ChatGPT
AI AssistantOpenAI's chat assistant on web, desktop and mobile. Individual plans are Free, Go, Plus and Pro; Business and Enterprise are for organisations. Free runs on GPT-5.6 Luna, and the paid plans add OpenAI's GPT-6 reasoning models.
How It Works
You type a message and the model generates a reply one token at a time, each chosen from the whole conversation so far. When a request needs live data, code execution or an image, the model calls a tool - search, data analysis, image generation - mid-reply and folds the result into its answer.
What each plan runs on, from OpenAI's pricing page (checked 2 October 2026):
- Free: unlimited text chats with GPT-5.6 Luna, with limited uploads, image creation, voice chats and deep research.
- Go: everything in Free with more messages, uploads, image creation and memory. OpenAI notes the plan may include ads.
- Plus: "advanced reasoning models with GPT-6", plus Projects, scheduled tasks and custom GPTs. The GPT-6 family is GPT-6 Astra, GPT-6.1 Sol, GPT-6 Sol and GPT-6 Luna; OpenAI's comparison table does not say which plan gets which.
- Pro: "Pro reasoning powered by GPT-6 Astra", a choice of three usage tiers, and the longest Codex and ChatGPT Work sessions.
The context window grows with the plan too. OpenAI lists 27K tokens for GPT Instant on Free, 54K on Go and Plus and 128K on Pro; for reasoning models it lists 256K on Go and Plus and 400K on Pro.
Plans and pricing
- Free: $0
- Go, Plus and Pro: monthly, charged in local currency at checkout (Pro offers three usage tiers)
- Business: per user per month, from 2 users
- Enterprise: contact sales
- ChatGPT for Teachers: free for verified US K-12 educators through June 2027
- Nonprofits: up to 75% off Business or Enterprise
Key Features
Details from chatgpt.com, checked Oct 2026.