The GPT Sheets Add-on provides an easy way to access OpenAI GPT-3's powerful capabilities from within Google Sheets. It exposes two simple custom functions: =GPT and =GPT_LIST that can be used for tasks such as generating blogpost ideas, writing paragraphs or procedures, cleaning up lists, classifying reviews, summarizing, writing responses to comments, and experimenting with hyperparameters. The add-on is free to use, with the only cost being OpenAI's API cost.