Cellm is an innovative Excel add-in that integrates the powerful capabilities of large language models (LLMs) directly into Excel, allowing users to invoke AI models from cell formulas to process data. This advancement significantly enhances Excel's efficiency and flexibility when handling complex text data, especially in scenarios requiring classification, extraction, and summarization of large texts. The main advantage of Cellm is its seamless integration of AI technology with traditional spreadsheet tools, making it accessible to users without programming skills. It supports various mainstream LLMs, including those from Anthropic, Mistral, OpenAI, and Google, as well as models that can run locally. Cellm aims to help users automate repetitive tasks, save time, and enhance productivity. Currently, the tool is offered free of charge, primarily targeting office workers, researchers, and analysts who require efficient text data processing.