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OpenAI vs Llama tokenizers: why the same text produces different token counts

This counter provides text counts for supported OpenAI encodings and Llama 3. Llama 4, Claude, and Gemini are estimates. Use the target tokenizer or provider API for production budgets and full chat formatting.

A sentence that costs 50 tokens on GPT-5 might cost 55 tokens on Llama 4 or 48 on Claude. The differences come from the tokenizer's vocabulary, its merge rules, and how it handles whitespace, capitalization, and non-English text. Even among OpenAI models, GPT-5 (o200k_base) and GPT-4 (cl100k_base) use different tokenizers with different counts.

By TechCompare · Updated

Knowledge area
Model Comparison
Tokenization across model families
Topic focus
OpenAI vs Llama tokenizer
tokenizer-comparison

How this is calculated

OpenAI encodings and Meta tokenizer generations have different vocabularies and merge rules. Llama 3 uses its own BPE tokenizer, while Llama 4 has a distinct tokenizer with a 202,048-entry model vocabulary. Vocabulary size alone cannot establish which model uses fewer tokens for a particular prompt. Compare the actual target tokenizers.

Verdict

Do not substitute the Llama 3 tokenizer for Llama 4. They use different vocabularies and can segment the same text differently. This page labels Llama 4 as an estimate until its own tokenizer is supported. Benchmark real prompts instead of assuming that a larger vocabulary always reduces cost.

More Tokens scenarios

What are tokens
A token is the atomic unit of text that a language model processes.
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Token limits by model
A model context limit is a token budget, but providers may publish separate input and output limits.
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Prompt optimization
Prompt optimization aims to get the same or better results with fewer input tokens.
View details ➜

Frequently asked questions

Why does the same text tokenize differently on GPT and Llama?
Each tokenizer has its own vocabulary and merge rules. Llama 3 and Llama 4 also differ from each other. Whitespace, capitalization, code, and language all affect the resulting count.
Which is more token-efficient, GPT-5 or Llama 4?
It depends on the text. Compare the target tokenizers on representative prompts. The Llama 4 option here is a rough estimate, so it cannot establish an exact efficiency ranking.
Does tokenizer efficiency change my API bill?
Directly. A model that turns your prompt into 10% fewer tokens bills you 10% less for the same requests, which at GPT-5 pricing and high volume is hundreds of dollars a month. Benchmark your actual prompts against each candidate model's tokenizer before choosing on per-token price alone.