Claude Sonnet 4.5 vs Grok 4.3
Claude Sonnet 4.5 (2025) and Grok 4.3 (2026) are frontier-tier reasoning models from Anthropic and xAI. Claude Sonnet 4.5 ships a 200k-token context window, while Grok 4.3 ships a 1m-token context window. On Google-Proof Q&A, Grok 4.3 leads by 6.7 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Grok 4.3 fits 5x more tokens; pick it for long-context work and Claude Sonnet 4.5 for tighter calls.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 4.5 | Grok 4.3 |
|---|---|---|
| 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 | RAG, Agents, and Long context |
| Context window | 200k | 1m |
| Cheapest output | $15/1M tokens | $2.50/1M tokens |
| Provider routes | 8 tracked | 5 tracked |
| Shared benchmarks | 1 shared | Google-Proof Q&A leader |
Decision tradeoffs
- Claude Sonnet 4.5 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Claude Sonnet 4.5 for Coding, RAG, and Agents.
- Grok 4.3 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 6.7 points.
- Grok 4.3 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4.3 has the lower cheapest tracked output price at $2.50/1M tokens.
- Local decision data tags Grok 4.3 for RAG, Agents, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Sonnet 4.5
$6,150
Cheapest tracked route/tier: Microsoft Foundry
Grok 4.3
$1,625
Cheapest tracked route/tier: xAI Console
Estimated monthly gap: $4,525. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter, Microsoft Foundry, and Vercel AI Gateway; start route-level A/B tests there.
- Grok 4.3 is $12.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on Microsoft Foundry, AWS Bedrock, and OpenRouter; start route-level A/B tests there.
- Claude Sonnet 4.5 is $12.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-29 | 2026-05-06 |
| Context window | 200k | 1m |
| Parameters | — | ~0.5T |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-12 | 2024-11 |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.5 | Grok 4.3 |
|---|---|---|
| Input price |
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| Output price |
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| Providers |
Capabilities
| Capability | Claude Sonnet 4.5 | Grok 4.3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Sonnet 4.5 | Grok 4.3 |
|---|---|---|
| Google-Proof Q&A | 83.4 | 90.1 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Claude Sonnet 4.5 at 83.4 and Grok 4.3 at 90.1, with Grok 4.3 ahead by 6.7 points. The largest visible gap is 6.7 points on Google-Proof Q&A, 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 is close: both models cover vision, multimodal input, reasoning mode, function calling, and tool use. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Claude Sonnet 4.5 lists tiered pricing: 0-200,001t is $3/1M input and $15/1M output; 200,001t+ is $6/1M input and $22.50/1M output, while Grok 4.3 lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. A 70/30 input-output blend puts Grok 4.3 lower by about $4.97 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 8 providers versus 5, so concentration risk also matters.
Choose Claude Sonnet 4.5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose Grok 4.3 when long-context analysis, larger context windows, and lower cheapest-tier 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 Grok 4.3?
Grok 4.3 supports 1m 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 Grok 4.3?
Claude Sonnet 4.5 lists tiered pricing: 0-200,001t is $3/1M input and $15/1M output; 200,001t+ is $6/1M input and $22.50/1M output. Grok 4.3 lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Claude Sonnet 4.5 or Grok 4.3 open source?
Claude Sonnet 4.5 is listed under Proprietary. Grok 4.3 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 Sonnet 4.5 or Grok 4.3?
Both Claude Sonnet 4.5 and Grok 4.3 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 Sonnet 4.5 or Grok 4.3?
Both Claude Sonnet 4.5 and Grok 4.3 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 Grok 4.3?
Claude Sonnet 4.5 is available on Microsoft Foundry, Anthropic, Snowflake Cortex, GCP Vertex AI, and AWS Bedrock. Grok 4.3 is available on xAI Console, OpenRouter, Microsoft Foundry, Vercel AI Gateway, and AWS Bedrock. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-18. Data sourced from public model cards and provider documentation.