Claude Sonnet 5.5 vs Gemini 3 Pro Preview
Claude Sonnet 5.5 comes out ahead, 72 to 67 on our weighted score, and it is the cheaper option too.
- Our pick
AnthropicClaude Sonnet 5.5
72/100- ECI165.2
- Price$2.00 / $10.00
- Context1M
GoogleGemini 3 Pro Preview
67/100- ECI153.0
- Price$2.00 / $12.00
- Context1.05M
Add a model
Make it a three-way comparison.
Claude Sonnet 5.5 is our pick
Claude Sonnet 5.5 is the better all-round choice, scoring 72/100 against Gemini 3 Pro Preview (67). It leads on capability and price. Gemini 3 Pro Preview wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Sonnet 5.5Capabilities Index (ECI): Claude Sonnet 5.5 165.2 · Gemini 3 Pro Preview 153.0
- Lowest priceClaude Sonnet 5.5Claude Sonnet 5.5 $4.00 · Gemini 3 Pro Preview $4.50 per 1M tokens (3:1 blend)
- Longest contextGemini 3 Pro PreviewGemini 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
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | Claude Sonnet 5.5 | Gemini 3 Pro Preview |
|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 97 | 82 |
| Price | 25% | 21 | 19 |
| Inputs & features | 15% | 80 | 100 |
| Context window | 10% | 60 | 61 |
| Overall | 100% | 72/100 | 67/100 |
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 |
|---|---|---|
| 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% |
| FrontierMath Tiers 1–3Research-level mathematics | 88.8% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 91.4% |
| SWE-bench VerifiedFixing real GitHub issues | — | 72.9% |
| SimpleQA VerifiedShort factual questions | 46.5% | — |
| Price per million tokens | ||
| Input | $2.00 | $2.00 |
| Output | $10.00 (best) | $12.00 |
| Cached input | $0.20 | — |
| Blended (3:1) | $4.00 (best) | $4.50 |
| Long-context rate | Same rate | Same rate |
| Price source | Official Anthropic API | Median of 2 providers |
| Limits | ||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) |
| Max output | 128,000 tokens (best) | 65,536 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | Yes | Yes |
| Audio | No | Yes |
| Video | No | Yes |
| Reasoning | Yeslow · medium · high · xhigh · max | Yes |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | claude-sonnet-5-5 | — |
| API providers | 23 (best) | 3 |
| Released | Sep 28, 2026 | Nov 18, 2025 |
| Knowledge cutoff | Jun 2026 | Jan 2025 |
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
Which should you choose?
Which is better: Claude Sonnet 5.5 or Gemini 3 Pro Preview?
Claude Sonnet 5.5 is the better all-round choice, scoring 72/100 against Gemini 3 Pro Preview (67). It leads on capability and price. Gemini 3 Pro Preview wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Sonnet 5.5 or Gemini 3 Pro Preview?
Claude Sonnet 5.5 is cheaper at $2.00 input / $10.00 output per million tokens (official Anthropic 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 $4.50 for Gemini 3 Pro Preview (1.1× as much).
Which scores higher on benchmarks?
Claude Sonnet 5.5 scores higher on the Capabilities Index (ECI): Claude Sonnet 5.5 165.2 (#3 of 148) and Gemini 3 Pro Preview 153.0 (#39 of 148). Their confidence ranges do not overlap (161.8–169.4 vs 150.6–155.2), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, Gemini 3 Pro Preview 92.6%; OTIS Mock AIME 2024–2025 — Claude Sonnet 5.5 100%, Gemini 3 Pro Preview 91.4%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Sonnet 5.5 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. Both support tool calling for agent workflows.
Which has the bigger context window?
Gemini 3 Pro Preview has the largest context window at 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 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. Gemini 3 Pro Preview handles the widest range of inputs.
Are any of these open source?
No. Claude Sonnet 5.5 and Gemini 3 Pro Preview are proprietary and only available through APIs and apps.
Which is newer?
Claude Sonnet 5.5 is the newest, released 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.
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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