Gemini 3.1 Pro Preview vs Gemini 3.5 Flash vs Claude Opus 4.6
Too close to call on our weighted score (Gemini 3.5 Flash 69, Gemini 3.1 Pro Preview 68, Claude Opus 4.6 61). The right pick depends on what you value most.
GoogleGemini 3.1 Pro Preview
68/100- ECI154.8
- Price$2.00 / $12.00
- Context1.05M
- Google
Gemini 3.5 Flash
69/100- ECI154.5
- Price$1.50 / $9.00
- Context1.05M
AnthropicClaude Opus 4.6
61/100- ECI155.3
- Price$5.00 / $25.00
- Context1M
Too close to call
It is close. Our weighted score puts them within 1 points (Gemini 3.5 Flash 69/100, Gemini 3.1 Pro Preview 68/100, Claude Opus 4.6 61/100), so choose by what matters most for your work: Claude Opus 4.6 for raw capability and Gemini 3.5 Flash on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Opus 4.6Capabilities Index (ECI): Claude Opus 4.6 155.3 · Gemini 3.1 Pro Preview 154.8 · Gemini 3.5 Flash 154.5
- Lowest priceGemini 3.5 FlashGemini 3.5 Flash $3.38 · Gemini 3.1 Pro Preview $4.50 · Claude Opus 4.6 $10.00 per 1M tokens (3:1 blend)
- Longest contextGemini 3.1 Pro Preview and Gemini 3.5 FlashGemini 3.1 Pro Preview 1,048,576 · Gemini 3.5 Flash 1,048,576 · Claude Opus 4.6 1,000,000 tokens
- Widest inputsGemini 3.1 Pro Preview and Gemini 3.5 FlashGemini 3.1 Pro Preview: Text, Images, PDFs, Audio, Video · Gemini 3.5 Flash: Text, Images, PDFs, Audio, Video · Claude Opus 4.6: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Gemini 3.1 Pro Preview | Gemini 3.5 Flash | Claude Opus 4.6 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 84 | 85 |
| Price | 25% | 19 | 25 | 2 |
| Inputs & features | 15% | 100 | 100 | 80 |
| Context window | 10% | 61 | 61 | 60 |
| Overall | 100% | 68/100 | 69/100 | 61/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Gemini 3.1 Pro PreviewGoogle | Gemini 3.5 FlashGoogle | Claude Opus 4.6Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 154.8 | 154.5 | 155.3 (best) |
| ECI rank | #31 of 148 | #33 of 148 | #27 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 94.4% (best) | 92.8% | 90.5% |
| FrontierMath Tiers 1–3Research-level mathematics | 59.7% | 62.8% | 66.0% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 95.6% (best) | 95.6% | 94.4% |
| SWE-bench VerifiedFixing real GitHub issues | 75.6% | 79.3% (best) | 78.7% |
| SimpleQA VerifiedShort factual questions | 73.5% (best) | 66.2% | 47.0% |
| Price per million tokens | |||
| Input | $2.00 | $1.50 (best) | $5.00 |
| Output | $12.00 | $9.00 (best) | $25.00 |
| Cached input | $0.20 | $0.15 (best) | $0.50 |
| Blended (3:1) | $4.50 | $3.38 (best) | $10.00 |
| Long-context rate | Over 200K: $4.00 / $18.00 | Same rate | Same rate |
| Price source | Official Google API | Official Google API | Official Anthropic API |
| Limits | |||
| Context window | 1,048,576 tokens (best) | 1,048,576 tokens (best) | 1,000,000 tokens |
| Max output | 65,536 tokens | 65,536 tokens | 128,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | Yes | Yes | No |
| Video | Yes | Yes | No |
| Reasoning | Yeslow · medium · high | Yesminimal · low · medium · high | Yeslow · medium · high · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gemini-3.1-pro-preview | gemini-3.5-flash | claude-opus-4-6 |
| API providers | 26 | 32 | 33 (best) |
| Released | Feb 19, 2026 | May 19, 2026 | Feb 5, 2026 |
| Knowledge cutoff | Jan 2025 | Jan 2025 | May 31, 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Gemini 3.1 Pro Preview$44.00
- Gemini 3.5 Flash$33.00
- Claude Opus 4.6$100.00
Which should you choose?
