GPT-5.5 vs Gemini 3.1 Pro Preview vs Claude Opus 4.8
Gemini 3.1 Pro Preview comes out ahead, 68 to 63 and 63 on our weighted score, and it is the cheaper option too.
OpenAIGPT-5.5
63/100- ECI159.2
- Price$5.00 / $30.00
- Context1.05M
- Our pick
GoogleGemini 3.1 Pro Preview
68/100- ECI154.8
- Price$2.00 / $12.00
- Context1.05M
AnthropicClaude Opus 4.8
63/100- ECI158.3
- Price$5.00 / $25.00
- Context1M
Gemini 3.1 Pro Preview is our pick
Gemini 3.1 Pro Preview is the better all-round choice, scoring 68/100 against GPT-5.5 (63) and Claude Opus 4.8 (63). It leads on price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-5.5Capabilities Index (ECI): GPT-5.5 159.2 · Claude Opus 4.8 158.3 · Gemini 3.1 Pro Preview 154.8
- Lowest priceGemini 3.1 Pro PreviewGemini 3.1 Pro Preview $4.50 · Claude Opus 4.8 $10.00 · GPT-5.5 $11.25 per 1M tokens (3:1 blend)
- Longest contextGPT-5.5 and Gemini 3.1 Pro PreviewGPT-5.5 1,050,000 · Gemini 3.1 Pro Preview 1,048,576 · Claude Opus 4.8 1,000,000 tokens
- Widest inputsGemini 3.1 Pro PreviewGPT-5.5: Text, Images, PDFs · Gemini 3.1 Pro Preview: Text, Images, PDFs, Audio, Video · Claude Opus 4.8: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | GPT-5.5 | Gemini 3.1 Pro Preview | Claude Opus 4.8 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 90 | 84 | 89 |
| Price | 25% | 0 | 19 | 2 |
| Inputs & features | 15% | 80 | 100 | 80 |
| Context window | 10% | 61 | 61 | 60 |
| Overall | 100% | 63/100 | 68/100 | 63/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.5OpenAI | Gemini 3.1 Pro PreviewGoogle | Claude Opus 4.8Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 159.2 (best) | 154.8 | 158.3 |
| ECI rank | #10 of 148 (best) | #31 of 148 | #12 of 148 |
| GPQA DiamondGraduate-level science questions | 94.0% | 94.4% (best) | 91.0% |
| FrontierMath Tiers 1–3Research-level mathematics | 85.3% (best) | 59.7% | 80.0% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 95.6% | 98.3% |
| SWE-bench VerifiedFixing real GitHub issues | 80.6% (best) | 75.6% | — |
| SimpleQA VerifiedShort factual questions | 63.0% | 73.5% (best) | 53.0% |
| Price per million tokens | |||
| Input | $5.00 | $2.00 (best) | $5.00 |
| Output | $30.00 | $12.00 (best) | $25.00 |
| Cached input | $0.50 | $0.20 (best) | $0.50 |
| Blended (3:1) | $11.25 | $4.50 (best) | $10.00 |
| Long-context rate | Over 272K: $10.00 / $45.00 | Over 200K: $4.00 / $18.00 | Same rate |
| Price source | Official OpenAI API | Official Google API | Official Anthropic API |
| Limits | |||
| Context window | 1,050,000 tokens (best) | 1,048,576 tokens | 1,000,000 tokens |
| 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 | 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 | gpt-5.5 | gemini-3.1-pro-preview | claude-opus-4-8 |
| API providers | 42 | 26 | 45 (best) |
| Released | Apr 23, 2026 | Feb 19, 2026 | May 28, 2026 |
| Knowledge cutoff | Dec 1, 2025 | Jan 2025 | Jan 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-5.5$110.00
- Gemini 3.1 Pro Preview$44.00
- Claude Opus 4.8$100.00
Which should you choose?
Which is better: GPT-5.5, Gemini 3.1 Pro Preview or Claude Opus 4.8?
Gemini 3.1 Pro Preview is the better all-round choice, scoring 68/100 against GPT-5.5 (63) and Claude Opus 4.8 (63). It leads on price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.5, Gemini 3.1 Pro Preview or Claude Opus 4.8?
Gemini 3.1 Pro Preview is cheaper at $2.00 input / $12.00 output per million tokens (official Google API price). Claude Opus 4.8 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price); GPT-5.5 costs $5.00 input / $30.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $4.50 per million tokens for Gemini 3.1 Pro Preview versus $10.00 for Claude Opus 4.8 (2.2× as much) and $11.25 for GPT-5.5 (2.5× as much).
Which scores higher on benchmarks?
GPT-5.5 scores higher on the Capabilities Index (ECI): GPT-5.5 159.2 (#10 of 148), Claude Opus 4.8 158.3 (#12 of 148) and Gemini 3.1 Pro Preview 154.8 (#31 of 148). The confidence ranges of the top two overlap (156.9–162.4 vs 156.1–160.7), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 3.1 Pro Preview 94.4%, GPT-5.5 94.0%, Claude Opus 4.8 91.0%; FrontierMath Tiers 1–3 — GPT-5.5 85.3%, Claude Opus 4.8 80.0%, Gemini 3.1 Pro Preview 59.7%; OTIS Mock AIME 2024–2025 — GPT-5.5 100%, Claude Opus 4.8 98.3%, Gemini 3.1 Pro Preview 95.6%; SimpleQA Verified — Gemini 3.1 Pro Preview 73.5%, GPT-5.5 63.0%, Claude Opus 4.8 53.0%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Opus 4.8 yet, so there is no like-for-like coding score. On overall capability, GPT-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-5.5 and Gemini 3.1 Pro Preview have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for Claude Opus 4.8. Maximum output per response: GPT-5.5 up to 128,000, Gemini 3.1 Pro Preview up to 65,536, Claude Opus 4.8 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.5 accepts text, images and PDFs; Gemini 3.1 Pro Preview accepts text, images, PDFs, audio and video; Claude Opus 4.8 accepts text, images and PDFs. Gemini 3.1 Pro Preview handles the widest range of inputs.
Are any of these open source?
No. GPT-5.5, Gemini 3.1 Pro Preview and Claude Opus 4.8 are proprietary and only available through APIs and apps.
Which is newer?
Claude Opus 4.8 is the newest, released May 28, 2026. GPT-5.5 came out Apr 23, 2026; Gemini 3.1 Pro Preview came out Feb 19, 2026. Knowledge cutoff: GPT-5.5 Dec 1, 2025, Gemini 3.1 Pro Preview Jan 2025, Claude Opus 4.8 Jan 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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