Claude Opus 4.5 vs Phi-3 Mini 4k
Claude Opus 4.5 (2025) and Phi-3 Mini 4k (2024) are frontier reasoning models from Anthropic and Microsoft Research. Claude Opus 4.5 ships a 200k-token context window, while Phi-3 Mini 4k ships a 4k-token context window. On MMLU PRO, Claude Opus 4.5 leads by 43.2 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Phi-3 Mini 4k is ~9900% cheaper at $0.05/1M; pay for Claude Opus 4.5 only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Claude Opus 4.5 | Phi-3 Mini 4k |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding and Classification |
| Context window | 200k | 4k |
| Cheapest output | $25/1M tokens | $0.25/1M tokens |
| Provider routes | 6 tracked | 4 tracked |
| Shared benchmarks | MMLU PRO leader | 2 shared |
Decision tradeoffs
- Claude Opus 4.5 holds a shared-benchmark lead on MMLU PRO, ahead by 43.2 points.
- Claude Opus 4.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Claude Opus 4.5 has broader tracked provider coverage for fallback and route flexibility.
- Claude Opus 4.5 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Claude Opus 4.5 for Coding, RAG, and Agents.
- Phi-3 Mini 4k has the lower cheapest tracked output price at $0.25/1M tokens.
- Local decision data tags Phi-3 Mini 4k for Coding and Classification.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Opus 4.5
$10,250
Cheapest tracked route/tier: Microsoft Foundry
Phi-3 Mini 4k
$103
Cheapest tracked route/tier: Replicate API
Estimated monthly gap: $10,148. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Phi-3 Mini 4k is $24.75/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Claude Opus 4.5 is $24.75/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Opus 4.5 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-01 | 2024-04-23 |
| Context window | 200k | 4k |
| Parameters | — | 3.8B |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Weights | Not released | Unknown |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2025-12 | 2023-10 |
Pricing and availability
| Pricing attribute | Claude Opus 4.5 | Phi-3 Mini 4k |
|---|---|---|
| Input price | $5/1M tokens | $0.05/1M tokens |
| Output price | $25/1M tokens | $0.25/1M tokens |
| Providers |
Capabilities
| Capability | Claude Opus 4.5 | Phi-3 Mini 4k |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| JSON / Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Opus 4.5 | Phi-3 Mini 4k |
|---|---|---|
| MMLU PRO | 88.9 | 45.7 |
| Google-Proof Q&A | 87.0 | 40.9 |
Continue comparing
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.