Claude Opus 5.5 vs Gemini 4 Argon vs GPT-6.1 Sol
Too close to call on our weighted score (Gemini 4 Argon 74, GPT-6.1 Sol 72, Claude Opus 5.5 69). The right pick depends on what you value most.
AnthropicClaude Opus 5.5
69/100- ECI168.4
- Price$4.00 / $20.00
- Context1M
GoogleGemini 4 Argon
74/100- ECI166.1
- Price$2.00 / $10.00
- Context1.05M
OpenAIGPT-6.1 Sol
72/100- ECI167.8
- Price$2.00 / $10.00
- Context1.05M
Too close to call
It is close. Our weighted score puts them within 2 points (Gemini 4 Argon 74/100, GPT-6.1 Sol 72/100, Claude Opus 5.5 69/100), so choose by what matters most for your work: Claude Opus 5.5 for raw capability and Gemini 4 Argon on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Opus 5.5Capabilities Index (ECI): Claude Opus 5.5 168.4 · GPT-6.1 Sol 167.8 · Gemini 4 Argon 166.1
- Lowest priceGemini 4 Argon and GPT-6.1 SolGemini 4 Argon $4.00 · GPT-6.1 Sol $4.00 · Claude Opus 5.5 $8.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6.1 Sol and Gemini 4 ArgonGPT-6.1 Sol 1,050,000 · Gemini 4 Argon 1,048,576 · Claude Opus 5.5 1,000,000 tokens
- Widest inputsGemini 4 ArgonClaude Opus 5.5: Text, Images, PDFs · Gemini 4 Argon: Text, Images, PDFs, Audio, Video · GPT-6.1 Sol: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Opus 5.5 | Gemini 4 Argon | GPT-6.1 Sol |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 99 | 96 | 99 |
| Price | 25% | 7 | 20 | 20 |
| Inputs & features | 15% | 80 | 100 | 80 |
| Context window | 10% | 60 | 61 | 61 |
| Overall | 100% | 69/100 | 74/100 | 72/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Opus 5.5Anthropic | Gemini 4 ArgonGoogle | GPT-6.1 SolOpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 168.4 (best) | 166.1 | 167.8 |
| ECI rank | #2 of 165 (best) | #7 of 165 | #4 of 165 |
| GPQA DiamondGraduate-level science questions | 90.6% | 96.4% (best) | 95.4% |
| FrontierMath Tiers 1–3Research-level mathematics | 91.2% | 86.0% | 93.7% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% | 100% | 100% |
| SimpleQA VerifiedShort factual questions | 72.2% | 76.0% (best) | 73.9% |
| Price per million tokens | |||
| Input | $4.00 | $2.00 (best) | $2.00 (best) |
| Output | $20.00 | $10.00 (best) | $10.00 (best) |
| Cached input | $0.20 | $0.10 (best) | $0.10 (best) |
| Blended (3:1) | $8.00 | $4.00 (best) | $4.00 (best) |
| Long-context rate | Same rate | Same rate | Over 272K: $4.00 / $15.00 |
| Price source | Official Anthropic API | Official Google API | Official OpenAI API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens | 1,050,000 tokens (best) |
| Max output | 128,000 tokens (best) | 65,536 tokens | 128,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · medium · high | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-opus-5-5 | gemini-4-argon | gpt-6.1-sol |
| API providers | 36 (best) | 24 | 33 |
| Released | Sep 22, 2026 | Oct 13, 2026 | Sep 29, 2026 |
| Knowledge cutoff | Jun 2026 | Mar 2026 | Apr 30, 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Claude Opus 5.5$80.00
- Gemini 4 Argon$40.00
- GPT-6.1 Sol$40.00
Which should you choose?
Which is better: Claude Opus 5.5, Gemini 4 Argon or GPT-6.1 Sol?
It is close. Our weighted score puts them within 2 points (Gemini 4 Argon 74/100, GPT-6.1 Sol 72/100, Claude Opus 5.5 69/100), so choose by what matters most for your work: Claude Opus 5.5 for raw capability and Gemini 4 Argon on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Opus 5.5, Gemini 4 Argon or GPT-6.1 Sol?
Gemini 4 Argon is cheaper at $2.00 input / $10.00 output per million tokens (official Google API price). GPT-6.1 Sol costs $2.00 input / $10.00 output per million tokens (official OpenAI API price); Claude Opus 5.5 costs $4.00 input / $20.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $4.00 per million tokens for Gemini 4 Argon versus $4.00 for GPT-6.1 Sol (1× as much) and $8.00 for Claude Opus 5.5 (2× as much).
Which scores higher on benchmarks?
Claude Opus 5.5 scores higher on the Capabilities Index (ECI): Claude Opus 5.5 168.4 (#2 of 165), GPT-6.1 Sol 167.8 (#4 of 165) and Gemini 4 Argon 166.1 (#7 of 165). The confidence ranges of the top two overlap (165.4–173.0 vs 164.3–172.5), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 4 Argon 96.4%, GPT-6.1 Sol 95.4%, Claude Opus 5.5 90.6%; FrontierMath Tiers 1–3 — GPT-6.1 Sol 93.7%, Claude Opus 5.5 91.2%, Gemini 4 Argon 86.0%; OTIS Mock AIME 2024–2025 — Claude Opus 5.5 100%, Gemini 4 Argon 100%, GPT-6.1 Sol 100%; SimpleQA Verified — Gemini 4 Argon 76.0%, GPT-6.1 Sol 73.9%, Claude Opus 5.5 72.2%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Opus 5.5, Gemini 4 Argon and GPT-6.1 Sol yet, so there is no like-for-like coding score. On overall capability, Claude Opus 5.5 leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-6.1 Sol and Gemini 4 Argon have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for Claude Opus 5.5. Maximum output per response: Claude Opus 5.5 up to 128,000, Gemini 4 Argon up to 65,536, GPT-6.1 Sol up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Opus 5.5 accepts text, images and PDFs; Gemini 4 Argon accepts text, images, PDFs, audio and video; GPT-6.1 Sol accepts text, images and PDFs. Gemini 4 Argon handles the widest range of inputs.
Are any of these open source?
No. Claude Opus 5.5, Gemini 4 Argon and GPT-6.1 Sol are proprietary and only available through APIs and apps.
Which is newer?
Gemini 4 Argon is the newest, released Oct 13, 2026. GPT-6.1 Sol came out Sep 29, 2026; Claude Opus 5.5 came out Sep 22, 2026. Knowledge cutoff: Claude Opus 5.5 Jun 2026, Gemini 4 Argon Mar 2026, GPT-6.1 Sol Apr 30, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
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