What is context window in LLMs?

Updated May 16, 2026

Short answer

Context window is the maximum number of tokens an LLM can process at once.

Deep explanation

The context window defines how much input and history a model can consider. Larger context windows allow better reasoning over long documents but increase compute cost.

Real-world example

Analyzing long legal contracts in one pass.

Common mistakes

Assuming infinite memory in LLMs.

Follow-up questions

What happens if context exceeds limit?
Why larger context is expensive?

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