OpenAI Models Reach 1 Billion Active Users and 2 Million Enterprises
OpenAI announced that its AI models have reached over 1 billion active users and 2 million enterprises globally. Additionally, the company has lowered the API usage costs for its GPT-5.6 Terra and GPT-5.6 Luna models to reduce expenses for developers and businesses. This milestone highlights the massive scale of AI adoption in both consumer and enterprise sectors, shifting ChatGPT's role from simple Q&A to executing complex, multi-step workflows. Lowering API costs for the GPT-5.6 family makes advanced AI capabilities more accessible, accelerating integration into everyday business applications. According to OpenAI, users send about 50% more messages daily six weeks after registering for ChatGPT, and the variety of tasks completed has doubled. The GPT-5.6 family includes Sol (flagship), Terra (balanced everyday model), and Luna (fastest and most affordable), with Terra priced at $1 per million input tokens and $6 per million output tokens.
## BACKGROUND
OpenAI launched the GPT-5.6 series in July 2026, introducing three tiers tailored for different performance and cost requirements: Sol, Terra, and Luna. Prior to this, businesses faced high computational costs when deploying large language models for complex agentic workflows, prompting OpenAI to continuously optimize pricing.