About GPT-5.6 Terra
GPT-5.6 Terra is the middle tier of the GPT-5.6 family, positioned by OpenAI as the balance point between intelligence and cost — the role mini models played in earlier GPT-5 families. Like its siblings it takes text and images in, writes text out, and exposes the full run of reasoning-effort settings from none to max.
It shares the family's million-token-class context window and tool support — web search, code execution and computer use through the Responses API — so it can anchor agentic workloads without flagship pricing.
Terra's pitch is arithmetic: most requests that would run on Sol produce the same result here at a small fraction of the cost, and OpenAI's positioning steers everyday production traffic this way. Cached input is discounted steeply, though writing a new prefix into the cache costs slightly more than standard input — worth knowing if your prefixes change often. The family's long-prompt multiplier applies above the same threshold as its siblings. If quality falls short on a hard task, escalating just those requests to Sol usually beats moving a whole workload up a tier.
Frequently asked questions
How much does the GPT-5.6 Terra API cost?
GPT-5.6 Terra costs $2 per million input tokens and $12 per million output tokens, with cached input at $0.2 per million (90% off). Note: Prompts over 272K input tokens are billed at 2× input and 1.5× output for the whole request.
How much does a typical chat message cost with GPT-5.6 Terra?
A short chat message (about 500 input and 250 output tokens) costs roughly $0.0040 with GPT-5.6 Terra. At 1,000 such requests a day, that is about $120.00 per month.
Is GPT-5.6 Terra cheap compared to similar models?
GPT-5.6 Terra has the #19 cheapest input rate of the 29 models we track. On a mixed workload (10K input / 2K output), it costs $0.044 per request, versus $0.033 for Gemini 2.5 Pro.
What does GPT-5.6 Terra cost per 1,000 tokens?
Per 1,000 tokens, GPT-5.6 Terra costs $0.0020 for input and $0.0120 for output, or $0.00020 for cached input. Providers quote rates per million tokens ($2/M in, $12/M out here), so divide by a thousand for the per-1K figure older pricing pages used.
How large a prompt can GPT-5.6 Terra take?
GPT-5.6 Terra accepts up to 1025K tokens of input context and can generate up to 125K tokens of output per request. At its input rate, filling the entire 1025K-token window costs about $2.10 per request before any output.
Related
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Last updated 2026-09-03. Prices verified against OpenAI's official pricing page; see the methodology.