🤖 AI Token Counter
Count tokens for GPT-3.5, GPT-4, and Claude models using the exact tokenizer. Estimate API costs before sending requests. Free online LLM token counter — no signup needed.
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Tokens
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Characters
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Words
$0.00
Input price
$0.00
Output price
0%
Context Used
Token count is an approximation (4 chars ≈ 1 token). Pricing per 1M tokens from public APIs.
How to Use
1
Paste or type your text
Enter any text — a system prompt, document, or message. Token count updates live as you type.
2
Select your AI model
Choose GPT-4, Claude 3, Llama 3, or Gemini Pro. Pricing and tokenization differ per model.
3
Read the estimate
See tokens, characters, word count, and estimated API cost for input and output tokens.
Frequently Asked Questions
What is a token in AI models?
A token is the basic unit of text that AI language models process. Tokens are roughly 4 characters or ¾ of a word in English. "Hello world" is about 2 tokens. Tokenization varies by model — GPT uses BPE (Byte Pair Encoding), while Claude and Llama have their own tokenizers.
How accurate is this token counter?
This tool uses standard approximation rules: ~4 characters per token for English text. For exact counts, use the official tokenizer. Accuracy is typically within 5% for English content. Non-English text (especially CJK characters) may use more tokens per character.
Why do different models have different token counts?
Each AI model uses a different tokenizer trained on different data. GPT-4 uses cl100k_base, Claude uses its own SentencePiece-based tokenizer, and Llama uses a different vocabulary. The same text can produce different token counts across models.
How is API cost calculated?
API providers charge per 1,000 or 1,000,000 tokens. The cost shown is an estimate based on current published pricing. Input and output tokens are often priced differently — output (completion) tokens usually cost 2-3x more than input tokens.
Is my text sent to any AI model or server?
No. Token counting is done entirely in your browser using JavaScript. Your text is never sent to any AI model, API, or server.
完整指南：AI Token计数器
什么是Token？
大型语言模型将文本分割为"token"（约4个字符或3/4个英文单词）。上下文限制和API价格按token计算。知道prompt的精确token数可防止超出限制并帮助估算成本。
如何使用
- 粘贴文本或prompt。
- 选择模型：GPT-4、Claude、Llama——每个模型使用不同的分词器。
- Token数和估算成本即时显示。
专业技巧
- 英文比其他语言更节省token——相同内容的中文可能使用2-3倍的token。
- 系统提示词也算token——保持简洁以降低成本。
- 长上下文考虑使用RAG而不是发送整个上下文。