--- title: "GPT-5.6 family — distinct SKUs · Undominated.ai" canonical: https://undominated.ai/families/gpt-5-6/ description: "Sol, Terra and Luna are distinct named model rows. Pro reasoning mode and reasoning effort are separate controls; a marketplace suffix is not automatically a direct API model ID." --- # GPT-5.6 family — distinct SKUs · Undominated.ai > Sol, Terra and Luna are distinct named model rows. Pro reasoning mode and reasoning effort are separate controls; a marketplace suffix is not automatically a direct API model ID. OpenAI / generation # GPT-5.6 family Sol, Terra and Luna are distinct named model rows. Pro reasoning mode and reasoning effort are separate controls; a marketplace suffix is not automatically a direct API model ID. Family research reviewed 2026-09-22 · Official source notes below Standard models 6 Independently rated 3 / 6 Known token rates 6 / 6 Global balanced frontier 0 [Compare the members ↓](#members)[Read source notes](#source-notes)[All families](https://undominated.ai/families/) [Compare models](https://undominated.ai/compare/) Comparison context Choose up to three standard models in Compare. Requirements and prompt length apply in Compare. This page keeps its stated price basis and workload controls. ## Before you choose ### Model, mode and effort OpenAI documents Sol as the successor to the earlier unsuffixed tier. The direct API treats Pro mode and reasoning effort as separate controls. Confirm the endpoint syntax rather than copying a marketplace slug. [GPT-5.6 Sol ↗](https://developers.openai.com/api/docs/models/gpt-5.6-sol) [OpenAI reasoning guide ↗](https://developers.openai.com/api/docs/guides/reasoning) ## Compare exact catalogue rows USD per 1M tokens. In / out are listed base rates; expand billing conditions before planning a request. LMArena scores measure the general preference board, not success on your engineering task. Unknown stays unknown. ### Pro-labelled catalogue rows | Model | LMArena | Input / output $/M | Context / max output | Capabilities & conditions | | --- | --- | --- | --- | --- | | [GPT-5.6 Luna Pro](https://undominated.ai/models/openai__gpt-5.6-luna-pro/) [Check](https://undominated.ai/check/openai__gpt-5.6-luna-pro/) [Compare](https://undominated.ai/compare/?models=openai%2Fgpt-5.6-luna-pro) [Full evidence ↗](https://undominated.ai/models/openai__gpt-5.6-luna-pro/) openai/gpt-5.6-luna-pro | Unrated | $0.200 / $1.20 Context tiers apply Billing details Cached input $0.020 Separate reasoning Not separately listed Above 272,000 input tokens: $0.400 in / $1.80 out; cached $0.040. Tool, media, cache-write and service-tier charges may add dimensions. Read the full model evidence. | 1,050,000 Output 128,000 | file · image · text Tools yes · reasoning yes Weights unknown Released 2026-07-09 | | [GPT-5.6 Terra Pro](https://undominated.ai/models/openai__gpt-5.6-terra-pro/) [Check](https://undominated.ai/check/openai__gpt-5.6-terra-pro/) [Compare](https://undominated.ai/compare/?models=openai%2Fgpt-5.6-terra-pro) [Full evidence ↗](https://undominated.ai/models/openai__gpt-5.6-terra-pro/) openai/gpt-5.6-terra-pro | Unrated | $2.00 / $12.00 Context tiers apply Billing details Cached input $0.200 Separate reasoning Not separately listed Above 272,000 input tokens: $4.00 in / $18.00 out; cached $0.400. Tool, media, cache-write and service-tier charges may add dimensions. Read the full model evidence. | 1,050,000 Output 128,000 | file · image · text Tools yes · reasoning yes Weights unknown Released 2026-07-09 | | [GPT-5.6 Sol Pro](https://undominated.ai/models/openai__gpt-5.6-sol-pro/) [Check](https://undominated.ai/check/openai__gpt-5.6-sol-pro/) [Compare](https://undominated.ai/compare/?models=openai%2Fgpt-5.6-sol-pro) [Full evidence ↗](https://undominated.ai/models/openai__gpt-5.6-sol-pro/) openai/gpt-5.6-sol-pro | Unrated | $2.00 / $10.00 Context tiers apply Billing details Cached input $0.200 Separate reasoning Not separately listed Above 272,000 input tokens: $4.00 in / $15.00 out; cached $0.400. Tool, media, cache-write and service-tier charges may add dimensions. Read the full model evidence. | 1,050,000 Output 128,000 | file · image · text Tools yes · reasoning yes Weights unknown Released 2026-07-09 | ### Other generation members | Model | LMArena | Input / output $/M | Context / max output | Capabilities & conditions | | --- | --- | --- | --- | --- | | [GPT-5.6 Luna](https://undominated.ai/models/openai__gpt-5.6-luna/) [Check](https://undominated.ai/check/openai__gpt-5.6-luna/) [Compare](https://undominated.ai/compare/?models=openai%2Fgpt-5.6-luna) [Full evidence ↗](https://undominated.ai/models/openai__gpt-5.6-luna/) openai/gpt-5.6-luna | 1429.9 ±4.8 interval half-width Effort: xhigh | $0.200 / $1.20 Context tiers apply Billing