Claude Opus 4.5 vs Grok-3
Claude Opus 4.5 (2025) and Grok-3 (2025) are frontier-tier reasoning models from Anthropic and xAI. Claude Opus 4.5 ships a 200k-token context window, while Grok-3 ships a 131k-token context window. On MMLU PRO, Claude Opus 4.5 leads by 9 pts. On pricing, Grok-3 costs $0.80/1M input tokens versus $5/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Grok-3 is ~525% cheaper at $0.80/1M; pay for Claude Opus 4.5 only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Claude Opus 4.5 | Grok-3 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 200k | 131k |
| Cheapest output | $25/1M tokens | $2.40/1M tokens |
| Provider routes | 6 tracked | 4 tracked |
| Shared benchmarks | MMLU PRO leader | 5 shared |
Decision tradeoffs
- Claude Opus 4.5 holds a shared-benchmark lead on MMLU PRO, ahead by 9 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 Code execution in local model data.
- Local decision data tags Claude Opus 4.5 for Coding, RAG, and Agents.
- Grok-3 has the lower cheapest tracked output price at $2.40/1M tokens.
- Local decision data tags Grok-3 for Coding, RAG, and Agents.
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
Grok-3
$1,240
Cheapest tracked route/tier: Chutes AI
Estimated monthly gap: $9,010. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and Microsoft Foundry; start route-level A/B tests there.
- Grok-3 is $22.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Code execution before moving production traffic.
- Provider overlap exists on Microsoft Foundry and OpenRouter; start route-level A/B tests there.
- Claude Opus 4.5 is $22.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Opus 4.5 adds Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-01 | 2025-02-17 |
| Context window | 200k | 131k |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-12 | 2025-04 |
Pricing and availability
| Pricing attribute | Claude Opus 4.5 | Grok-3 |
|---|---|---|
| Input price | $5/1M tokens | $0.80/1M tokens |
| Output price | $25/1M tokens | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | Claude Opus 4.5 | Grok-3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Opus 4.5 | Grok-3 |
|---|---|---|
| MMLU PRO | 88.9 | 79.9 |
| Google-Proof Q&A | 87.0 | 84.6 |
| Massive Multi-discipline Multimodal Understanding | 80.7 | 78.0 |
| Chatbot Arena | 1466.0 | 1405.0 |
| Aider Polyglot | 72.0 | 53.3 |
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.