Claude Sonnet 5.5 vs Gemini 3 Pro Preview vs GPT-6.1 Sol
Too close to call on our weighted score (GPT-6.1 Sol 72, Claude Sonnet 5.5 72, Gemini 3 Pro Preview 72). The right pick depends on what you value most.
AnthropicClaude Sonnet 5.5
72/100- ECI165.2
- Price$2.00 / $10.00
- Context1M
GoogleGemini 3 Pro Preview
72/100- ECI153.0
- Price$2.00 / $12.00
- Context1.05M
OpenAIGPT-6.1 Sol
72/100- ECI—
- Price$2.00 / $10.00
- Context1.05M
Too close to call
It is close. Our weighted score puts them within a point (GPT-6.1 Sol 72/100, Claude Sonnet 5.5 72/100, Gemini 3 Pro Preview 72/100), so choose by what matters most for your work: Claude Sonnet 5.5 for raw capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because GPT-6.1 Sol has no Capabilities Index score yet.
- CapabilityClaude Sonnet 5.5Shared benchmarks: Claude Sonnet 5.5 97.8% · GPT-6.1 Sol 97.7% · Gemini 3 Pro Preview 92.0%
- Lowest priceClaude Sonnet 5.5 and GPT-6.1 SolClaude Sonnet 5.5 $4.00 · GPT-6.1 Sol $4.00 · Gemini 3 Pro Preview $4.50 per 1M tokens (3:1 blend)
- Longest contextGPT-6.1 Sol and Gemini 3 Pro PreviewGPT-6.1 Sol 1,050,000 · Gemini 3 Pro Preview 1,048,576 · Claude Sonnet 5.5 1,000,000 tokens
- Widest inputsGemini 3 Pro PreviewClaude Sonnet 5.5: Text, Images, PDFs · Gemini 3 Pro Preview: 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 Sonnet 5.5 | Gemini 3 Pro Preview | GPT-6.1 Sol |
|---|---|---|---|---|
| CapabilityShared benchmarks | 50% | 98 | 92 | 98 |
| Price | 25% | 21 | 19 | 21 |
| Inputs & features | 15% | 80 | 100 | 80 |
| Context window | 10% | 60 | 61 | 61 |
| Overall | 100% | 72/100 | 72/100 | 72/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Sonnet 5.5Anthropic | Gemini 3 Pro PreviewGoogle | GPT-6.1 SolOpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 165.2 (best) | 153.0 | — |
| ECI rank | #3 of 148 (best) | #39 of 148 | — |
| GPQA DiamondGraduate-level science questions | 95.6% (best) | 92.6% | 95.4% |
| FrontierMath Tiers 1–3Research-level mathematics | 88.8% | — | 93.7% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 91.4% | 100% (best) |
| SWE-bench VerifiedFixing real GitHub issues | — | 72.9% | — |
| SimpleQA VerifiedShort factual questions | 46.5% | — | 73.9% (best) |
| Price per million tokens | |||
| Input | $2.00 | $2.00 | $2.00 |
| Output | $10.00 (best) | $12.00 | $10.00 (best) |
| Cached input | $0.20 | — | $0.10 (best) |
| Blended (3:1) | $4.00 (best) | $4.50 | $4.00 (best) |
| Long-context rate | Same rate | Same rate | Over 272K: $4.00 / $15.00 |
| Price source | Official Anthropic API | Median of 2 providers | 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 | Yes | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-sonnet-5-5 | — | gpt-6.1-sol |
| API providers | 23 (best) | 3 | 21 |
| Released | Sep 28, 2026 | Nov 18, 2025 | Sep 29, 2026 |
| Knowledge cutoff | Jun 2026 | Jan 2025 | 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 Sonnet 5.5$40.00
- Gemini 3 Pro Preview$44.00
- GPT-6.1 Sol$40.00
Which should you choose?
Which is better: Claude Sonnet 5.5, Gemini 3 Pro Preview or GPT-6.1 Sol?
It is close. Our weighted score puts them within a point (GPT-6.1 Sol 72/100, Claude Sonnet 5.5 72/100, Gemini 3 Pro Preview 72/100), so choose by what matters most for your work: Claude Sonnet 5.5 for raw capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because GPT-6.1 Sol has no Capabilities Index score yet.
Which is cheaper, Claude Sonnet 5.5, Gemini 3 Pro Preview or GPT-6.1 Sol?
Claude Sonnet 5.5 is cheaper at $2.00 input / $10.00 output per million tokens (official Anthropic API price). GPT-6.1 Sol costs $2.00 input / $10.00 output per million tokens (official OpenAI API price); Gemini 3 Pro Preview costs $2.00 input / $12.00 output per million tokens (median across 2 API providers). At a typical mix of three input tokens to one output token, that is $4.00 per million tokens for Claude Sonnet 5.5 versus $4.00 for GPT-6.1 Sol (1× as much) and $4.50 for Gemini 3 Pro Preview (1.1× as much).
Which scores higher on benchmarks?
Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025): Claude Sonnet 5.5 97.8%, GPT-6.1 Sol 97.7% and Gemini 3 Pro Preview 92.0%. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, GPT-6.1 Sol 95.4%, Gemini 3 Pro Preview 92.6%; OTIS Mock AIME 2024–2025 — Claude Sonnet 5.5 100%, GPT-6.1 Sol 100%, Gemini 3 Pro Preview 91.4%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Sonnet 5.5 and GPT-6.1 Sol yet, so there is no like-for-like coding score. On overall capability, Claude Sonnet 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 3 Pro Preview 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: Claude Sonnet 5.5 up to 128,000, Gemini 3 Pro Preview up to 65,536, GPT-6.1 Sol up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Sonnet 5.5 accepts text, images and PDFs; Gemini 3 Pro Preview accepts text, images, PDFs, audio and video; GPT-6.1 Sol accepts text, images and PDFs. Gemini 3 Pro Preview handles the widest range of inputs.
Are any of these open source?
No. Claude Sonnet 5.5, Gemini 3 Pro Preview and GPT-6.1 Sol are proprietary and only available through APIs and apps.
Which is newer?
GPT-6.1 Sol is the newest, released Sep 29, 2026. Claude Sonnet 5.5 came out Sep 28, 2026; Gemini 3 Pro Preview came out Nov 18, 2025. Knowledge cutoff: Claude Sonnet 5.5 Jun 2026, Gemini 3 Pro Preview Jan 2025, 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 Oct 4, 2026.
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