR)" in "PDF Action" during the preparation step. This NoLimit option produces a PDF with a text layer. Download it, then, if you want a Word document, use this result for a conversion to DOCX. Proofread the names and numbers: a blurry scan can cause errors.
Will the layout be preserved in Word?
A PDF describes pages, while Word rearranges text and objects. Columns, complex tables, and fonts may therefore change. For a document to be edited, choose DOCX and plan for a review. To maintain a page appearance, choose a JPEG or PNG output; the text in these images will not be directly editable.
Why is my compressed PDF so large?
An already optimized file can decrease very little, or even increase. The NoLimit compression option does not promise a reduction percentage. Compare the sizes indicated after processing and keep the file that suits you best without overwriting your original.
How to convert a presentation into a Word document?
Add your PPTX and choose DOCX. The "Editable Text" mode makes it easier to reuse the content; the "Slides as Images" mode preserves a visual representation of the slides, but their text cannot be edited like a Word paragraph. Choose the mode before starting the conversion.
What is it?
XLSX has been Excel's spreadsheet format since 2007. It holds far more than numbers: formulas, conditional formatting, charts, multiple sheets, named ranges, and pivot tables.
That's the key difference with CSV: a CSV file stores only values, while XLSX stores an entire workbook, calculation logic included. Technically, a XLSX file is an archive of XML files.
History & origin
Excel has dominated the spreadsheet market since the late 1980s, relying on the binary .xls format for nearly twenty years.
XLSX arrived with Office 2007, as part of Office Open XML (ISO/IEC 29500). It also did away with its predecessor's limits: up to 1,048,576 rows and 16,384 columns per sheet, compared to just 65,536 rows before.
Why it is useful
It preserves the workbook's intelligence: change one cell, and everything recalculates. No flat exchange format can do that.
It handles multiple sheets, charts, and formatting, and remains readable in LibreOffice Calc, Google Sheets, and Numbers.
Limits & drawbacks
It's cumbersome to work with for large datasets, where a CSV file can be processed by a script in a matter of seconds.
Two well-known pitfalls: dates, which Excel is happy to reinterpret its own way, and numeric identifiers starting with a zero, which it silently strips. Lastly, a XLSX file cannot contain macros—that's what the .xlsm extension is for.
Practical tips
To share data meant for machine processing, convert to CSV: you'll lose formulas and formatting, but you'll get a lightweight, universal file. Remember to check the delimiter and encoding after conversion.
To send a table meant to be read—a budget, a report—PDF is the better choice: the layout stays fixed, and no one will accidentally alter your figures.
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