# Prompt Token Counter — Model Guides, Definitions, Conversions For the full tool, see: [https://capytoolkit.com/tools/developer/token-counter/](https://capytoolkit.com/tools/developer/token-counter/) ## AI Models [Claude Fable 5 Token Counter](https://capytoolkit.com/tools/developer/token-counter/claude-fable-5-token-count/): Count Claude Fable 5 tokens in your browser. Exact count via the Anthropic tokenizer. See 1M context window usage and cost at $10/M input tokens. [GPT-5.6 Sol Token Counter](https://capytoolkit.com/tools/developer/token-counter/gpt-56-sol-token-count/): Count GPT-5.6 Sol tokens instantly in your browser. See exact token count, context window usage, and input cost at $5/M tokens. Runs locally, nothing uploaded. [Claude Opus 5 Token Counter](https://capytoolkit.com/tools/developer/token-counter/claude-opus-5-token-count/): Count Claude Opus 5 tokens in your browser. See exact token count via the Anthropic tokenizer, 1M context window usage, and cost at $5/M input. [Claude Sonnet 5 Token Counter](https://capytoolkit.com/tools/developer/token-counter/claude-sonnet-5-token-count/): Count Claude Sonnet 5 tokens in your browser. Estimate prompt costs with Sonnet 5 pricing and a 1M-token context window. [Claude Haiku 4.5 Token Counter](https://capytoolkit.com/tools/developer/token-counter/claude-haiku-45-token-count/): Count Claude Haiku 4.5 tokens in your browser. Estimate pricing and context usage for claude-haiku-4-5 prompts before you send. [Gemini 3.1 Pro Token Counter](https://capytoolkit.com/tools/developer/token-counter/gemini-31-pro-token-count/): Estimate Gemini 3.1 Pro tokens in your browser. Check 1M-context usage and tiered Gemini Developer API pricing before you send. [Gemini 3.5 Flash-Lite Token Counter](https://capytoolkit.com/tools/developer/token-counter/gemini-35-flash-lite-token-count/): Estimate Gemini 3.5 Flash-Lite tokens in your browser. Approximate count using character length. See 1M context window usage and low $0.30/M input pricing. [DeepSeek V4 Pro Token Counter](https://capytoolkit.com/tools/developer/token-counter/deepseek-v4-pro-token-count/): Estimate DeepSeek V4 Pro tokens in your browser. Approximate count via cl100k_base. See 1M context window usage and cost at $0.435/M cache-miss input. [Kimi K3 Token Counter](https://capytoolkit.com/tools/developer/token-counter/kimi-k3-token-count/): Estimate Kimi K3 tokens in your browser. Approximate count via character formula. See context window usage and cost per million input tokens. [MiniMax M3 Token Counter](https://capytoolkit.com/tools/developer/token-counter/minimax-m3-token-count/): Estimate MiniMax M3 tokens in your browser. Approximate count via character formula. See 1M context window usage and live-updated cost at $0.30/M input. [Qwen 3.5 Plus Token Counter](https://capytoolkit.com/tools/developer/token-counter/qwen-35-plus-token-count/): Estimate Qwen 3.5 Plus tokens in your browser. Near-exact count via Qwen3.5 tokenizer reference. See 1M context window usage and cost at $0.30/M input. [Grok 4 Token Counter](https://capytoolkit.com/tools/developer/token-counter/grok-4-token-count/): Estimate Grok 4 tokens in your browser. Approximate count via character formula. See 256K context window usage and cost at $3/M input. ## Guides [Estimating Costs for Batch AI Jobs](https://capytoolkit.com/tools/developer/token-counter/batch-cost-estimation/): Learn how to estimate API costs before running batch AI jobs. Count tokens per request, multiply by volume and price, and budget for model switches. [Choosing Token Chunk Size for RAG Pipelines](https://capytoolkit.com/tools/developer/token-counter/rag-chunk-sizing/): Learn how to choose the right token chunk size for RAG. Measure chunk tokens, balance context window usage, and avoid overflow in retrieval pipelines. [What Happens When Your Prompt Is Too Long](https://capytoolkit.com/tools/developer/token-counter/context-window-overflow/): Understand what context window overflow means, how APIs handle prompts that exceed the limit, and how to prevent truncation before you send. [Writing Token-Efficient Prompts](https://capytoolkit.com/tools/developer/token-counter/prompt-compression/): Reduce prompt token counts without losing quality. Learn which prompt elements waste tokens and how to rewrite instructions for maximum efficiency. [Comparing AI Model Costs by Token Count](https://capytoolkit.com/tools/developer/token-counter/multi-model-cost-comparison/): Learn how to compare AI model costs accurately using token counts. Compare GPT, Claude, Gemini, and 8 more models side by side before you commit. ## Token Counter Reference [What Is an AI Token?](https://capytoolkit.com/tools/developer/token-counter/reference/#what-is-a-token): An AI token is the smallest unit of text that a language model processes. Learn what tokens are, how they differ from words, and why they matter for cost and context. [What Is a Context Window?](https://capytoolkit.com/tools/developer/token-counter/reference/#context-window): A context window is the maximum number of tokens a model can process at once. Learn how it affects prompts, conversations, and RAG pipeline design. [What Is a Tokenizer?](https://capytoolkit.com/tools/developer/token-counter/reference/#tokenizer): A tokenizer converts text into token IDs before an AI model processes it. Learn how tokenizers work, why different models use different tokenizers, and what affects token counts. [Input vs Output Tokens](https://capytoolkit.com/tools/developer/token-counter/reference/#input-vs-output-tokens): Input tokens are what you send to a model. Output tokens are what it generates. Learn why output tokens cost more, and how the ratio affects your API bill. ## Prompt Token Counter: Conversions [Words to Tokens](https://capytoolkit.com/tools/developer/token-counter/conversions/#words-to-tokens): Convert Words to approximate AI tokens using the standard ratio. [Characters to Tokens](https://capytoolkit.com/tools/developer/token-counter/conversions/#characters-to-tokens): Convert Characters to approximate AI tokens using the standard ratio. [Pages to Tokens](https://capytoolkit.com/tools/developer/token-counter/conversions/#pages-to-tokens): Convert Pages to approximate AI tokens using the standard ratio.