About Token Counter
Count GPT tokens exactly (cl100k_base and o200k_base, running locally) and estimate Claude tokens. Essential for staying within context limits and estimating API costs.
Frequently Asked Questions
What is a token in AI/LLM context?
A token is a piece of text that an AI model processes. Tokens can be words, parts of words, or characters. On average, 1 token ≈ 4 characters or ≈ 0.75 words in English.
Why does token count matter?
AI models have context limits (e.g., 4K, 8K, 128K tokens). Your prompt plus the response must fit within this limit. Token count also affects API pricing - you pay per token.
Do different models count tokens differently?
Yes, each model uses its own tokenizer. This tool counts GPT-4/3.5 (cl100k_base) and GPT-4o (o200k_base) tokens exactly. Claude has no public offline tokenizer, so the Claude figure is an estimate (characters ÷ 3.5) — exact counts require Anthropic's count_tokens API.