GPT-6.1 Terra vs Claude Sonnet 5.5 vs Gemini 4 Argon
Too close to call on our weighted score (GPT-6.1 Terra 76, Gemini 4 Argon 74, Claude Sonnet 5.5 72). The right pick depends on what you value most.
OpenAIGPT-6.1 Terra
76/100- ECI168.1
- Price$1.00 / $5.00
- Context1.05M
AnthropicClaude Sonnet 5.5
72/100- ECI166.7
- Price$2.00 / $10.00
- Context1M
GoogleGemini 4 Argon
74/100- ECI166.1
- Price$2.00 / $10.00
- Context1.05M
Too close to call
It is close. Our weighted score puts them within 2 points (GPT-6.1 Terra 76/100, Gemini 4 Argon 74/100, Claude Sonnet 5.5 72/100), so choose by what matters most for your work: GPT-6.1 Terra for raw capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-6.1 TerraCapabilities Index (ECI): GPT-6.1 Terra 168.1 · Claude Sonnet 5.5 166.7 · Gemini 4 Argon 166.1
- Lowest priceGPT-6.1 TerraGPT-6.1 Terra $2.00 · Claude Sonnet 5.5 $4.00 · Gemini 4 Argon $4.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6.1 Terra and Gemini 4 ArgonGPT-6.1 Terra 1,050,000 · Gemini 4 Argon 1,048,576 · Claude Sonnet 5.5 1,000,000 tokens
- Widest inputsGemini 4 ArgonGPT-6.1 Terra: Text, Images, PDFs · Claude Sonnet 5.5: Text, Images, PDFs · Gemini 4 Argon: Text, Images, PDFs, Audio, Video
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | GPT-6.1 Terra | Claude Sonnet 5.5 | Gemini 4 Argon |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 99 | 97 | 96 |
| Price | 25% | 34 | 20 | 20 |
| Inputs & features | 15% | 80 | 80 | 100 |
| Context window | 10% | 61 | 60 | 61 |
| Overall | 100% | 76/100 | 72/100 | 74/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-6.1 TerraOpenAI | Claude Sonnet 5.5Anthropic | Gemini 4 ArgonGoogle |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 168.1 (best) | 166.7 | 166.1 |
| ECI rank | #3 of 165 (best) | #5 of 165 | #7 of 165 |
| GPQA DiamondGraduate-level science questions | 94.3% | 95.6% | 96.4% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 90.9% (best) | 88.8% | 86.0% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% | 100% | 100% |
| SimpleQA VerifiedShort factual questions | 57.3% | 46.5% | 76.0% (best) |
| Price per million tokens | |||
| Input | $1.00 (best) | $2.00 | $2.00 |
| Output | $5.00 (best) | $10.00 | $10.00 |
| Cached input | $0.05 (best) | $0.10 | $0.10 |
| Blended (3:1) | $2.00 (best) | $4.00 | $4.00 |
| Long-context rate | Over 272K: $2.00 / $7.50 | Same rate | Same rate |
| Price source | Official OpenAI API | Official Anthropic API | Official Google API |
| Limits | |||
| Context window | 1,050,000 tokens (best) | 1,000,000 tokens | 1,048,576 tokens |
| Max output | 128,000 tokens (best) | 128,000 tokens (best) | 65,536 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | No | Yes |
| Video | No | No | Yes |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · medium · high · xhigh · max | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gpt-6.1-terra | claude-sonnet-5-5 | gemini-4-argon |
| API providers | 22 | 34 (best) | 24 |
| Released | Oct 26, 2026 | Sep 28, 2026 | Oct 13, 2026 |
| Knowledge cutoff | Jun 1, 2026 | Jun 2026 | Mar 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-6.1 Terra$20.00
- Claude Sonnet 5.5$40.00
- Gemini 4 Argon$40.00
Which should you choose?
Which is better: GPT-6.1 Terra, Claude Sonnet 5.5 or Gemini 4 Argon?
It is close. Our weighted score puts them within 2 points (GPT-6.1 Terra 76/100, Gemini 4 Argon 74/100, Claude Sonnet 5.5 72/100), so choose by what matters most for your work: GPT-6.1 Terra for raw capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-6.1 Terra, Claude Sonnet 5.5 or Gemini 4 Argon?
GPT-6.1 Terra is cheaper at $1.00 input / $5.00 output per million tokens (official OpenAI API price). Claude Sonnet 5.5 costs $2.00 input / $10.00 output per million tokens (official Anthropic API price); Gemini 4 Argon costs $2.00 input / $10.00 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for GPT-6.1 Terra versus $4.00 for Claude Sonnet 5.5 (2× as much) and $4.00 for Gemini 4 Argon (2× as much).
Which scores higher on benchmarks?
GPT-6.1 Terra scores higher on the Capabilities Index (ECI): GPT-6.1 Terra 168.1 (#3 of 165), Claude Sonnet 5.5 166.7 (#5 of 165) and Gemini 4 Argon 166.1 (#7 of 165). The confidence ranges of the top two overlap (164.9–172.9 vs 163.6–171.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 4 Argon 96.4%, Claude Sonnet 5.5 95.6%, GPT-6.1 Terra 94.3%; FrontierMath Tiers 1–3 — GPT-6.1 Terra 90.9%, Claude Sonnet 5.5 88.8%, Gemini 4 Argon 86.0%; OTIS Mock AIME 2024–2025 — GPT-6.1 Terra 100%, Claude Sonnet 5.5 100%, Gemini 4 Argon 100%; SimpleQA Verified — Gemini 4 Argon 76.0%, GPT-6.1 Terra 57.3%, Claude Sonnet 5.5 46.5%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-6.1 Terra, Claude Sonnet 5.5 and Gemini 4 Argon yet, so there is no like-for-like coding score. On overall capability, GPT-6.1 Terra 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 Terra and Gemini 4 Argon have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for Claude Sonnet 5.5. Maximum output per response: GPT-6.1 Terra up to 128,000, Claude Sonnet 5.5 up to 128,000, Gemini 4 Argon up to 65,536 tokens.
Which can read images, PDFs, audio or video?
GPT-6.1 Terra accepts text, images and PDFs; Claude Sonnet 5.5 accepts text, images and PDFs; Gemini 4 Argon accepts text, images, PDFs, audio and video. Gemini 4 Argon handles the widest range of inputs.
Are any of these open source?
No. GPT-6.1 Terra, Claude Sonnet 5.5 and Gemini 4 Argon are proprietary and only available through APIs and apps.
Which is newer?
GPT-6.1 Terra is the newest, released Oct 26, 2026. Gemini 4 Argon came out Oct 13, 2026; Claude Sonnet 5.5 came out Sep 28, 2026. Knowledge cutoff: GPT-6.1 Terra Jun 1, 2026, Claude Sonnet 5.5 Jun 2026, Gemini 4 Argon Mar 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.