Which is better: Gemini 3.1 Pro Preview, Gemini 3.5 Flash or Claude Opus 4.6?
It is close. Our weighted score puts them within 1 points (Gemini 3.5 Flash 69/100, Gemini 3.1 Pro Preview 68/100, Claude Opus 4.6 61/100), so choose by what matters most for your work: Claude Opus 4.6 for raw capability and Gemini 3.5 Flash on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Gemini 3.1 Pro Preview, Gemini 3.5 Flash or Claude Opus 4.6?
Gemini 3.5 Flash is cheaper at $1.50 input / $9.00 output per million tokens (official Google API price). Gemini 3.1 Pro Preview costs $2.00 input / $12.00 output per million tokens (official Google API price); Claude Opus 4.6 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $3.38 per million tokens for Gemini 3.5 Flash versus $4.50 for Gemini 3.1 Pro Preview (1.3× as much) and $10.00 for Claude Opus 4.6 (3× as much).
Which scores higher on benchmarks?
Claude Opus 4.6 scores higher on the Capabilities Index (ECI): Claude Opus 4.6 155.3 (#27 of 148), Gemini 3.1 Pro Preview 154.8 (#31 of 148) and Gemini 3.5 Flash 154.5 (#33 of 148). The confidence ranges of the top two overlap (153.4–157.3 vs 152.6–157.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 3.1 Pro Preview 94.4%, Gemini 3.5 Flash 92.8%, Claude Opus 4.6 90.5%; FrontierMath Tiers 1–3 — Claude Opus 4.6 66.0%, Gemini 3.5 Flash 62.8%, Gemini 3.1 Pro Preview 59.7%; OTIS Mock AIME 2024–2025 — Gemini 3.1 Pro Preview 95.6%, Gemini 3.5 Flash 95.6%, Claude Opus 4.6 94.4%; SWE-bench Verified — Gemini 3.5 Flash 79.3%, Claude Opus 4.6 78.7%, Gemini 3.1 Pro Preview 75.6%; SimpleQA Verified — Gemini 3.1 Pro Preview 73.5%, Gemini 3.5 Flash 66.2%, Claude Opus 4.6 47.0%.
Which is better for coding?
Gemini 3.5 Flash resolves more real GitHub issues on SWE-bench Verified: Gemini 3.5 Flash 79.3%, Claude Opus 4.6 78.7% and Gemini 3.1 Pro Preview 75.6%. All three support tool calling for agent workflows.
Which has the bigger context window?
Gemini 3.1 Pro Preview and Gemini 3.5 Flash have the largest context windows (1,048,576 and 1,048,576 tokens), against 1,000,000 for Claude Opus 4.6. Maximum output per response: Gemini 3.1 Pro Preview up to 65,536, Gemini 3.5 Flash up to 65,536, Claude Opus 4.6 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Gemini 3.1 Pro Preview accepts text, images, PDFs, audio and video; Gemini 3.5 Flash accepts text, images, PDFs, audio and video; Claude Opus 4.6 accepts text, images and PDFs. Gemini 3.1 Pro Preview handles the widest range of inputs.
Are any of these open source?
No. Gemini 3.1 Pro Preview, Gemini 3.5 Flash and Claude Opus 4.6 are proprietary and only available through APIs and apps.
Which is newer?
Gemini 3.5 Flash is the newest, released May 19, 2026. Gemini 3.1 Pro Preview came out Feb 19, 2026; Claude Opus 4.6 came out Feb 5, 2026. Knowledge cutoff: Gemini 3.1 Pro Preview Jan 2025, Gemini 3.5 Flash Jan 2025, Claude Opus 4.6 May 31, 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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