Claude Sonnet 4.5 vs o4-mini
Claude Sonnet 4.5 (2025) and o4-mini (2025) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Sonnet 4.5 ships a 200K-token context window, while o4-mini ships a not-yet-sourced context window. On MMLU PRO, Claude Sonnet 4.5 leads by 2.8 pts. On pricing, o4-mini costs $0.5/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
o4-mini is ~500% cheaper at $0.5/1M; pay for Claude Sonnet 4.5 only for vision-heavy evaluation.
Specs
| Released | 2025-09-29 | 2025-04-16 |
| Context window | 200K | — |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | 2025-08 |
Pricing and availability
| Claude Sonnet 4.5 | o4-mini | |
|---|---|---|
| Input price | $3/1M tokens | $0.5/1M tokens |
| Output price | $15/1M tokens | $2/1M tokens |
| Providers |
Capabilities
| Claude Sonnet 4.5 | o4-mini | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | Claude Sonnet 4.5 | o4-mini |
|---|---|---|
| MMLU PRO | 86.0 | 83.2 |
| BFCL | 73.2 | 53.2 |
| Massive Multi-discipline Multimodal Understanding | 77.8 | 81.6 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude Sonnet 4.5 at 86 and o4-mini at 83.2, with Claude Sonnet 4.5 ahead by 2.8 points; BFCL has Claude Sonnet 4.5 at 73.2 and o4-mini at 53.2, with Claude Sonnet 4.5 ahead by 20.0 points; Massive Multi-discipline Multimodal Understanding has Claude Sonnet 4.5 at 77.8 and o4-mini at 81.6, with o4-mini ahead by 3.8 points. The largest visible gap is 20.0 points on BFCL, 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: o4-mini. 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.
For cost, Claude Sonnet 4.5 lists $3/1M input and $15/1M output tokens, while o4-mini lists $0.5/1M input and $2/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts o4-mini lower by about $5.65 per million blended tokens. Availability is 8 providers versus 4, so concentration risk also matters.
Choose Claude Sonnet 4.5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose o4-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 is cheaper, Claude Sonnet 4.5 or o4-mini?
o4-mini is cheaper on tracked token pricing. Claude Sonnet 4.5 costs $3/1M input and $15/1M output tokens. o4-mini costs $0.5/1M input and $2/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Sonnet 4.5 or o4-mini open source?
Claude Sonnet 4.5 is listed under Proprietary. o4-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 Sonnet 4.5 or o4-mini?
Both Claude Sonnet 4.5 and o4-mini 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 4.5 or o4-mini?
Both Claude Sonnet 4.5 and o4-mini expose multimodal input. 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 reasoning mode, Claude Sonnet 4.5 or o4-mini?
Both Claude Sonnet 4.5 and o4-mini expose reasoning mode. 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.
Where can I run Claude Sonnet 4.5 and o4-mini?
Claude Sonnet 4.5 is available on Microsoft Foundry, Anthropic, Snowflake Cortex, GCP Vertex AI, and AWS Bedrock. o4-mini is available on OpenAI API, OpenRouter, OpenAI Batch API, and Replicate API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.