LLM context window comparator

Compare context windows across LLMs and see whether a document or token budget fits before you send it to a model.

How to use this tool

  1. Select two or more models to compare.
  2. Paste a document or enter its token count.
  3. Check the fit result and the share of each model’s context window used.

Worked example: Example: a 120,000-token document fits inside a 200,000-token context window, leaving about 80,000 tokens for instructions and output.

Choose at least two models

Keep two selected so the comparison remains meaningful.

Document size
Document estimate0 tokens0 standard pages

GPT-5.4

openai · 1.05M context

Fits

1,050,000 tokens remain for instructions and output.

Claude Sonnet 4.6

anthropic · 1M context

Fits

1,000,000 tokens remain for instructions and output.

Gemini 3.1 Pro Preview

gemini · 1M context

Fits

1,000,000 tokens remain for instructions and output.

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