AI Token Counter — GPT, Claude & Gemini
≈ estimate · GPT-4 / Claude / Gemini compatible
What is AI Token Counter — GPT, Claude & Gemini
A token counter estimates how many tokens a piece of text uses when processed by large language models (LLMs) like GPT-4, Claude, or Gemini. Tokens are the fundamental unit AI models use to read text — roughly 1 token per 4 characters, or about 0.75 tokens per word in English. Knowing your token count is essential when writing prompts, building RAG pipelines, or staying within context window limits to avoid truncation and control API costs.
How to use
- Paste or type any text into the input field — prompts, documents, code, or conversation history.
- Read the token count instantly in the blue card at the top.
- Check the context usage bars to see what percentage of GPT-4 (128k) and Claude (200k) context windows your text fills.
- Use the character and word counts for additional reference.
When to use it
Building a RAG chatbot and worried a retrieved chunk plus your system prompt won't fit GPT-4's 128k context window? Paste the combined text and you see it uses 4,200 tokens (3.3% of the limit), so you know there's plenty of room for the model's response before you ever hit the API. Handy for trimming prompts, sizing chunks, and estimating cost per call.
Frequently asked questions
How accurate is this token counter?
This tool uses a BPE-compatible heuristic (approximately 4 characters per token for English) and is accurate within ±10% for typical English text. For exact counts, use the official tiktoken library from OpenAI. Non-English scripts, code, and heavily punctuated text may vary more.
What is a token in AI models?
A token is a chunk of text that an AI model processes as a unit. It can be a whole word, part of a word, or a single character depending on the word. Common words like 'the' are one token; longer or unusual words may be split into multiple tokens. Most LLMs bill API usage by tokens consumed.
What is a context window?
A context window is the maximum number of tokens a model can process in a single request — including your prompt, any conversation history, retrieved documents, and the model's response. GPT-4 Turbo supports 128k tokens; Claude 3 supports up to 200k. Exceeding this limit causes the model to truncate older content.
Why do different models have different token counts for the same text?
Each model uses its own tokenizer (vocabulary of BPE tokens). OpenAI models use tiktoken; Claude uses Anthropic's internal tokenizer; Gemini uses SentencePiece. The differences are typically small (5–15%) for English text but can be larger for other languages.
Is my text sent to a server?
No. All counting happens in your browser with JavaScript. Your text never leaves your device.
Can I share this tool with my inputs pre-filled?
Yes. The URL updates automatically as you type. Copy it from the address bar or use the Share button — anyone who opens the link will see your exact inputs ready to go.
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