Claude Opus 5.5 vs Gemini 4 Argon: price, scores, context

Side-by-side comparison

Criterion	Claude Opus 5.5	Gemini 4 Argon
Developer	Anthropic	Google DeepMind
Released	September 22, 2026	October 13, 2026
Capability index	95.9 / 100	95.3 / 100
Input price	$4	$2
Output price	$20	$10
Cost of a typical task	$0.12	$0.06
Context window	1,000,000 tokens	1,048,576 tokens
Maximum output	128,000 tokens	32,768 tokens
Reasoning mode	Yes	Yes
Tool calling	Yes	Yes
Accepted inputs	text, image, PDF	text, image, video, audio, PDF
Open weights	No	No
Knowledge cutoff	June 2026	March 2026

What are we comparing?

Claude Opus 5.5 and Gemini 4 Argon are two frontier models, the ones you pick when quality comes first, one from Anthropic, the other from Google DeepMind. Claude Opus 5.5 was released on September 22, 2026, Gemini 4 Argon on October 13, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

Performance

On our capability index, Claude Opus 5.5 scores 95.9 out of 100 and Gemini 4 Argon 95.3. The gap is too small to separate them.

On the 5 benchmarks reported for both, Claude Opus 5.5 wins 2 times and Gemini 4 Argon 2:

GPQA Diamond (PhD-level science questions): Claude Opus 5.5 90.6%, Gemini 4 Argon 96.4%
OTIS Mock AIME (competition mathematics problems): Claude Opus 5.5 100%, Gemini 4 Argon 100%
FrontierMath (very hard research-level mathematics): Claude Opus 5.5 91.2%, Gemini 4 Argon 86%
FrontierCode (advanced programming tasks): Claude Opus 5.5 54.6%, Gemini 4 Argon 47.6%
APEX-Agents (professional tasks carried out by an agent): Claude Opus 5.5 73.5%, Gemini 4 Argon 82.4%

Which one costs less?

Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens; Gemini 4 Argon costs $2 and $10.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.12 with Claude Opus 5.5 versus $0.06 with Gemini 4 Argon. Gemini 4 Argon is 2 times cheaper, a gap that adds up quickly over 1,000 tasks: $60 difference.

Run the numbers with your own volumes in the agent cost calculator.

Under the hood

Gemini 4 Argon reads more in one go: 1,048,576 tokens of context (roughly 1,573 pages), versus 1,000,000 for Claude Opus 5.5.

Reasoning mode: Claude Opus 5.5 yes, Gemini 4 Argon yes. Tool calling: Claude Opus 5.5 yes, Gemini 4 Argon yes. Image input: Claude Opus 5.5 yes, Gemini 4 Argon yes.

Neither publishes its weights: both are used through an API.

Knowledge cutoff: June 2026 for Claude Opus 5.5, March 2026 for Gemini 4 Argon.

In short

Our reading of the data:

Choose Gemini 4 Argon for a lower cost.

This verdict relies on public figures; it does not replace a trial on your own tasks.

Frequently asked questions

Claude Opus 5.5 or Gemini 4 Argon: which is better?

On our index (Epoch AI data), Claude Opus 5.5 scores 95.9 and Gemini 4 Argon 95.3 out of 100. The best choice also depends on price and on your use case.

Which one is cheaper?

Gemini 4 Argon. To read 20,000 tokens and write 2,000, expect $0.12 with Claude Opus 5.5 and $0.06 with Gemini 4 Argon (prices as of October 22, 2026).

Which one has the larger context window?

Gemini 4 Argon, with 1,048,576 tokens versus 1,000,000.

Can I run Claude Opus 5.5 or Gemini 4 Argon on my own servers?

No: both are closed models, available through an API.

Claude Opus 5.5 vs Gemini 4 Argon