Claude Opus 5.5 vs Gemini 3.1 Pro — Price, Context, and Capability Compared
Claude Opus 5.5 vs Gemini 3.1 Pro: which should I use?
Claude Opus 5.5 costs 1.8× more per blended million tokens than Gemini 3.1 Pro. Gemini 3.1 Pro has the larger context window (2,000,000 tokens). Default to Gemini 3.1 Pro unless you specifically need Claude Opus 5.5's edge.
Where can you find price, speed, and task evidence for Claude Opus 5.5 and Gemini 3.1 Pro?
Which tasks fit Claude Opus 5.5 and Gemini 3.1 Pro?
Best-fit task signals from the published model strengths; this is not a substitute for a controlled benchmark.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| Best fit | The hardest reasoning, coding, and long-horizon agentic tasks. | Whole-codebase, whole-document, or long-video analysis in a single request. |
| Reasoning mode | Available | Available |
What does a Coding Agent workload cost with Claude Opus 5.5 and Gemini 3.1 Pro?
Modeled for Coding Agent: 20,000 input + 2,000 output tokens per task, 1 turn. This is a workload model, not a provider quote.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| Coding Agent / task | $0.12 (modeled) | $0.06 (modeled) (winner) |
| Input / output rate | $4.00 / $20.00 per M | $2.00 / $12.00 per M |
How fast are Claude Opus 5.5 and Gemini 3.1 Pro?
Only non-estimated benchmark results are shown as measured.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| Measured throughput | Unavailable | 55 tokens/s |
| Time to first token | Unavailable | 420 ms |
How compatible are Claude Opus 5.5 and Gemini 3.1 Pro with APIs?
Provider-level wire-format and SDK facts; model-specific parameter differences may still apply.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| OpenAI SDK | Not drop-in | Not drop-in |
| Request shape | Messages API — system prompt is a top-level field, not a message role, and max_tokens is required on every call. | contents/parts structure instead of messages; an OpenAI-compatible endpoint exists but only covers a subset of parameters. |
| Streaming | SSE (Anthropic content-block events) | SSE (Gemini streamGenerateContent) |
What are the privacy and retention policies for Claude Opus 5.5 and Gemini 3.1 Pro?
Provider policy and residency facts from the verified provider registry. A missing retention policy is not treated as a guarantee.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| Provider says API data trains models | No | No |
| Published retention period | Unavailable | Unavailable |
| Data residency | Unavailable | Global by default; Vertex AI offers selectable regional endpoints |
How much effort does it take to migrate between Claude Opus 5.5 and Gemini 3.1 Pro?
Direction is from each displayed model to the other. Effort is derived from provider compatibility and published parameter maps.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| Move Claude Opus 5.5 → Gemini 3.1 Pro | code-change; 1 breaking parameter difference | Target: Gemini 3.1 Pro |
| Move Gemini 3.1 Pro → Claude Opus 5.5 | Source: Gemini 3.1 Pro | code-change; 7 breaking parameter differences |
| Why | contents/parts structure instead of messages; an OpenAI-compatible endpoint exists but only covers a subset of parameters. | Messages API — system prompt is a top-level field, not a message role, and max_tokens is required on every call. |
How do Claude Opus 5.5 and Gemini 3.1 Pro compare on specs?
| Claude Opus 5.5 | Gemini 3.1 Pro | |
|---|---|---|
| Price (input) | $4.00/M | $2.00/M ✓ |
| Price (output) | $20.00/M | $12.00/M ✓ |
| Blended price | $8.00/M | $4.50/M ✓ |
| Context window | 1,000,000 tokens | 2,000,000 tokens ✓ |
| Max output | 128,000 tokens ✓ | 64,000 tokens |
| Modalities | text, vision | text, vision, audio |
| Reasoning mode | Yes | Yes |
| Released | 2026-09 | 2026-02 |
| Speed | Not measured | 55 t/s |
How much do Claude Opus 5.5 and Gemini 3.1 Pro cost at scale?
| Tokens / month | Claude Opus 5.5 | Gemini 3.1 Pro | Delta |
|---|---|---|---|
| 1,000,000 | $8.00 | $4.50 | $3.50 (1.8×) |
| 10,000,000 | $80.00 | $45.00 | $35.00 (1.8×) |
| 100,000,000 | $800.00 | $450.00 | $350.00 (1.8×) |
Choose Claude Opus 5.5 if…
- ✓Anthropic's strongest reasoning and coding
- ✓1M-token context
- ✓Extended-thinking mode for complex agentic work
- ✓The hardest reasoning, coding, and long-horizon agentic tasks.
Choose Gemini 3.1 Pro if…
- ✓Largest context window of any current model (2M tokens)
- ✓Native audio and video understanding
- ✓Google Search grounding
- ✓Whole-codebase, whole-document, or long-video analysis in a single request.
Run this exact matchup right now
Send the same prompt to Claude Opus 5.5 and Gemini 3.1 Pro side by side and see the outputs yourself.
Try Claude Opus 5.5 vs Gemini 3.1 Pro FreeWhat are common questions about Claude Opus 5.5 and Gemini 3.1 Pro?
Is Claude Opus 5.5 cheaper than Gemini 3.1 Pro?
Gemini 3.1 Pro is cheaper, at $4.50 per million blended tokens vs $8.00 for Claude Opus 5.5.
Which has the bigger context window, Claude Opus 5.5 or Gemini 3.1 Pro?
Gemini 3.1 Pro has the larger context window: 2,000,000 tokens vs 1,000,000.
Can Claude Opus 5.5 replace Gemini 3.1 Pro for coding?
Both are viable for coding. Anthropic's strongest reasoning and coding (Claude Opus 5.5) vs Largest context window of any current model (2M tokens) (Gemini 3.1 Pro) — pick based on which strength matters more for your workload.
Neither of these? See Claude Opus 5.5 alternatives or Gemini 3.1 Pro alternatives.
What related comparisons help choose between Claude Opus 5.5 and Gemini 3.1 Pro?
Pricing verified 2026-04-06. Specs verified 2026-08-14.