AI Tokenizer Comparison

See how the same text tokenizes — and costs — across 56 AI models. The number of tokens for identical input varies by up to 40% between providers.

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Why do tokenizers differ?

Every AI model breaks text into "tokens" — small chunks the model processes one at a time. Different providers use different tokenization algorithms. OpenAI uses BPE variants (cl100k_base, o200k_base). Google uses SentencePiece. Anthropic uses a custom v3 tokenizer (introduced with Claude Opus 4.7). For the same English sentence, these can produce token counts that differ by 30–40%, which directly affects what you pay.

Practical impact: If you're sending the same prompt to GPT-5.5 and Claude Opus 4.7, you're not paying the same price even when the per-million-token rate looks identical — because Claude consumes more tokens for the same text.