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 rows |
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 procurement 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 |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| 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 |
| Function calling | Yes | Yes |
| 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 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude Opus 4.5 at 88.9 and Grok-3 at 79.9, with Claude Opus 4.5 ahead by 9 points; Google-Proof Q&A has Claude Opus 4.5 at 87 and Grok-3 at 84.6, with Claude Opus 4.5 ahead by 2.4 points; Massive Multi-discipline Multimodal Understanding has Claude Opus 4.5 at 80.7 and Grok-3 at 78, with Claude Opus 4.5 ahead by 2.7 points. The largest visible gap is 9 points on MMLU PRO, 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 on the cheapest tracked provider, while Grok-3 lists $0.80/1M input and $2.40/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok-3 lower by about $9.72 per million blended tokens. Availability is 6 providers versus 4, so concentration risk also matters.
Choose Claude Opus 4.5 when coding workflow support, larger context windows, and broader provider choice are central to the workload. Choose Grok-3 when vision-heavy evaluation 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 Opus 4.5 or Grok-3?
Claude Opus 4.5 supports 200k tokens, while Grok-3 supports 131k 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 Grok-3?
Grok-3 is cheaper on tracked token pricing. Claude Opus 4.5 costs $5/1M input and $25/1M output tokens. Grok-3 costs $0.80/1M input and $2.40/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 4.5 or Grok-3 open source?
Claude Opus 4.5 is listed under Proprietary. Grok-3 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 Grok-3?
Both Claude Opus 4.5 and Grok-3 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 Opus 4.5 or Grok-3?
Both Claude Opus 4.5 and Grok-3 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.
Where can I run Claude Opus 4.5 and Grok-3?
Claude Opus 4.5 is available on Microsoft Foundry, Anthropic, GCP Vertex AI, AWS Bedrock, and OpenRouter. Grok-3 is available on OpenRouter, xAI Console, Chutes AI, and Microsoft Foundry. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.