Which is cheaper, Claude Opus 5.5 or GPT-5.6 Luna?

Claude Opus 5.5 lists at $4 input / $20 output per 1M tokens; GPT-5.6 Luna lists at $0.20 input / $1.20 output per 1M tokens. GPT-5.6 Luna has the lower list price.

Updated Sep 26, 2026

Claude Opus 5.5 vs GPT-5.6 Luna

Claude Opus 5.5 does not have enough reviewed code to rank yet.

Claude Opus 5.5 and GPT-5.6 Luna compared on relative bug rate, by coding agent, bug type, and language, and on price and usage.
Bug rate
	Claude Opus 5.5	GPT-5.6 Luna
Relative bug rate	Launch week	1.28
Details
Provider	Anthropic	OpenAI
Released	Sep 22, 2026	Jul 9, 2026
List price	$4 input / $20 output per 1M tokens	$0.20 input / $1.20 output per 1M tokens

1.00 = average · lower is better

More comparisons

All comparisons →

Claude Opus 5.5 vs GPT-5.5
Claude Opus 5.5 vs Claude Fable 5
Claude Opus 5.5 vs GPT-5.6 Sol
GPT-5.6 Luna vs Claude Fable 5.1
GPT-5.6 Luna vs Claude Opus 5
GPT-5.6 Luna vs GPT-6 Astra

Questions and answers

Which has fewer bugs, Claude Opus 5.5 or GPT-5.6 Luna?: Claude Opus 5.5 does not have enough reviewed code to rank yet.
Which is cheaper, Claude Opus 5.5 or GPT-5.6 Luna?: Claude Opus 5.5 lists at $4 input / $20 output per 1M tokens; GPT-5.6 Luna lists at $0.20 input / $1.20 output per 1M tokens. GPT-5.6 Luna has the lower list price.