Claude Opus 5.5 vs GPT-6.1 Sol
Claude Opus 5.5 (2026) and GPT-6.1 Sol (2026) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Opus 5.5 ships a 1M-token context window, while GPT-6.1 Sol ships a 1.05M-token context window. On Google-Proof Q&A, GPT-6.1 Sol leads by 4.8 pts. On pricing, GPT-6.1 Sol costs $2/1M input tokens versus $4/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GPT-6.1 Sol is ~100% cheaper at $2/1M; pay for Claude Opus 5.5 only for vision-heavy evaluation.
Decision scorecard
Local evidence first| Signal | Claude Opus 5.5 | GPT-6.1 Sol |
|---|---|---|
| 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 | 1.05M |
| Cheapest output | $20/1M tokens | $10/1M tokens |
| Provider routes | 5 tracked | 3 tracked |
| Shared benchmarks | 4 shared | Google-Proof Q&A leader |
Decision tradeoffs
- Claude Opus 5.5 holds a shared-benchmark lead on FrontierCode 1.1 Main, ahead by 4.4 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.
- GPT-6.1 Sol holds a shared-benchmark lead on Google-Proof Q&A, ahead by 4.8 points.
- GPT-6.1 Sol has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-6.1 Sol has the lower cheapest tracked output price at $10/1M tokens.
- GPT-6.1 Sol uniquely exposes Code execution in local model data.
- Local decision data tags GPT-6.1 Sol 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
GPT-6.1 Sol
$4,100
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $4,100. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- GPT-6.1 Sol is $10/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- GPT-6.1 Sol adds Code execution in local capability data.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Claude Opus 5.5 is $10/1M 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 | 2026-09-29 |
| Context window | 1M | 1.05M |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2026-06 | 2026-04 |
Pricing and availability
| Pricing attribute | Claude Opus 5.5 | GPT-6.1 Sol |
|---|---|---|
| Input price | $4/1M tokens | $2/1M tokens |
| Output price | $20/1M tokens | $10/1M tokens |
| Providers |
Capabilities
| Capability | Claude Opus 5.5 | GPT-6.1 Sol |
|---|---|---|
| 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 | GPT-6.1 Sol |
|---|---|---|
| Google-Proof Q&A | 90.6 | 95.4 |
| FrontierMath Tier 4 | 95.0 | 100.0 |
| FrontierCode 1.1 Main | 54.6 | 50.2 |
| ARC-AGI-2 | 93.3 | 94.2 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Claude Opus 5.5 at 90.6 and GPT-6.1 Sol at 95.4, with GPT-6.1 Sol ahead by 4.8 points; FrontierMath Tier 4 has Claude Opus 5.5 at 95 and GPT-6.1 Sol at 100, with GPT-6.1 Sol ahead by 5 points; FrontierCode 1.1 Main has Claude Opus 5.5 at 54.6 and GPT-6.1 Sol at 50.2, with Claude Opus 5.5 ahead by 4.4 points. The largest visible gap is 5 points on FrontierMath Tier 4, 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 code execution: GPT-6.1 Sol. 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 tracked provider, while GPT-6.1 Sol lists $2/1M input and $10/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-6.1 Sol lower by about $4.40 per million blended tokens. Availability is 5 providers versus 3, so concentration risk also matters.
Choose Claude Opus 5.5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose GPT-6.1 Sol when coding workflow support, larger context windows, and lower 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 GPT-6.1 Sol?
GPT-6.1 Sol supports 1.05M tokens, while Claude Opus 5.5 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 GPT-6.1 Sol?
GPT-6.1 Sol is cheaper on tracked token pricing. Claude Opus 5.5 costs $4/1M input and $20/1M output tokens. GPT-6.1 Sol costs $2/1M input and $10/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 5.5 or GPT-6.1 Sol open source?
Claude Opus 5.5 is listed under Proprietary. GPT-6.1 Sol 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 GPT-6.1 Sol?
Both Claude Opus 5.5 and GPT-6.1 Sol expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Claude Opus 5.5 or GPT-6.1 Sol?
Both Claude Opus 5.5 and GPT-6.1 Sol 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 GPT-6.1 Sol?
Claude Opus 5.5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, Microsoft Foundry, and OpenRouter. GPT-6.1 Sol is available on OpenAI API, Azure OpenAI, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-10-16. Data sourced from public model cards and provider documentation.