TokenCounter is a user-friendly tool designed to estimate the number of tokens and the corresponding costs for various AI models, including those from OpenAI and Anthropic. The tool supports multiple languages and provides real-time token counts as users input their text. TokenCounter is particularly useful for developers and businesses working with language models, allowing them to manage API costs, optimize inputs, and avoid exceeding model limits. Accurate estimation is achieved by using the tiktoken library for OpenAI models and an older method for Anthropic models, with plans to update as new information becomes available.