AI Token Counter & Prompt Cost Calculator
Paste your prompt to instantly see token count, API cost, and model comparison. 100% browser-based — your prompt never leaves your device.
Privacy: Your prompt is processed locally in your browser and is not sent to our servers.
How AI Token Counting Works
AI tokens are the fundamental units that language models use to process text. When you send a prompt to an AI model like GPT, Claude, or Gemini, the text is first broken down into tokens — which can be words, parts of words, or individual characters. For example, the word 'tokenization' might be split into 'token' and 'ization'. In Japanese, each character (kanji, hiragana, katakana) typically consumes 0.5 to 1.5 tokens depending on the model's tokenizer.
How Prompt Cost is Calculated
AI API pricing is typically measured per million tokens (per 1M tokens). The cost formula is straightforward: Input Cost = (input tokens / 1,000,000) × input price per 1M tokens, and similarly for output. Most providers charge more for output tokens than input tokens — typically 3 to 5 times more. This is because generating new text requires more computational resources than processing existing text.
Why Token Counts Differ Between Models
The same text can produce different token counts across AI models because each provider uses a different tokenization algorithm. OpenAI uses tiktoken (based on BPE), Claude uses a proprietary tokenizer, and Gemini uses SentencePiece. For instance, the word 'hello' is 1 token in GPT but might be tokenized differently in other models. CJK characters (Chinese, Japanese, Korean) are particularly variable — some tokenizers treat each character as a single token, while others combine common character pairs.
How to Reduce Prompt Cost
To reduce prompt costs, consider these strategies: remove redundant instructions, use concise language, abbreviate repeated context, leverage system prompts efficiently, and choose the right model for your task. For repetitive tasks, use few-shot examples instead of long descriptions. If your prompt includes large context, consider whether a model with a smaller context window (and lower price) would suffice. Always compare costs across models — sometimes a slightly more expensive model with better capabilities can complete the task in fewer tokens.
How to Choose the Best Model for Your Prompt
Choosing the best AI model depends on your specific needs. For cost-sensitive applications with simple tasks, models like DeepSeek or Qwen offer excellent value. For complex reasoning and coding, Claude and GPT models typically perform best. Consider not just the per-token cost, but also the model's accuracy for your task — a cheaper model that requires multiple retries may end up costing more. Use the comparison table above to find the sweet spot between cost and capability for your use case.
Frequently Asked Questions
What is an AI token?
An AI token is a unit of text that language models process. In English, one token is roughly 4 characters or 0.75 words. In Japanese, one character is approximately 0.5-1 tokens depending on the tokenizer.
How accurate is this token counter?
Our token counter uses a heuristic estimation. For OpenAI models, actual counts may vary slightly. We recommend using this tool for planning and cost estimation rather than exact billing predictions.
Does my prompt leave my browser?
No. All token counting and cost calculation happens entirely in your browser. Your prompt text is never sent to our servers or any third party.
Why do token counts differ between models?
Different AI providers use different tokenization algorithms. GPT uses tiktoken, Claude uses its own tokenizer, and Gemini uses SentencePiece. The same text can produce different token counts across these systems.
How do I estimate output token cost?
Output tokens are typically 3-5x more expensive than input tokens. Use the output ratio slider to adjust the expected output length. For chat applications, a 3x multiplier is a reasonable starting point.