The maximum length of prompt that Claude can process is its context window. The context window for paid Claude plans, Claude for Work (Team and Enterprise) plans, and our API is currently 200k+ tokens (about 500 pages of text or 100 images) for all models and plans, with two exceptions:
Users on Enterprise plans can leverage an enhanced 500K context window when chatting with Claude Sonnet 4.
API users can access a 1M context window when using Sonnet 4.
The context window and usage limit of free Claude plans can vary depending on current demand. More information on these limits can be found here: About Free Claude Usage.