AI Token Counter
Count tokens for GPT, Claude, and other LLMs online
About AI Token Counter
Count tokens for OpenAI GPT and Anthropic Claude models instantly. Estimate how many tokens your prompt, system message, or document uses before sending it to an API. Supports approximate token counts for GPT-4, GPT-3.5, Claude 3, and other popular LLMs. Essential for staying within context window limits and optimizing API costs.
Use Cases
- Estimating prompt length before sending to OpenAI or Claude API
- Checking if your text fits within a model's context window
- Optimizing prompts to reduce token usage and API costs
- Comparing token counts across different model tokenizers
Frequently Asked Questions
What is a token?
A token is a chunk of text that language models process. It can be a word, part of a word, or punctuation. On average, 1 token is about 4 characters or 0.75 words in English.
How accurate is this counter?
This tool uses a character-based estimation formula that closely approximates real tokenizer output. For exact counts, use the official tiktoken (OpenAI) or Anthropic tokenizer libraries.
Do different models count tokens differently?
Yes. GPT-4 and Claude use different tokenizers, so the same text may produce slightly different token counts. This tool shows estimates for multiple models.
What are context window limits?
Each model has a maximum number of tokens it can process (input + output). For example, GPT-4 Turbo supports 128K tokens and Claude 3 Opus supports 200K tokens.