AnthropicClaude Opus 4.8VSOpenAIGPT-5.6 Luna

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

This matchup represents a clear tradeoff between peak intelligence and budget efficiency. Claude Opus 4.8 is noticeably superior (holding a 3.9% average lead in benchmarks), but it carries a significant 4.4x price premium. Choose Claude Opus 4.8 if you need top-tier reasoning or code debugging, but for high-volume pipelines, GPT-5.6 Luna is the smarter business decision.

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Model Specs

Claude Opus 4.8

Website

Benchmarks & Scores

Coding (swe-bench-pro)Winner (+6.5%)

69.2%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)Winner (+1.3%)

93.6%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)

$10.00Input: $5.00 | Output: $25.00

Context Window

1.05M tokens

Model Specs

GPT-5.6 Luna

Website

Benchmarks & Scores

Coding (swe-bench-pro)

62.7%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)

92.3%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)4.4x cheaper

$2.25Input: $1.00 | Output: $6.00

Context WindowLarger

1.05M tokens

Read our data collection methodology

Frequently Asked Questions about Claude Opus 4.8 vs GPT-5.6 Luna

GPT-5.6 Luna is cheaper than Claude Opus 4.8. GPT-5.6 Luna has a blended cost of $2.25/1M tokens, which is about 4.4x cheaper than Claude Opus 4.8 at $10.00/1M tokens.

Claude Opus 4.8 is better for coding tasks on this benchmark. It scores 69.2% on swe-bench-pro (excellent at multi-file repositories, autonomous agents, and industrial codebases) compared to GPT-5.6 Luna which scores 62.7%.

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