details Cached input $0.020 Separate reasoning Not separately listed Above 272,000 input tokens: $0.400 in / $1.80 out; cached $0.040. Tool, media, cache-write and service-tier charges may add dimensions. Read the full model evidence. | 1,050,000 Output 128,000 | file · image · text Tools yes · reasoning yes Closed weights Released 2026-07-09 | | [GPT-5.6 Terra](https://undominated.ai/models/openai__gpt-5.6-terra/) [Check](https://undominated.ai/check/openai__gpt-5.6-terra/) [Compare](https://undominated.ai/compare/?models=openai%2Fgpt-5.6-terra) [Full evidence ↗](https://undominated.ai/models/openai__gpt-5.6-terra/) openai/gpt-5.6-terra | 1446.2 ±4.8 interval half-width Effort: xhigh | $2.00 / $12.00 Context tiers apply Billing details Cached input $0.200 Separate reasoning Not separately listed Above 272,000 input tokens: $4.00 in / $18.00 out; cached $0.400. Tool, media, cache-write and service-tier charges may add dimensions. Read the full model evidence. | 1,050,000 Output 128,000 | file · image · text Tools yes · reasoning yes Closed weights Released 2026-07-09 | | [GPT-5.6 Sol](https://undominated.ai/models/openai__gpt-5.6-sol/) [Check](https://undominated.ai/check/openai__gpt-5.6-sol/) [Compare](https://undominated.ai/compare/?models=openai%2Fgpt-5.6-sol) [Full evidence ↗](https://undominated.ai/models/openai__gpt-5.6-sol/) openai/gpt-5.6-sol | 1455.1 ±4.9 interval half-width Effort: xhigh | $2.00 / $10.00 Context tiers apply Billing details Cached input $0.200 Separate reasoning Not separately listed Above 272,000 input tokens: $4.00 in / $15.00 out; cached $0.400. Tool, media, cache-write and service-tier charges may add dimensions. Read the full model evidence. | 1,050,000 Output 128,000 | file · image · text Tools yes · reasoning yes Closed weights Released 2026-07-09 | ## Free and batch variants These rows have different access or processing conditions. They are excluded from the standard-row counts above. A variant without a standard base remains a separately named variant. - [GPT-5.6 Luna Pro (batch)](https://undominated.ai/models/openai__gpt-5.6-luna-pro__batch/) batch · $0.100 in / $0.600 out per 1M - [GPT-5.6 Luna (batch)](https://undominated.ai/models/openai__gpt-5.6-luna__batch/) batch · $0.100 in / $0.600 out per 1M - [GPT-5.6 Terra Pro (batch)](https://undominated.ai/models/openai__gpt-5.6-terra-pro__batch/) batch · $1.00 in / $6.00 out per 1M - [GPT-5.6 Terra (batch)](https://undominated.ai/models/openai__gpt-5.6-terra__batch/) batch · $1.00 in / $6.00 out per 1M - [GPT-5.6 Sol Pro (batch)](https://undominated.ai/models/openai__gpt-5.6-sol-pro__batch/) batch · $1.00 in / $5.00 out per 1M - [GPT-5.6 Sol (batch)](https://undominated.ai/models/openai__gpt-5.6-sol__batch/) batch · $1.00 in / $5.00 out per 1M ## Sources and scope - [GPT-5.6 Sol ↗](https://developers.openai.com/api/docs/models/gpt-5.6-sol) Exact named models on the vendor platform; not a promise about every reseller Checked 2026-09-22 · official document opened and inspected - [OpenAI reasoning guide ↗](https://developers.openai.com/api/docs/guides/reasoning) Exact named models on the vendor platform; not a promise about every reseller Checked 2026-09-22 · web opened; full official Markdown fetched with HTTP 200 and inspected Source review does not refresh a price or transplant a benchmark score. [Read the method](https://undominated.ai/methodology/) and [correction policy](https://undominated.ai/corrections/). ## Questions this page answers Are the GPT-5.6 family models interchangeable? No. These are exact catalogue rows with separate capability, pricing and rating evidence. Compare the checkpoint, serving endpoint, reasoning settings and required input types. A family name does not establish equivalent behaviour. How many OpenAI rows are compared here? 6 standard rows, of which 3 have an accepted LMArena general score and 6 have known input and output token rates. 6 related free or batch variants are listed separately. What do the prices and frontier counts mean? Prices below are listed US dollars per million input or output tokens, before request-specific context tiers and other billing dimensions. The frontier count comes from the global balanced view. Neither a family price range nor a benchmark difference proves your task will be cheaper or more successful. How current are the official notes? The linked family research was reviewed 2026-09-22. That date is separate from each accepted catalogue observation and each vendor’s effective date. An official note applies to its named platform, not automatically to every reseller. ## Continue your investigation - [Compare exact models](/compare/) - [Inspect model evidence](/models/) - [Check lifecycle notices](/deprecations/) - [Estimate local capacity](/self-host/)