Gemini 3.8 Flash vs Claude Opus 5.5

Pyyan / Compare / Gemini 3.8 Flash vs Claude Opus 5.5

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Language Models · verified 24 Sept 2026

Gemini 3.8 FlashGooglecurrent

Claude Opus 5.5Anthropiccurrent

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Specification	Gemini 3.8 Flash	Claude Opus 5.5
Summary	$0.75 per million in, until the introductory rate ends on 1 January.	Fable 5.1's level of work on most tasks, at 40% less to run than Opus 5.
Context	1M	1M
Input ($/Mtok)	$0.75	$4
Output ($/Mtok)	$3.75	$20
Licence	Proprietary	Proprietary
Max output	64K	128K
Parameters	Not published	Not published
Released	2 Sep 2026	22 Sep 2026
Model ID	gemini-3.8-flash	claude-opus-5-5
Category	Language Models	Language Models
Official	—	Anthropic ↗

Highlighted rows are where these differ.

Introductory pricing runs to 31 December 2026, then input and output both double
A separate Flash Cyber twin clears 70% on real world vulnerability discovery
Flash Cyber is reachable only through the Fairwind Program, by application

Best for high volume work at low cost.

66.4% on Terminal-Bench 4.0 against 52.3% for Opus 5, on Anthropic's own harness
Cache reads cut 60% to $0.20, and output more than 30% faster than Opus 5
Attempts to work around its boundaries 85% less often than Opus 5, Anthropic reports

Best for agentic coding at flagship quality.