Claude Sonnet 5.5 vs GPT-6.1 Sol
Claude Sonnet 5.5 (2026) and GPT-6.1 Sol (2026) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Sonnet 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, Claude Sonnet 5.5 leads by 0.2 pts. On pricing, both list $2/1M input and $10/1M output tokens on the cheapest tracked route. 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 safer overall; choose Claude Sonnet 5.5 when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 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 | $10/1M tokens | $10/1M tokens |
| Provider routes | 5 tracked | 3 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 3 shared |
Decision tradeoffs
- Claude Sonnet 5.5 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 0.2 points.
- Claude Sonnet 5.5 has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Claude Sonnet 5.5 for Coding, RAG, and Agents.
- GPT-6.1 Sol holds a shared-benchmark lead on FrontierMath Tier 4, ahead by 19.5 points.
- GPT-6.1 Sol has the larger context window for long prompts, retrieval packs, or transcript analysis.
- 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 Sonnet 5.5
$4,100
Cheapest tracked route/tier: Anthropic
GPT-6.1 Sol
$4,100
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $0.00. 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.
- Cheapest tracked output pricing is tied, so migration risk shifts to quality, latency, and provider packaging.
- GPT-6.1 Sol adds Code execution in local capability data.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Cheapest tracked output pricing is tied, so migration risk shifts to quality, latency, and provider packaging.
- Check replacement coverage for Code execution before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-09-28 | 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 Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| Input price | $2/1M tokens | $2/1M tokens |
| Output price | $10/1M tokens | $10/1M tokens |
| Providers |
Capabilities
| Capability | Claude Sonnet 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 Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| Google-Proof Q&A | 95.6 | 95.4 |
| FrontierMath Tier 4 | 80.5 | 100.0 |
| FrontierCode 1.1 Main | 52.1 | 50.2 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Claude Sonnet 5.5 at 95.6 and GPT-6.1 Sol at 95.4, with Claude Sonnet 5.5 ahead by 0.2 points; FrontierMath Tier 4 has Claude Sonnet 5.5 at 80.5 and GPT-6.1 Sol at 100, with GPT-6.1 Sol ahead by 19.5 points; FrontierCode 1.1 Main has Claude Sonnet 5.5 at 52.1 and GPT-6.1 Sol at 50.2, with Claude Sonnet 5.5 ahead by 1.9 points. The largest visible gap is 19.5 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 Sonnet 5.5 lists $2/1M input and $10/1M 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 is tied on the cheapest tracked routes. Availability is 5 providers versus 3, so concentration risk also matters.
Choose Claude Sonnet 5.5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose GPT-6.1 Sol when coding workflow support and larger context windows 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 Sonnet 5.5 or GPT-6.1 Sol?
GPT-6.1 Sol supports 1.05M tokens, while Claude Sonnet 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 Sonnet 5.5 or GPT-6.1 Sol?
Neither is cheaper on tracked token pricing. Both list $2/1M input and $10/1M output tokens on the cheapest tracked route. Provider discounts, batch pricing, or route-specific tiers can still change the final bill.
Is Claude Sonnet 5.5 or GPT-6.1 Sol open source?
Claude Sonnet 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 Sonnet 5.5 or GPT-6.1 Sol?
Both Claude Sonnet 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 Sonnet 5.5 or GPT-6.1 Sol?
Both Claude Sonnet 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 Sonnet 5.5 and GPT-6.1 Sol?
Claude Sonnet 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.