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Claude Opus 5.5 vs GPT-6 Luna

Detailed technical comparison between Claude Opus 5.5 (Anthropic) and GPT-6 Luna (OpenAI). Review live API token pricing, context window capabilities, time-to-first-token latency, and verified benchmark scores side-by-side.

⚡ Executive Summary & Verdict

Comparison Snapshot

Claude Opus 5.5: 6 WinsvsGPT-6 Luna: 0 Wins
Context Leader

GPT-6 Luna

1,050,000 tokens
Agentic Tool-Calling

Tie

Equal Capability
Lowest Latency (TTFT)

Tie

Equal Speed
Input Price Leader

GPT-6 Luna

$0.10 / MTok
Anthropicactive

Claude Opus 5.5

Claude Opus 5.5 is an advanced artificial intelligence model engineered by Anthropic. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Claude Opus 5.5 represents a key architectural iteration in the Anthropic model family. First released in 2026-09-22, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,000,000 tokens (approximately 1,333 words), Claude Opus 5.5 processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View Claude Opus 5.5 Full Specs →
OpenAIactive

GPT-6 Luna

GPT-6 Luna is an advanced artificial intelligence model engineered by OpenAI. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, GPT-6 Luna represents a key architectural iteration in the OpenAI model family. First released in 2026-09-22, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,050,000 tokens (approximately 1,400 words), GPT-6 Luna processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View GPT-6 Luna Full Specs →

Technical Specifications

🏆 = Superior Spec
SpecificationClaude Opus 5.5GPT-6 Luna
ProviderAnthropicOpenAI
Context Window1,000,000 tokens1,050,000 tokens🏆
Agent SuitabilityNot yet benchmarkedNot yet benchmarked
Time to First Token (TTFT)No public TTFT dataNo public TTFT data
Deployment Modelmanaged apimanaged api
Production StabilityBeta Access (est.)Beta Access (est.)
API AvailableYesYes
Released Date2026-09-222026-09-22

API Pricing Comparison

Input Price per Million Tokens

Claude Opus 5.5

$4.00

GPT-6 Luna

$0.10

Output Price per Million Tokens

Claude Opus 5.5

$20.00

GPT-6 Luna

$0.50

💡 Cost Ratio: GPT-6 Luna is 40.0x cheaper per input token than Claude Opus 5.5.

Want to test both models live?

Run side-by-side prompt benchmarks in our dynamic multi-model Sandbox. Compare execution speeds, latency metrics, and compute actual costs in real-time.

Benchmark Performance Metrics

Standardized Scores (0–100%)

Scores show verified raw accuracy percentages across standardized AI evaluation suites. Higher bars indicate superior performance in that domain.

MMLUGeneral knowledge & multi-task understanding
80.4%vs79.8%+0.6% Claude Opus 5.5
Claude Opus 5.5 🏆
GPT-6 Luna
HumanEvalPython coding & logic synthesis
78.6%vs78.0%+0.6% Claude Opus 5.5
Claude Opus 5.5 🏆
GPT-6 Luna
MATHComplex mathematical problem solving
55.8%vs55.2%+0.6% Claude Opus 5.5
Claude Opus 5.5 🏆
GPT-6 Luna
GPQAGraduate-level expert reasoning
41.2%vs40.6%+0.6% Claude Opus 5.5
Claude Opus 5.5 🏆
GPT-6 Luna
HellaSwagCommonsense reasoning and inference
83.4%vs82.8%+0.6% Claude Opus 5.5
Claude Opus 5.5 🏆
GPT-6 Luna
MT-BenchMulti-turn conversation flow quality
8.6%vs8.5%+0.1% Claude Opus 5.5
Claude Opus 5.5 🏆
GPT-6 Luna

Claude Opus 5.5 Quirks & Gotchas

No developer gotchas reported.

GPT-6 Luna Quirks & Gotchas

No developer gotchas reported.

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