AI Model Context Windows Explained: Why 1M Tokens Matters
What is Context Window?
The context window is how much text an AI model can “see” at once. It’s measured in tokens (roughly 1 token = 1 word).
Current Context Windows
| Model | Context | Notes |
|---|---|---|
| Gemini 2.5 Pro | 2M | Largest |
| Claude 4 | 200K | Excellent |
| GPT-4o | 128K | Standard |
| Gemini 2.5 Flash | 1M | Impressive |
| Claude 3.5 Sonnet | 200K | Good |
| GPT-4o Mini | 128K | Standard |
Why It Matters
Large Documents
Need to analyze a 100-page PDF? You need 200K+ context.
Long Conversations
Chatbots with memory need large context.
Codebases
Understanding entire repositories requires big context.
Research
Summarizing multiple papers needs context.
When You Don’t Need Big Context
- Simple Q&A
- Short-form content
- Quick translations
- Basic coding tasks
Cost Implications
Larger context = higher costs:
- Input tokens count toward limit
- Longer context = more expensive API calls
Our Take
128K is sufficient for most use cases. Go larger only if you have a specific need (large docs, codebases, extended conversations).