GPT-5.5 vs GPT-5.6 Sol

OpenAI's GPT-5.5 against OpenAI's GPT-5.6 Sol — 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 Sol
Vendor	OpenAI	OpenAI
Input / 1M	$0.15	$0.2
Output / 1M	$0.15	$0.2
Context	400K	400K
Best for	Complex coding	Codex CLI

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 400K-token window on this route. The default pick when you want one model that handles everything.

More about GPT-5.5 →

GPT-5.6 Sol

Latest frontier agentic coding model — the new Codex default.

GPT-5.6 Sol is OpenAI's newest frontier model for agentic coding: the default engine of modern Codex, tuned for long autonomous sessions, repo-scale edits and reliable tool calling. Pick it when you want the strongest coder in the GPT line.

More about GPT-5.6 Sol →

Quick take: GPT-5.5 is cheaper on output tokens ($0.15 vs $0.2 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 Sol?

GPT-5.5 is cheaper on output tokens ($0.15 vs $0.2 per 1M).

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

GPT-5.5: 400K; GPT-5.6 Sol: 400K.