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OpenAI

GPT-5.6 Luna

  • Released
  • Closed weights
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Intelligence Index

Max setting

37.3
Measured · Artificial Analysis v4.3.2
API price from
$0.20 in / $1.20 out / 1M tokOpenAI · direct API
Context window
1.05M tok

Performance profile

ReasoningArchived source
91.1%
GPQA Diamond
CodingArchived source
53.6%
SciCode
Cost efficiencyArchived source
209.3pts / $
Intelligence ÷ eval cost

Capabilities

Context window

Modalities

Reasoning modes

Integration

Reasoning trade-offs

Source (opens in a new tab)
Intelligence Index v4.3.2
GPT-5.6 Luna
Cost per task (USD) · log scale
GPT-5.6 LunaMax
Intelligence Index
37.3
Cost / task
$0.1783
Evaluation time
4.7m

Pricing & access

API route
OpenAIAPI
Tier & context

USD per 1M tokens

Input
$0.20
Output
$1.20
Cached input
$0.02
Responses API tool compatibility (opens in a new tab)
  • Web search
  • File search
  • Image generation
  • Code execution
  • Shell
  • File edits
  • Skills
  • Computer use
  • MCP
  • Tool search

Available plans · USD

All plans for ChatGPT (opens in a new tab)

Personal

Free
$0/moNot included
Go
$8/moAccess not verified
Plus
$20/mo
Pro 100
$100/mo
Pro 200
$200/mo
Pro 500
$500/mo
Organizations4 plans
Business Standard
$25/seat/mo
Business Premium
$125/seat/mo
Enterprise
Custom
Edu
Custom

Benchmarks

Full leaderboardSource (opens in a new tab)

Humanity’s Last Exam

Frontier reasoning

GPT-5.6 Luna · MaxArchived

  1. 1Claude Opus 5.5Max61.4%
  2. 2Claude Fable 5.1Max59.1%
  3. 3Gemini 4 ArgonHigh57.1%
  4. 4Claude Sonnet 5.5Max55.0%
  5. 5GPT-6 AstraMax54.7%
  6. 6Muse Wonder FullMax53.6%
  7. 7GPT-6.1 SolMax52.9%
  8. 8Muse WonderMax50.1%
  9. 9MiMo-V2.6-ProReasoning49.4%
  10. 10Muse Spark 1.3Max48.7%

Peers use their best measured result on this benchmark.