LLM File Format Support
An AI model is only as intelligent as the data you give it. Before you invest in an AI solution, ask yourself: can it understand the file formats your business runs on every day?
The ability to accurately read a .docx proposal, extract data from a .pdf invoice, or parse a .xlsx financial report is not a minor technical detail—it is the core of a successful implementation. Choosing a model that struggles with your primary document types can lead to frustrating errors, inaccurate results, and a failed project.
This practical guide provides a clear comparison of how today's leading Large Language Models (LLMs)—ChatGPT, Claude, DeepSeek, and Gemini—handle the file formats that matter most, helping you make a more informed strategic choice.
Standard Business Documents: The Everyday Essentials
This category covers the bedrock of business communication: text documents, PDFs, and presentations.
- Simple Text & Word Documents (.txt, .docx): All major models handle plain text flawlessly. However, for Word documents, Gemini and DeepSeek show stronger performance in interpreting not just the text but also understanding the layout, while ChatGPT and Claude can sometimes struggle with complex formatting, tables, or embedded images.
- PDFs (.pdf): This is a critical differentiator. While most models can extract text from simple PDFs, Gemini's native vision capabilities allow it to "see" a PDF like a human, understanding complex layouts, charts, and images within the document. DeepSeek also shows strong PDF support, whereas ChatGPT and Claude are more prone to errors with non-standard formats.
Business Takeaway: If your workflows rely heavily on complex PDFs (like scanned invoices, architectural plans, or graphical reports), Gemini's superior processing gives it a significant advantage.
Structured Data: The Language of Your Numbers
The ability to natively understand structured data formats like spreadsheets and databases is crucial for any serious data analysis or business intelligence task.
- Spreadsheets (.csv, .xls, .xlsx): Gemini is the undisputed leader here, being the only model in this comparison with full, native support for Excel files (.xlsx). All models can handle the simpler .csv (Comma-Separated Values) format, but Gemini's ability to parse complex, multi-sheet Excel workbooks opens up powerful possibilities for financial modelling and data analysis without data conversion.
- Data & Configuration Files (.json, .xml, .yaml): ChatGPT and Claude have excellent support for these formats, which are critical for developers and for integrating AI into technical workflows. Gemini shows only partial support, and DeepSeek's capabilities are more limited, making them less ideal for tasks requiring deep understanding of system configurations or API responses.
Business Takeaway: For any AI project involving financial analysis, sales forecasting, or business intelligence directly from Excel files, Gemini is the clear choice. For projects that involve integrating with other software APIs, ChatGPT and Claude are more robust.
Developer & Academic Formats
For technical documentation, software development, and academic research, specific formats are essential.
- Code & Markup (.md, .html): All four models show strong support for Markdown and HTML, which are fundamental for understanding software documentation and web content.
- Academic Formatting (.tex): ChatGPT and Claude excel at interpreting LaTeX, the standard for scientific and academic papers, making them invaluable tools for researchers and academics.
Business Takeaway: If your business operates in a technical or scientific field, the strong LaTeX support from ChatGPT and Claude can be a deciding factor.
At-a-Glance Comparison Table
✅ Full support (can read and interpret formatting)
⚠️ Partial support (extracts text but may struggle with advanced formatting)
❌ No support
🔍 Can read metadata only
Format | ChatGPT | Claude | DeepSeek | Gemini |
Plain Text (.txt) | ✅ | ✅ | ✅ | ✅ |
Markdown (.md) | ✅ | ✅ | ✅ | ⚠️ |
Rich Text Format (.rtf) | ✅ | ✅ | ❌ | ❌ |
CSV (.csv) | ✅ | ✅ | ✅ | ✅ |
JSON (.json) | ✅ | ✅ | ✅ | ⚠️ |
XML (.xml) | ✅ | ✅ | ❌ | ⚠️ |
YAML (.yaml, .yml) | ✅ | ✅ | ✅ | ❌ |
HTML (.html) | ✅ | ✅ | ✅ | ⚠️ |
LaTeX (.tex) | ✅ | ✅ | ❌ | ❌ |
PDF (.pdf) | ⚠️ | ⚠️ | ✅ | ✅ |
Word Documents (.docx) | ⚠️ | ⚠️ | ✅ | ✅ |
Excel Spreadsheets (.xls, .xlsx) | ❌ | ❌ | ❌ | ✅ |
ZIP Files | 🔍 | 🔍 | ❌ | 🔍 |
Conclusion: Choose the AI That Speaks Your Company's Language
There is no one-size-fits-all answer. The "best" AI model is the one that is most fluent in the specific file formats your business relies on.
- Choose Gemini if your world revolves around complex PDFs and Excel spreadsheets.
- Choose ChatGPT or Claude if you need to process highly technical or academic documents and integrate with other software APIs.
- Choose DeepSeek if you need a strong, flexible base for handling standard document formats within a custom-built solution.
Making the right choice from the outset prevents costly rework and ensures your AI investment delivers tangible results.
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