AnthropicClaude Opus 5VSOpenAIGPT-5.6 Luna
Our Take
We recommend Claude Opus 5 if your workflow requires peak coding capability, or the 4.4x cheaper GPT-5.6 Luna to optimize your API budget. While both models deliver similar reasoning performance, Claude Opus 5 holds a clear lead in coding. Choose Claude Opus 5 for complex development tasks, or GPT-5.6 Luna for cost optimization.
▶WHY?
Benchmark Calculations & Evidence:
Coding Benchmarks: Both models were evaluated on the SWE-bench Pro benchmark. Claude Opus 5 scored 79.2%, while GPT-5.6 Luna scored 62.7%.
Reasoning Benchmarks: Both models were evaluated on the GPQA Diamond benchmark. Claude Opus 5 scored 93.7%, while GPT-5.6 Luna scored 92.3%.
Cost Efficiency: GPT-5.6 Luna pricing ($1/M input, $6/M output) is 4.4x cheaper than Claude Opus 5 ($5/M input, $25/M output).
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Benchmarks & Scores
Coding (swe-bench-pro)Winner (+16.5%)
79.2%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)Winner (+1.4%)
93.7%graduate-level science QA
Cost & Context
Cost (per 1M tokens)
$10.00Input: $5.00 | Output: $25.00Context Window
1.05M tokensBenchmarks & Scores
Coding (swe-bench-pro)
62.7%complex codebases, multi-file repositories, and architectural planning
Reasoning (gpqa-diamond)
92.3%graduate-level science QA
Cost & Context
Cost (per 1M tokens)4.4x cheaper
$2.25Input: $1.00 | Output: $6.00Context WindowLarger
1.05M tokensFrequently Asked Questions about Claude Opus 5 vs GPT-5.6 Luna
GPT-5.6 Luna is cheaper than Claude Opus 5. GPT-5.6 Luna has a blended cost of $2.25/1M tokens, which is about 4.4x cheaper than Claude Opus 5 at $10.00/1M tokens.
Claude Opus 5 is better for coding tasks on this benchmark. It scores 79.2% on swe-bench-pro (complex codebases, multi-file repositories, and architectural planning) compared to GPT-5.6 Luna which scores 62.7%.
Related Matchups
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