Claude Sonnet 4.6 vs o3
Claude Sonnet 4.6 (2026) and o3 (2025) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Sonnet 4.6 ships a 1M-token context window, while o3 ships a 200K-token context window. On SWE-bench Verified, Claude Sonnet 4.6 leads by 7.9 pts. On pricing, o3 costs $2/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
o3 is ~50% cheaper at $2/1M; pay for Claude Sonnet 4.6 only for coding workflow support.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-17 | 2025-03-31 |
| Context window | 1M | 200K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.6 | o3 |
|---|---|---|
| Input price | $3/1M tokens | $2/1M tokens |
| Output price | $15/1M tokens | $8/1M tokens |
| Providers |
Capabilities
| Capability | Claude Sonnet 4.6 | o3 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
| Benchmark | Claude Sonnet 4.6 | o3 |
|---|---|---|
| SWE-bench Verified | 79.6 | 71.7 |
| Google-Proof Q&A | 89.9 | 87.7 |
| Chatbot Arena | 1459.0 | 1412.0 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Claude Sonnet 4.6 at 79.6 and o3 at 71.7, with Claude Sonnet 4.6 ahead by 7.9 points; Google-Proof Q&A has Claude Sonnet 4.6 at 89.9 and o3 at 87.7, with Claude Sonnet 4.6 ahead by 2.2 points; Chatbot Arena has Claude Sonnet 4.6 at 1459 and o3 at 1412, with Claude Sonnet 4.6 ahead by 47 points. The largest visible gap is 47 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 vision: Claude Sonnet 4.6, multimodal input: Claude Sonnet 4.6, function calling: Claude Sonnet 4.6, and tool use: Claude Sonnet 4.6. Both models share reasoning mode, structured outputs, and code execution, 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 4.6 lists $3/1M input and $15/1M output tokens, while o3 lists $2/1M input and $8/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts o3 lower by about $2.8 per million blended tokens. Availability is 4 providers versus 2, so concentration risk also matters.
Choose Claude Sonnet 4.6 when coding workflow support, larger context windows, and broader provider choice are central to the workload. Choose o3 when coding workflow support 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 Sonnet 4.6 or o3?
Claude Sonnet 4.6 supports 1M tokens, while o3 supports 200K 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 4.6 or o3?
o3 is cheaper on tracked token pricing. Claude Sonnet 4.6 costs $3/1M input and $15/1M output tokens. o3 costs $2/1M input and $8/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Sonnet 4.6 or o3 open source?
Claude Sonnet 4.6 is listed under Proprietary. o3 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 4.6 or o3?
Claude Sonnet 4.6 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Claude Sonnet 4.6 or o3?
Claude Sonnet 4.6 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Claude Sonnet 4.6 and o3?
Claude Sonnet 4.6 is available on OpenRouter, Anthropic, AWS Bedrock, and GCP Vertex AI. o3 is available on OpenAI API and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.