LLM Context Window Checker
NewEstimate whether your text fits in the context window of popular LLMs such as GPT, Claude, Gemini and Llama, with an approximate token count and percentage used.
Fit by model
Token counts are estimates (real tokenizers differ by model, typically within 10–20%). Context windows change often — GPT-6 and Claude 5.x figures come from OpenAI's and Anthropic's model docs (checked October 2026); other rows are editable defaults, so confirm them against the provider's documentation. Your text never leaves the browser.
Frequently Asked Questions
How are tokens counted?
The tool uses a fast character-based estimate (about 4 characters per token for English). Real tokenizers differ by model, so treat results as approximate.
Are the context limits exact?
They are approximate figures that change as providers release models. Verify against the provider's documentation before relying on them.
Does the output limit count against the window?
Generally yes: input and generated output share the context window, so leave headroom for the response.
Is my text uploaded?
No, the estimate runs entirely in your browser.
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