What Is an AI Token Counter?
An AI token counter measures how many tokens a piece of text consumes when processed by language models like GPT-4, Claude, or Gemini. Tokens are the fundamental units these models read and generate — and they directly determine API costs, context window usage, and response length limits.
This tool lets you paste or type text, pick a model, and instantly see an estimated token count against that model's context window, with example API costs. It helps developers, content creators, and AI power users optimize their prompts, manage context windows, and predict API expenses before making calls.
How to Use This Tool
- Paste or type your text — Enter the content you want to tokenize — a prompt (structure with our AI Prompt Template Builder), document, code snippet, or any text. The tool processes input in real time as you type.
- Select your model — Choose the model. The count is an estimate at 4.6 characters per token, the average we measured with OpenAI’s o200k and cl100k tokenizers on our own articles. Other providers’ tokenizers are not available in the browser, so treat their counts as approximate.
- Review the results — See the estimated token count, character count, word count, and estimated API cost.
- Optimize if needed — If your text exceeds a context window or budget, use the insights to trim content. Trim, re-check the estimate, and repeat.
Worked example: estimating one request
Paste a 2,000-word English article, about 12,000 characters. The tool divides by 4.6 characters per token, the average OpenAI's o200k and cl100k tokenizers gave on 25 of our own articles, and shows 2,609 tokens. Because individual articles ranged from 3.8 to 5.2 characters per token, the real count for this text is likely between 2,308 and 3,158. Code, URLs, numbers and non-English text use more tokens per character, so estimates for them run low.
At the built-in Claude 3.5 Sonnet example rate ($3 per million input tokens, $15 per million output tokens), sending that article costs about $0.0078, and asking for a 1,000-token summary adds $0.015, so output is the larger cost even though it is shorter. The model list carries 2024-25 example rates and context windows; providers change prices often, so check the provider's pricing page before budgeting, and use the provider's own token-counting endpoint when you need an exact number.
Characters-per-token figure measured by UDT in October 2026 with OpenAI's published tokenizers (o200k_base, cl100k_base) on 25 English articles; arithmetic as shown.
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