Claude 3.5 Sonnet vs o3 Mini
Claude 3.5 Sonnet (2024) and o3 Mini (2025) are frontier-tier reasoning models from Anthropic and OpenAI. Claude 3.5 Sonnet ships a 200K-token context window, while o3 Mini ships a 200K-token context window. On MMLU PRO, o3 Mini leads by 1.9 pts. On pricing, o3 Mini costs $1.1/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
o3 Mini is ~173% cheaper at $1.1/1M; pay for Claude 3.5 Sonnet only for coding workflow support.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-06-20 | 2025-03-31 |
| Context window | 200K | 200K |
| Parameters | 70B | — |
| Architecture | decoder only | decoder only |
| License | Unknown | Proprietary |
| Knowledge cutoff | 2024-04 | 2025-04 |
Pricing and availability
| Pricing attribute | Claude 3.5 Sonnet | o3 Mini |
|---|---|---|
| Input price | $3/1M tokens | $1.1/1M tokens |
| Output price | $15/1M tokens | $4.4/1M tokens |
| Providers |
Capabilities
| Capability | Claude 3.5 Sonnet | o3 Mini |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
Benchmarks
| Benchmark | Claude 3.5 Sonnet | o3 Mini |
|---|---|---|
| MMLU PRO | 77.2 | 79.1 |
| Aider Polyglot | 51.6 | 60.4 |
| Chatbot Arena | 1340.0 | 1335.0 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude 3.5 Sonnet at 77.2 and o3 Mini at 79.1, with o3 Mini ahead by 1.9 points; Aider Polyglot has Claude 3.5 Sonnet at 51.6 and o3 Mini at 60.4, with o3 Mini ahead by 8.8 points; Chatbot Arena has Claude 3.5 Sonnet at 1340 and o3 Mini at 1335, with Claude 3.5 Sonnet ahead by 5 points. The largest visible gap is 8.8 points on Aider Polyglot, 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 3.5 Sonnet, multimodal input: Claude 3.5 Sonnet, and tool use: o3 Mini. Both models share reasoning mode, function calling, 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 3.5 Sonnet lists $3/1M input and $15/1M output tokens, while o3 Mini lists $1.1/1M input and $4.4/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts o3 Mini lower by about $4.51 per million blended tokens. Availability is 6 providers versus 3, so concentration risk also matters.
Choose Claude 3.5 Sonnet when coding workflow support and broader provider choice are central to the workload. Choose o3 Mini 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 3.5 Sonnet or o3 Mini?
Claude 3.5 Sonnet supports 200K tokens, while o3 Mini 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 3.5 Sonnet or o3 Mini?
o3 Mini is cheaper on tracked token pricing. Claude 3.5 Sonnet costs $3/1M input and $15/1M output tokens. o3 Mini costs $1.1/1M input and $4.4/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude 3.5 Sonnet or o3 Mini open source?
Claude 3.5 Sonnet is listed under Unknown. o3 Mini 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 Mini?
Claude 3.5 Sonnet 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 3.5 Sonnet or o3 Mini?
Claude 3.5 Sonnet 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 3.5 Sonnet and o3 Mini?
Claude 3.5 Sonnet is available on GCP Vertex AI, AWS Bedrock, Anthropic, OpenRouter, and Microsoft Foundry. o3 Mini is available on OpenRouter, Azure OpenAI, and OpenAI API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.