Claude 3.5 Sonnet vs o3 Deep Research
Claude 3.5 Sonnet (2024) and o3 Deep Research (2026) are frontier-tier reasoning models from Anthropic and OpenAI. Claude 3.5 Sonnet ships a 200K-token context window, while o3 Deep Research ships a 200K-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
o3 Deep Research is safer overall; choose Claude 3.5 Sonnet when coding workflow support matters.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-06-20 | 2026-01-01 |
| Context window | 200K | 200K |
| Parameters | 70B | — |
| Architecture | decoder only | decoder only |
| License | Unknown | Proprietary |
| Knowledge cutoff | 2024-04 | - |
Pricing and availability
| Pricing attribute | Claude 3.5 Sonnet | o3 Deep Research |
|---|---|---|
| Input price | $3/1M tokens | - |
| Output price | $15/1M tokens | - |
| Providers | - |
Capabilities
| Capability | Claude 3.5 Sonnet | o3 Deep Research |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on tool use: o3 Deep Research and code execution: Claude 3.5 Sonnet. Both models share vision, multimodal input, reasoning mode, and function calling, 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.
Pricing coverage is uneven: Claude 3.5 Sonnet has $3/1M input tokens and o3 Deep Research has no token price sourced yet. Provider availability is 6 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Claude 3.5 Sonnet when coding workflow support and broader provider choice are central to the workload. Choose o3 Deep Research when vision-heavy evaluation are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, Claude 3.5 Sonnet or o3 Deep Research?
Claude 3.5 Sonnet supports 200K tokens, while o3 Deep Research supports 200K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Claude 3.5 Sonnet or o3 Deep Research open source?
Claude 3.5 Sonnet is listed under Unknown. o3 Deep Research 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 3.5 Sonnet or o3 Deep Research?
Both Claude 3.5 Sonnet and o3 Deep Research 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 3.5 Sonnet or o3 Deep Research?
Both Claude 3.5 Sonnet and o3 Deep Research expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for reasoning mode, Claude 3.5 Sonnet or o3 Deep Research?
Both Claude 3.5 Sonnet and o3 Deep Research expose reasoning mode. 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 3.5 Sonnet and o3 Deep Research?
Claude 3.5 Sonnet is available on GCP Vertex AI, AWS Bedrock, Anthropic, OpenRouter, and Microsoft Foundry. o3 Deep Research is available on the tracked providers still being sourced. 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.