Claude Opus 4.5 vs Claude Sonnet 4.5
Claude Opus 4.5 (2025) and Claude Sonnet 4.5 (2025) are frontier-tier reasoning models from Anthropic. Claude Opus 4.5 ships a 200K-token context window, while Claude Sonnet 4.5 ships a 200K-token context window. On MMLU PRO, Claude Opus 4.5 leads by 2.9 pts. On pricing, Claude Sonnet 4.5 costs $3/1M input tokens versus $5/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Claude Sonnet 4.5 is ~67% cheaper at $3/1M; pay for Claude Opus 4.5 only for coding workflow support.
Specs
| Released | 2025-11-01 | 2025-09-29 |
| Context window | 200K | 200K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | 2025-12 |
Pricing and availability
| Claude Opus 4.5 | Claude Sonnet 4.5 | |
|---|---|---|
| Input price | $5/1M tokens | $3/1M tokens |
| Output price | $25/1M tokens | $15/1M tokens |
| Providers |
Capabilities
| Claude Opus 4.5 | Claude Sonnet 4.5 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
| Benchmark | Claude Opus 4.5 | Claude Sonnet 4.5 |
|---|---|---|
| MMLU PRO | 88.9 | 86.0 |
| BFCL | 77.5 | 73.2 |
| Massive Multi-discipline Multimodal Understanding | 80.7 | 77.8 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude Opus 4.5 at 88.9 and Claude Sonnet 4.5 at 86, with Claude Opus 4.5 ahead by 2.9 points; BFCL has Claude Opus 4.5 at 77.5 and Claude Sonnet 4.5 at 73.2, with Claude Opus 4.5 ahead by 4.2 points; Massive Multi-discipline Multimodal Understanding has Claude Opus 4.5 at 80.7 and Claude Sonnet 4.5 at 77.8, with Claude Opus 4.5 ahead by 2.9 points. The largest visible gap is 4.2 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: Claude Opus 4.5. 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 Opus 4.5 lists $5/1M input and $25/1M output tokens, while Claude Sonnet 4.5 lists $3/1M input and $15/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Claude Sonnet 4.5 lower by about $4.4 per million blended tokens. Availability is 6 providers versus 8, so concentration risk also matters.
Choose Claude Opus 4.5 when coding workflow support are central to the workload. Choose Claude Sonnet 4.5 when vision-heavy evaluation, lower input-token cost, and broader provider choice 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 Opus 4.5 or Claude Sonnet 4.5?
Claude Opus 4.5 supports 200K tokens, while Claude Sonnet 4.5 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 Opus 4.5 or Claude Sonnet 4.5?
Claude Sonnet 4.5 is cheaper on tracked token pricing. Claude Opus 4.5 costs $5/1M input and $25/1M output tokens. Claude Sonnet 4.5 costs $3/1M input and $15/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 4.5 or Claude Sonnet 4.5 open source?
Claude Opus 4.5 is listed under Proprietary. Claude Sonnet 4.5 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 Opus 4.5 or Claude Sonnet 4.5?
Both Claude Opus 4.5 and Claude Sonnet 4.5 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 Opus 4.5 or Claude Sonnet 4.5?
Both Claude Opus 4.5 and Claude Sonnet 4.5 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 Opus 4.5 and Claude Sonnet 4.5?
Claude Opus 4.5 is available on Microsoft Foundry, Anthropic, GCP Vertex AI, AWS Bedrock, and OpenRouter. Claude Sonnet 4.5 is available on Microsoft Foundry, Anthropic, Snowflake Cortex, GCP Vertex AI, and AWS Bedrock. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.