Claude Opus 5.5 vs Gemini 4 Argon: 2026 comparison

Claude Opus 5.5 and Gemini 4 Argon in brief

Claude Opus 5.5 and Gemini 4 Argon both support long inputs, reasoning and tool calling. Their differences concern media support, maximum output length and token prices. Gemini adds audio and video to text, image and file inputs while charging half as much per token. Claude has a higher Epoch capability index and leads on some supplied benchmarks. The practical choice depends on connecting those differences to your content and tasks, rather than assuming that a single evaluation settles the comparison.

Claude Opus 5.5 : Claude Opus 5.5 (Anthropic): $4 / $20 per million tokens, 1M context, benchmarks, verdict and alternatives. Checked October 25, 2026.

Gemini 4 Argon : Gemini 4 Argon (Google): $2 / $10 per million tokens, 1M context, benchmarks, verdict and alternatives. Checked October 25, 2026.

Both meet the same need, which makes the comparison useful. We compare them on 11 verifiable criteria, using the same data as their profiles, collected from official sites, OpenRouter and Epoch AI.

Comparison table

Criterion by criterion

For each criterion: why it matters, each one's value and who has the edge. A criterion without data on both sides is not decided.

Capabilities (Epoch AI index)

Epoch AI's capabilities index rolls many benchmarks into one number: the higher, the better the model does on hard tasks. Claude Opus 5.5 : 168.8. Gemini 4 Argon : 166.5. Edge: Claude Opus 5.5.

Shared benchmarks

On the benchmarks both models took, we count each one's wins. Claude Opus 5.5 : 2 of 6. Gemini 4 Argon : 2 of 6. A tie on this point.

Input price

The price of tokens sent to the model weighs heavily as soon as you send long documents or chat history. Claude Opus 5.5 : $4 / M tokens. Gemini 4 Argon : $2 / M tokens. Edge: Gemini 4 Argon.

Output price

Generated tokens usually cost several times more; they dominate the bill for writing and code. Claude Opus 5.5 : $20 / M tokens. Gemini 4 Argon : $10 / M tokens. Edge: Gemini 4 Argon.

Cost of a typical task

For a request of 2,000 input and 500 output tokens, repeated 30,000 times a month (1,000 a day). Claude Opus 5.5 : $540 per month. Gemini 4 Argon : $270 per month. Edge: Gemini 4 Argon.

Context window

The context window sets how much text the model reads at once: useful for long documents and agents. Claude Opus 5.5 : 1M tokens. Gemini 4 Argon : 1M tokens. Edge: Gemini 4 Argon.

Max output

The maximum answer length matters to generate long code files or reports. Claude Opus 5.5 : 128K tokens. Gemini 4 Argon : 943.7K tokens. Edge: Gemini 4 Argon.

Accepted inputs

Text, images, files, audio: the more formats accepted, the more cases covered without extra tools. Claude Opus 5.5 : 3. Gemini 4 Argon : 5. Edge: Gemini 4 Argon.

Tool calling

Essential for an agent: the model can call functions, APIs or MCP servers. Claude Opus 5.5 : yes. Gemini 4 Argon : yes. A tie on this point.

Open weights

Downloadable weights let you run the model yourself, without sending data to a provider. Claude Opus 5.5 : no. Gemini 4 Argon : no. A tie on this point.

Release date

A newer model often has fresher data and better training techniques. Claude Opus 5.5 : September 22, 2026. Gemini 4 Argon : October 13, 2026. Edge: Gemini 4 Argon.

In charts

Our analysis

Anthropic released Claude Opus 5.5 on September 22, 2026, with text, image and file inputs. Google released Gemini 4 Argon on October 13, adding audio and video to those categories. Both support reasoning and tool calling. Their declared functions therefore overlap for document-focused applications, while Gemini explicitly accommodates a wider range of source media. If your work includes recordings or video, that distinction is directly relevant. The profiles do not explain detailed media handling, output formats or response styles. They also do not establish a particular professional specialization for either model, so those judgments require evidence beyond the listed features.

Claude scores 91.2% on FrontierMath and 93.3% on ARC2, compared with Gemini’s 86% and 91.3%. Gemini leads on GPQA, at 96.4% against 90.6%, and SimpleQA, at 76% against 72.2%. Both reach 100% on AIME and 98.5% on ARC1. Claude also has the higher Epoch capability index, at 168.83 versus 166.45. The performance comparison consequently depends on which measure you prioritize. Claude’s prices are $4 per million input tokens and $20 per million output tokens. Gemini charges $2 and $10, respectively, making its listed rates half as high for an equal number of tokens in either category.

