GPT-5.5 vs GPT-5.6 Terra

OpenAI's GPT-5.5 against OpenAI's GPT-5.6 Terra — price, context and what each is best at. Both are available through one OpenAI-compatible API.

AnyModel — you pay	GPT-5.5	GPT-5.6 Terra
Vendor	OpenAI	OpenAI
Input / 1M	$0.05	$0.05
Output / 1M	$0.05	$0.05
Context	1M	1M
Best for	Complex coding	Daily coding

GPT-5.5

OpenAI's flagship for coding, agents and research-grade reasoning.

GPT-5.5 is OpenAI's top general-purpose model and the engine behind modern Codex: state-of-the-art coding, computer use and multi-step reasoning with a ~1M-token window. The default pick when you want one model that handles everything.

More about GPT-5.5 →

GPT-5.6 Terra

Balanced agentic coding model for everyday work.

GPT-5.6 Terra is the balanced tier of the GPT-5.6 line: strong agentic coding at lower latency and cost than Sol. The default pick for day-to-day engineering and production coding agents.

More about GPT-5.6 Terra →

Quick take: GPT-5.5 and GPT-5.6 Terra cost the same on output tokens ($0.05 per 1M). Compare their strengths and context for your task; you can switch the model id at any time.

FAQ

Which is cheaper, GPT-5.5 or GPT-5.6 Terra?

GPT-5.5 and GPT-5.6 Terra cost the same on output tokens ($0.05 per 1M).

Which has a larger context window, GPT-5.5 or GPT-5.6 Terra?

GPT-5.5: 1M; GPT-5.6 Terra: 1M.