AI model comparison
Claude Opus 5.5 vs Gemini 3.1 Pro Preview
Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.
Anthropic
Claude Opus 5.5
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.
- Input / 1M
- $4
- Output / 1M
- $20
- Context
- 1M
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview is Google’s frontier reasoning model, delivering enhanced software engineering performance, improved agentic reliability, and more efficient token usage across complex workflows.
- Input / 1M
- $2
- Output / 1M
- $12
- Context
- 1.05M
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
Gemini 3.1 Pro Preview
1.8x cheaper for a typical chat
Higher intelligence score
Claude Opus 5.5
57.6 vs 29.7 on Artificial Analysis
Larger context window
Gemini 3.1 Pro Preview
1.05M vs 1M tokens
Newer release
Claude Opus 5.5
Released September 22, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
Claude Opus 5.557.6Gemini 3.1 Pro Preview29.7Coding index
Claude Opus 5.5Not availableGemini 3.1 Pro Preview68.8Agentic index
Claude Opus 5.5Not availableGemini 3.1 Pro Preview8.2Pricing
Claude Opus 5.5 vs Gemini 3.1 Pro Preview API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| Input tokensPer 1M tokens | $4 | $2 |
| Output tokensPer 1M tokens | $20 | $12 |
| Cached input (read)Per 1M tokens | $0.20 | $0.20 |
| Cache writePer 1M tokens | $5 | $0.38 |
| Long-context pricingPer 1M tokens, for very long prompts | Same rate at any length | $4 in / $18 out above 200K |
| Web searchPer request | $0.01 | $0.014 |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
Claude Opus 5.5$18Gemini 3.1 Pro Preview$10Coding task
30K in, 4K out
Claude Opus 5.5$200$86 cachedGemini 3.1 Pro Preview$108$54 cachedLong document summary
150K in, 2K out
Claude Opus 5.5$640$70 cachedGemini 3.1 Pro Preview$324$54 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| Context window | 1M tokens | 1.05M tokens |
| Max output | 128K tokens | 66K tokens |
| Input types | File, Image, Text | Audio, File, Image, Text, Video |
| Output types | Text | Text |
| Reasoning effort levels | Max, Extra high, High, Medium, Low | High, Medium, Low |
| Default reasoning effort | High | Medium |
| Release date | September 22, 2026 | February 19, 2026 |
Features
Supported features
API features available for each model.
| Metric | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Not supported | Supported |
| Stop sequences | Supported | Supported |
| Deterministic seed | Not supported | Supported |
| Verbosity control | Supported | Not supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
Claude Opus 5.5View full model details- Claude Opus 5.5 vs Claude Sonnet 5.5
- Claude Opus 5.5 vs Claude Fable 5.1
- Claude Opus 5.5 vs GPT-6 Astra
- Claude Opus 5.5 vs GPT-6.1 Sol
- Claude Opus 5.5 vs Claude Opus 5
- Claude Opus 5.5 vs Claude Fable 5
- Claude Opus 5.5 vs DeepSeek V4.1 Flash
- Claude Opus 5.5 vs Muse Spark 1.3
- Claude Opus 5.5 vs GLM 5.3 Flash
- Claude Opus 5.5 vs GPT-6 Sol
- Claude Opus 5.5 vs MiMo-V2.6-Flash
- Claude Opus 5.5 vs GPT-5.6 Sol
- Claude Opus 5.5 vs Hy4 preview
- Claude Opus 5.5 vs Grok 4.7
- Claude Opus 5.5 vs GPT-6 Luna
- Claude Opus 5.5 vs DeepSeek V4 Flash 0731
- Claude Opus 5.5 vs GLM 5.3
- Claude Opus 5.5 vs Kimi K3
- Claude Opus 5.5 vs DeepSeek V4 Flash 0423
- Claude Opus 5.5 vs Step 5 Preview
- Claude Opus 5.5 vs Gemini 3.8 Flash
- Claude Opus 5.5 vs Hy3
Gemini 3.1 Pro PreviewView full model details- Gemini 3.1 Pro Preview vs GPT-6 Astra
- Gemini 3.1 Pro Preview vs GLM 5.2
- Gemini 3.1 Pro Preview vs Gemini 3.5 Flash
- Gemini 3.1 Pro Preview vs GPT-5.3-Codex
- Gemini 3.1 Pro Preview vs Gemini 3 Flash Preview
- Gemini 3.1 Pro Preview vs Claude Opus 4.6
- Gemini 3.1 Pro Preview vs GPT-5.2
- Gemini 3.1 Pro Preview vs Claude Sonnet 4.6
- Gemini 3.1 Pro Preview vs Qwen3.7 Max
- Gemini 3.1 Pro Preview vs Claude Opus 4.5
- Gemini 3.1 Pro Preview vs GPT-5.2-Codex
Our take
Opus 5.5 wins this one on the numbers that matter: it scores far higher on independent intelligence tests (57.6 vs 29.7) and is cheaper on output. Gemini 3.1 Pro is the fallback when you want Google's ecosystem, Search grounding, or a model that is still labeled preview.
FAQ
Frequently asked questions
Is Claude Opus 5.5 or Gemini 3.1 Pro Preview cheaper?
Gemini 3.1 Pro Preview is cheaper for a typical chat (2K input tokens and 500 output tokens). Gemini 3.1 Pro Preview costs $2 per 1M input tokens and $12 per 1M output tokens, while Claude Opus 5.5 costs $4 per 1M input tokens and $20 per 1M output tokens.
Which has a bigger context window, Claude Opus 5.5 or Gemini 3.1 Pro Preview?
Gemini 3.1 Pro Preview supports up to 1.05M tokens of context, compared with 1M for Claude Opus 5.5.
Is Claude Opus 5.5 smarter than Gemini 3.1 Pro Preview?
On the Artificial Analysis Intelligence Index, Claude Opus 5.5 scores 57.6 and Gemini 3.1 Pro Preview scores 29.7, putting Claude Opus 5.5 ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.
Can I use Claude Opus 5.5 and Gemini 3.1 Pro Preview at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Claude Opus 5.5 and Gemini 3.1 Pro Preview answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Claude Opus 5.5 and Gemini 3.1 Pro Preview at the same time. Compare the answers side by side and keep the best one.