XLS to XLSX — Format Comparison & Online Converter
Fast, instant XLS to XLSX conversion. No signup required. Just drop your .xls file and get .xlsx in seconds.
Batch Settings
Some metadata may not survive
Your XLS file may contain OLE properties metadata. XLSX has limited or no support for these metadata types. Location data (GPS), camera settings, and color profiles may be stripped during conversion.
L'évolution des formats de fichiers est une réalité constante dans le monde numérique, et le passage du XLS au XLSX en est un exemple éloquent. Si le format XLS, associé aux anciennes versions de Microsoft Excel, a longtemps été un pilier pour la gestion de données, le XLSX l'a progressivement supplanté, s'imposant comme la norme moderne. Plus qu'une simple mise à jour, le format XLSX (basé sur Open XML) offre une meilleure compression, une sécurité accrue et une compatibilité étendue avec les outils actuels, tout en gérant plus efficacement les feuilles de calcul volumineuses. Cette conversion n'est donc pas qu'une question de compatibilité logicielle, mais une démarche vers une optimisation et une pérennité de vos données, essentielle pour la collaboration et l'archivage. Notre outil vous permet de réaliser cette transition en toute simplicité, garantissant l'intégrité de vos informations.
- Rapports financiers pour l'administration fiscale française
- Thèses universitaires suisses avec données complexes
- Tableaux de bord de production pour studios de design québécois
Dans la francophonie, notamment en Belgique et en Suisse, le passage au XLSX a été crucial pour la conformité avec les standards internationaux et l'interopérabilité des systèmes informatiques publics et privés. Cela a notamment facilité l'échange de documents entre différentes administrations et entreprises.
About XLS to XLSX Conversion
XLS (introduced 1987) and XLSX (introduced 2006) are both spreadsheet formats, but they differ in important ways. XLS is the legacy Excel format (pre-2007) — still encountered in business workflows. XLSX is Microsoft Excel's modern format supporting formulas, charts, and multiple sheets.
Full Name: XLS uses Microsoft Excel Legacy, while XLSX uses Microsoft Excel Spreadsheet. Compression: XLS uses None (uncompressed), while XLSX uses Lossless. Typical File Size: XLS uses 50 KB–50 MB, while XLSX uses 50 KB–50 MB.
When you convert XLS to XLSX, the goal is to upgrade to a modern format. Converting XLS to XLSX maintains high quality with CocoConvert's optimised encoder settings. Understanding these technical differences helps you choose the right format for your workflow.
Your XLS file is decoded and re-encoded as XLSX. The conversion involves 4 steps: (1) your xls file is uploaded and the format is validated, (2) the file content is decoded into its raw representation, (3) the data is re-encoded in xlsx format with optimal settings, (4) the converted file is ready for download.
CocoConvert's converter handles the entire pipeline server-side using FFmpeg, Sharp, and qpdf — battle-tested libraries used by streaming platforms and enterprise tools. Files are encrypted in transit and deleted within 24 hours.
This conversion is ideal when you You need maximum device and software compatibility. For the opposite direction, CocoConvert also supports XLSX to XLS conversion.
How to Convert XLS to XLSX
- 1
Upload .xls file
Select your XLS file by dragging it to the upload zone or using the file picker. Batch upload is available for multiple files.
- 2
Choose .xlsx
Set XLSX as the output format. The converter uses optimal settings based on the XLS→XLSX conversion profile.
- 3
Convert
The server-side engine decodes your XLS file and re-encodes it as XLSX. Processing time depends on file size and complexity.
- 4
Download result
Grab your converted .xlsx file. Multiple output files can be downloaded together.
What Happens When You Convert XLS to XLSX
Your XLS file is decoded and re-encoded as XLSX.
Your XLS file is uploaded and the format is validated
The file content is decoded into its raw representation
The data is re-encoded in XLSX format with optimal settings
The converted file is ready for download
XLS vs XLSX — Detailed Comparison
| Feature | .XLS | .XLSX |
|---|---|---|
| Full Name | Microsoft Excel Legacy | Microsoft Excel Spreadsheet |
| Compression | None (uncompressed) | Lossless |
| Typical File Size | 50 KB–50 MB | 50 KB–50 MB |
| Platform Support | Universal | Universal |
| Browser Support | none | none |
| Year Created | 1987 | 2006 |
| Open Standard | No | Yes |
Should You Convert XLS to XLSX?
When to Convert
- ✓You need maximum device and software compatibility
Common Mistakes When Converting XLS to XLSX
"XLSX will be smaller than my XLS file"
XLSX uses lossless compression, so the output file is often larger than a lossy XLS. If you need a small file, XLSX may not be the right choice.
Frequently Asked Questions
What is the difference between XLS and XLSX?
XLS is the legacy Excel format (pre-2007) — still encountered in business workflows. XLSX is Microsoft Excel's modern format supporting formulas, charts, and multiple sheets. Full Name: XLS uses Microsoft Excel Legacy, while XLSX uses Microsoft Excel Spreadsheet. Compression: XLS uses None (uncompressed), while XLSX uses Lossless. Typical File Size: XLS uses 50 KB–50 MB, while XLSX uses 50 KB–50 MB.
Does XLS to XLSX conversion affect quality?
Converting XLS to XLSX maintains high quality with CocoConvert's optimised encoder settings.
Which format has better compression, XLS or XLSX?
XLS uses none compression. XLSX uses lossless compression. The better choice depends on whether you prioritize file size or quality.
How long does XLS to XLSX conversion take?
Most conversions finish in seconds. Larger files or complex spreadsheet content may take 10–30 seconds. CocoConvert processes files in parallel for batch jobs.
Is XLS or XLSX better for long-term storage?
XLSX is better for archival since it preserves all original data.
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