Token & Character Counter

Paste text and count tokens, characters, words, sentences, lines and bytes live. Token counting uses the real o200k_base (GPT-4o, GPT-4.1, o-series) and cl100k_base (GPT-3.5, GPT-4) tokenizers, and every token is colour-coded directly in the text. Useful for estimating LLM API costs and context window usage; everything runs locally in your browser, nothing is uploaded.