SXC to XLS Converter

Convert SXC to XLS online for free. Fast, secure, and high-quality conversion with no sign-up or software required.

Free to useNo file stored beyond 1 hourEncrypted over TLS 1.2/1.3No watermarks

or drag and drop files here

Maximum file size is 1GB

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How it works

Three steps to your converted file

Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.

Upload your file

Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.

Choose an output format

Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.

Convert & download

Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.

What is an SXC file?

The SXC (StarOffice Calc) format is a legacy XML-based spreadsheet file developed by Sun Microsystems for the StarOffice suite (versions 5.2 through 7.0). It acts as the technical predecessor to the modern OpenDocument (ODS) standard. The format utilizes ZIP compression to encapsulate XML data describing cell values, formulas, and formatting. While largely obsolete following the standardization of ODF in 2005, SXC remains significant in the history of open-source office software development.

How to open an SXC file

Modern native OS support for SXC is non-existent without third-party tools. The most reliable software for opening SXC files is LibreOffice Calc or Apache OpenOffice, both of which maintain backward compatibility with legacy StarOffice formats. Microsoft Excel does not support SXC natively and requires file conversion prior to access.

SXC Technical Info

Full Name: StarOffice Calc Spreadsheet
Developed By: Sun Microsystems
Initial Release: 2000
MIME Type: application/vnd.sun.xml.calc

What is an XLS file?

The XLS format utilizes the Binary Interchange File Format (BIFF) scheme, serving as the default spreadsheet standard for Microsoft Excel from versions 2.0 through 2003. Encapsulated within the Object Linking and Embedding (OLE) Compound File Binary Format (CFBF), XLS files store data in binary streams rather than XML. This proprietary structure supports formulas, Visual Basic for Applications (VBA) macros, and charts but lacks the compression efficiency and corruption resilience of the newer XML-based standards.

How to open an XLS file

Microsoft Excel remains the primary software for full fidelity access to XLS files. On Windows and macOS, the operating system associates these files with the Office suite if installed. Alternatively, open-source solutions like LibreOffice Calc and Gnumeric provide robust reverse-engineered support for reading and editing XLS binaries on Linux and other platforms without requiring Microsoft licenses.

XLS Technical Info

Full Name: Excel Binary File Format
Developed By: Microsoft
Initial Release: 1987
MIME Type: application/vnd.ms-excel

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Why RunConvert

The fastest way to convert any file

Purpose-built for speed, privacy, and breadth of format support.

Convert SXC to XLS in seconds

Every SXC to XLS conversion runs on our servers, so your device stays fast and the output quality stays intact.

Fast, cloud-powered

No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.

Secure & private

Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.

Free - no account needed

Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.

Developer API

Convert SXC to XLS via API

Automate SXC to XLS conversions in three steps: create a job, upload your file, then poll for the result.

# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tag": "sxc-to-xls",
    "tasks": {
      "upload-file": {
        "operation": "import/upload"
      },
      "convert": {
        "operation": "convert",
        "input": "upload-file",
        "output_format": "xls"
      },
      "export-result": {
        "operation": "export/url",
        "input": "convert"
      }
    }
  }'

# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.sxc

# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
  -H "Authorization: Bearer YOUR_API_KEY"

Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.