Claude Opus 5.5 vs Gemini 4 Carbon
Claude Opus 5.5 (2026) and Gemini 4 Carbon (2026) are frontier-tier reasoning models from Anthropic and Google DeepMind. Both ship a 1M-token context window. On Chatbot Arena, Gemini 4 Carbon leads by 19 pts. On pricing, Claude Opus 5.5 costs $4/1M input tokens; Gemini 4 Carbon ranges from $1 to $3.60/1M input tokens by tier. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 4 Carbon is safer overall; choose Claude Opus 5.5 when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | Claude Opus 5.5 | Gemini 4 Carbon |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1M | 1M |
| Cheapest output | $20/1M tokens | $5/1M tokens |
| Provider routes | 5 tracked | 4 tracked |
| Shared benchmarks | 2 shared | Chatbot Arena leader |
Decision tradeoffs
- Claude Opus 5.5 holds a shared-benchmark lead on LMArena Text Arena - Creative Writing, ahead by 3 points.
- Claude Opus 5.5 has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Claude Opus 5.5 for Coding, RAG, and Agents.
- Gemini 4 Carbon holds a shared-benchmark lead on Chatbot Arena, ahead by 19 points.
- Gemini 4 Carbon has the lower cheapest tracked output price at $5/1M tokens.
- Gemini 4 Carbon uniquely exposes Code execution in local model data.
- Local decision data tags Gemini 4 Carbon for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Opus 5.5
$8,200
Cheapest tracked route/tier: Anthropic
Gemini 4 Carbon
$2,050
Cheapest tracked route/tier: Google AI Studio Flex
Estimated monthly gap: $6,150. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on GCP Vertex AI and OpenRouter; start route-level A/B tests there.
- Gemini 4 Carbon is $15/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Gemini 4 Carbon adds Code execution in local capability data.
- Provider overlap exists on GCP Vertex AI and OpenRouter; start route-level A/B tests there.
- Claude Opus 5.5 is $15/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Code execution before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-09-22 | 2026-10-28 |
| Context window | 1M | 1M |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Restricted | Restricted |
| Knowledge cutoff | 2026-06 | 2026-03 |
Pricing and availability
| Pricing attribute | Claude Opus 5.5 | Gemini 4 Carbon |
|---|---|---|
| Input price | $4/1M tokens |
|
| Output price | $20/1M tokens |
|
| Providers |
Capabilities
| Capability | Claude Opus 5.5 | Gemini 4 Carbon |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Opus 5.5 | Gemini 4 Carbon |
|---|---|---|
| Chatbot Arena | 1509.0 | 1528.0 |
| LMArena Text Arena - Creative Writing | 1534.0 | 1531.0 |
Deep dive
On shared benchmark coverage, Chatbot Arena has Claude Opus 5.5 at 1509 and Gemini 4 Carbon at 1528, with Gemini 4 Carbon ahead by 19 points; LMArena Text Arena - Creative Writing has Claude Opus 5.5 at 1534 and Gemini 4 Carbon at 1531, with Claude Opus 5.5 ahead by 3 points. The largest visible gap is 19 points on Chatbot Arena, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on JSON / Tool use: Claude Opus 5.5 and code execution: Gemini 4 Carbon. Both models share vision, multimodal input, reasoning mode, and JSON / Tool use, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Claude Opus 5.5 lists $4/1M input and $20/1M output tokens on the cheapest listed provider, while Gemini 4 Carbon lists tiered pricing: Flex is $1/1M input and $5/1M output; Standard is $2/1M input and $10/1M output; Priority is $3.60/1M input and $18/1M output. A 70/30 input-output blend puts Gemini 4 Carbon lower by about $6.60 per million blended tokens. For tiered pricing, this cheapest-route view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 5 providers versus 4, so concentration risk also matters.
Choose Claude Opus 5.5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose Gemini 4 Carbon when coding workflow support and lower cheapest-tier input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Claude Opus 5.5 or Gemini 4 Carbon?
Claude Opus 5.5 supports 1M tokens, while Gemini 4 Carbon supports 1M tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Opus 5.5 or Gemini 4 Carbon?
Claude Opus 5.5 lists $4/1M input and $20/1M output tokens on the cheapest listed provider. Gemini 4 Carbon lists tiered pricing: Flex is $1/1M input and $5/1M output; Standard is $2/1M input and $10/1M output; Priority is $3.60/1M input and $18/1M output. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 5.5 or Gemini 4 Carbon open source?
Claude Opus 5.5 is listed under Proprietary. Gemini 4 Carbon is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Claude Opus 5.5 or Gemini 4 Carbon?
Both Claude Opus 5.5 and Gemini 4 Carbon expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Claude Opus 5.5 or Gemini 4 Carbon?
Both Claude Opus 5.5 and Gemini 4 Carbon expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Claude Opus 5.5 and Gemini 4 Carbon?
Claude Opus 5.5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, Microsoft Foundry, and OpenRouter. Gemini 4 Carbon is available on Google AI Studio, GCP Vertex AI, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-11-10. Data sourced from public model cards and provider documentation.