Neither Claude nor Gemini has open weights, and neither profile specifies a license. Both publishers are listed as US companies, which does not establish where your information would be stored or processed. Retention rules, deletion procedures and any use of submitted material for training are also absent from the supplied data. You therefore cannot derive a privacy advantage for either model from these profiles. If your application involves internal documents or sensitive recordings, the effective conditions require separate examination. Gemini’s broader input support describes what you can submit, but does not answer how that information is handled after submission.

Claude has a context window of 1,000,000 tokens and a maximum output of 128,000 tokens. Gemini provides a 1,048,576-token context and allows up to 943,718 output tokens. That generation limit may matter greatly if you need very long responses, although it does not guarantee coherence throughout them. If your expected outputs are short, the additional allowance may contribute little to the decision. Neither profile reports latency, throughput or availability. For everyday integration, evaluate representative content and the amount of output actually produced, since token volume affects spending as well as whether the declared length limits are relevant to you.

Depending on your situation

The right choice depends on use. For a few common situations, here are the criteria that matter and who wins (Claude Opus 5.5 value / Gemini 4 Argon value).

High request volume

Here, Gemini 4 Argon has the edge: it wins 3 of the 3 criteria that matter in this situation, namely cost of a typical task ($540 per month / $270 per month), input price ($4 / M tokens / $2 / M tokens), and output price ($20 / M tokens / $10 / M tokens).

Hard tasks (reasoning, code)

Neither stands out on the criteria for this situation (capabilities (epoch ai index) (168.8 / 166.5), shared benchmarks (2 of 6 / 2 of 6), and max output (128K tokens / 943.7K tokens)): decide with a trial.

Agents and long documents

Here, Gemini 4 Argon has the edge: it wins 2 of the 3 criteria that matter in this situation, namely tool calling (yes / yes), context window (1M tokens / 1M tokens), and accepted inputs (3 / 5).

Maximum privacy

Neither stands out on the criteria for this situation (open weights (no / no)): decide with a trial.

Which one to choose?

Choose Claude Opus 5.5 if…

• you value capabilities (epoch ai index) (168.8)

Claude Opus 5.5 is a reasonable candidate if FrontierMath or ARC2 is particularly relevant to your tasks and you give weight to its higher Epoch index. Text, image and file inputs may cover your requirements fully. Its higher token prices should then be assessed against representative results, rather than justified by the aggregate capability index alone without practical testing.

Choose Gemini 4 Argon if…

• you value input price ($2 / M tokens)
• you value output price ($10 / M tokens)
• you value cost of a typical task ($270 per month)
• you value context window (1M tokens)
• you value max output (943.7K tokens)

Gemini 4 Argon makes sense if you need audio or video inputs, unusually long outputs or lower token rates. Its stronger GPQA and SimpleQA results provide additional reasons to consider it. The value of its much larger output allowance depends on your actual generation needs, while its price advantage applies to equal token volumes in both listed billing categories.

Strengths and limits of each

Claude Opus 5.5

• + Among the top 20% of models according to Epoch AI (ECI 168.8).
• + Very large context (1M tokens): long documents or a whole codebase fit in one request.
• + Agent-ready: tool calling and structured JSON output.
• − Expensive: costlier than 93 % of paid models.

Gemini 4 Argon

• + Among the top 20% of models according to Epoch AI (ECI 166.5).
• + Very large context (1M tokens): long documents or a whole codebase fit in one request.
• + Agent-ready: tool calling and structured JSON output.
• − Expensive: costlier than 84 % of paid models.

The best test is still yours: take three real tasks from your day and give them to both for a week. The price calculator works out the gap on your own volume.

What about the others?

If neither suits you, look at GPT-6 Astra, GPT-6.1 Sol, Claude Fable 5.1, Claude Sonnet 5.5, Claude Opus 5, and GPT-6 Sol.

Related comparisons:

• Claude Opus 5.5 vs GPT-6.1 Sol
• Gemini 4 Argon vs GPT-6.1 Sol
• Claude Opus 5.5 vs GPT-6 Astra
• Claude Opus 5.5 vs Muse Wonder
• GPT-6 Astra vs Gemini 4 Argon

Conclusion

Gemini offers a clear token pricing advantage, broader input support and a substantially higher maximum output length. Claude leads on FrontierMath and ARC2 and has the higher Epoch capability index. Begin with the media you must process, expected token volumes and representative tasks. None of these indicators settles every use case, and the supplied profiles do not provide enough information to compare privacy commitments or day-to-day service performance.