Claude Sonnet 4.5 vs GPT-5 Mini
Claude Sonnet 4.5 (2025) and GPT-5 Mini (2025) are frontier-tier reasoning models from Anthropic and OpenAI. Claude Sonnet 4.5 ships a 200K-token context window, while GPT-5 Mini ships a 400K-token context window. On BFCL, Claude Sonnet 4.5 leads by 17.8 pts. On pricing, GPT-5 Mini costs $0.25/1M input tokens versus $3/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
GPT-5 Mini is ~1100% cheaper at $0.25/1M; pay for Claude Sonnet 4.5 only for vision-heavy evaluation.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 4.5 | GPT-5 Mini |
|---|---|---|
| Decision fit | RAG, Agents, and Long context | Coding, RAG, and Agents |
| Context window | 200K | 400K |
| Cheapest output | $15/1M tokens | $2/1M tokens |
| Provider routes | 7 tracked | 3 tracked |
| Shared benchmarks | BFCL leader | 1 rows |
Decision tradeoffs
- Claude Sonnet 4.5 leads the largest shared benchmark signal on BFCL by 17.8 points.
- Claude Sonnet 4.5 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Claude Sonnet 4.5 for RAG, Agents, and Long context.
- GPT-5 Mini has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5 Mini has the lower cheapest tracked output price at $2/1M tokens.
- GPT-5 Mini uniquely exposes Code execution in local model data.
- Local decision data tags GPT-5 Mini for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Claude Sonnet 4.5
$6,150
Cheapest tracked route: Microsoft Foundry
GPT-5 Mini
$700
Cheapest tracked route: Replicate API
Estimated monthly gap: $5,450. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Replicate API and OpenRouter; start route-level A/B tests there.
- GPT-5 Mini is $13/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- GPT-5 Mini adds Code execution in local capability data.
- Provider overlap exists on Replicate API and OpenRouter; start route-level A/B tests there.
- Claude Sonnet 4.5 is $13/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Code execution before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-29 | 2025-08-07 |
| Context window | 200K | 400K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | 2024-05 |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.5 | GPT-5 Mini |
|---|---|---|
| Input price | $3/1M tokens | $0.25/1M tokens |
| Output price | $15/1M tokens | $2/1M tokens |
| Providers |
Capabilities
| Capability | Claude Sonnet 4.5 | GPT-5 Mini |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
Benchmarks
| Benchmark | Claude Sonnet 4.5 | GPT-5 Mini |
|---|---|---|
| BFCL | 73.2 | 55.5 |
Deep dive
On shared benchmark coverage, BFCL has Claude Sonnet 4.5 at 73.2 and GPT-5 Mini at 55.5, with Claude Sonnet 4.5 ahead by 17.8 points. The largest visible gap is 17.8 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: GPT-5 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 GPT-5 Mini lists $0.25/1M input and $2/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-5 Mini lower by about $5.82 per million blended tokens. Availability is 7 providers versus 3, so concentration risk also matters.
Choose Claude Sonnet 4.5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose GPT-5 Mini when coding workflow support, larger context windows, 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 4.5 or GPT-5 Mini?
GPT-5 Mini supports 400K 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 Sonnet 4.5 or GPT-5 Mini?
GPT-5 Mini is cheaper on tracked token pricing. Claude Sonnet 4.5 costs $3/1M input and $15/1M output tokens. GPT-5 Mini costs $0.25/1M input and $2/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Sonnet 4.5 or GPT-5 Mini open source?
Claude Sonnet 4.5 is listed under Proprietary. GPT-5 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 GPT-5 Mini?
Both Claude Sonnet 4.5 and GPT-5 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 GPT-5 Mini?
Both Claude Sonnet 4.5 and GPT-5 Mini 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 Sonnet 4.5 and GPT-5 Mini?
Claude Sonnet 4.5 is available on Microsoft Foundry, Anthropic, Snowflake Cortex, GCP Vertex AI, and AWS Bedrock. GPT-5 Mini is available on Replicate API, OpenRouter, and OpenAI API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-19. Data sourced from public model cards and provider documentation.