LLM Reference

Claude Sonnet 4.5 vs Grok-3

Claude Sonnet 4.5 (2025) and Grok-3 (2025) are frontier-tier reasoning models from Anthropic and xAI. Claude Sonnet 4.5 ships a 200k-token context window, while Grok-3 ships a 131k-token context window. On MMLU PRO, Claude Sonnet 4.5 leads by 6.1 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Claude Sonnet 4.5 is safer overall; choose Grok-3 when vision-heavy evaluation matters.

Decision scorecard

Local evidence first
SignalClaude Sonnet 4.5Grok-3
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsreasoning-heavy apps, multimodal apps, and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window200k131k
Cheapest output$15/1M tokens$2.40/1M tokens
Provider routes8 tracked4 tracked
Shared benchmarksMMLU PRO leader3 shared

Decision tradeoffs

Choose Claude Sonnet 4.5 when...
  • Claude Sonnet 4.5 holds a shared-benchmark lead on MMLU PRO, ahead by 6.1 points.
  • Claude Sonnet 4.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Claude Sonnet 4.5 has broader tracked provider coverage for fallback and route flexibility.
  • Local decision data tags Claude Sonnet 4.5 for Coding, RAG, and Agents.
Choose Grok-3 when...
  • Grok-3 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 1.2 points.
  • 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.

Lower estimate Grok-3

Claude Sonnet 4.5

$6,150

Cheapest tracked route/tier: Microsoft Foundry

Grok-3

$1,240

Cheapest tracked route/tier: Chutes AI

Estimated monthly gap: $4,910. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Sonnet 4.5 -> Grok-3
  • Provider overlap exists on OpenRouter and Microsoft Foundry; start route-level A/B tests there.
  • Grok-3 is $12.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Grok-3 -> Claude Sonnet 4.5
  • Provider overlap exists on Microsoft Foundry and OpenRouter; start route-level A/B tests there.
  • Claude Sonnet 4.5 is $12.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.

Specs

Specification
Released2025-09-292025-02-17
Context window200k131k
Parameters——
ArchitectureDecoder Only-
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-122025-04

Pricing and availability

Pricing attributeClaude Sonnet 4.5Grok-3
Input price
0-200,001t
$3/1M tokens
200,001t+
$6/1M tokens
$0.80/1M tokens
Output price
0-200,001t
$15/1M tokens
200,001t+
$22.50/1M tokens
$2.40/1M tokens
Providers
Microsoft FoundryAnthropicSnowflake CortexGCP Vertex AIAWS BedrockReplicate API
OpenRouterxAI ConsoleChutes AIMicrosoft Foundry

Capabilities

CapabilityClaude Sonnet 4.5Grok-3
VisionYesYes
MultimodalYesYes
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionNoNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Sonnet 4.5Grok-3
MMLU PRO86.079.9
Google-Proof Q&A83.484.6
Massive Multi-discipline Multimodal Understanding77.878.0

Continue comparing

Model pages
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.