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Claude Opus 4.5 vs Grok 4.3

How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Opus 4.5 and Grok 4.3.

Anthropic

Claude Opus 4.5

Claude Opus 4.5 is Anthropic’s frontier reasoning model optimized for complex software engineering, agentic workflows, and long-horizon computer use. It offers strong multimodal capabilities, competitive performance across real-world coding and...

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xAI

Grok 4.3

Grok 4.3 is a reasoning model from xAI. It accepts text and image inputs with text output, and is suited for agentic workflows, instruction-following tasks, and applications requiring high factual...

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Technical Specifications

SpecificationClaude Opus 4.5Grok 4.3
ProviderAnthropicxAI
Context Window200,000 tokens1,000,000 tokens
Agent Suitability93/10087/100
Time to First Token (TTFT)550 ms400 ms
Deployment Modelmanaged apimanaged api
Production Stabilitystablestable
API AvailableYesYes
Released Date2025-11-242026-04-30

API Pricing Comparison

Input Price per Million Tokens

Claude Opus 4.5

$5.00

Grok 4.3

$1.25

Output Price per Million Tokens

Claude Opus 4.5

$25.00

Grok 4.3

$2.50

Want to test both models live?

Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.

Benchmark Performance Metrics

Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.

MMLUGeneral knowledge & multi-task understanding
9280.0%vs9240.0%
Claude Opus 4.5
Grok 4.3
HumanEvalPython coding & logic synthesis
9420.0%vs9450.0%
Claude Opus 4.5
Grok 4.3
MATHComplex mathematical problem solving
8750.0%vs9100.0%
Claude Opus 4.5
Grok 4.3
GPQAGraduate-level expert reasoning
7600.0%vs8100.0%
Claude Opus 4.5
Grok 4.3
HellaSwagCommonsense reasoning and inference
9720.0%vs9750.0%
Claude Opus 4.5
Grok 4.3
MT-BenchMulti-turn conversation flow quality
955.0%vs940.0%
Claude Opus 4.5
Grok 4.3

Claude Opus 4.5 Quirks & Gotchas

  • Deep analytical reasoning — best for structured problem-solving
  • 200K context is limiting compared to 1M of Opus 4.6+ — upgrade for long-document tasks

Grok 4.3 Quirks & Gotchas

  • Strong coding performance — competitive with Claude Sonnet at similar price point
  • Upgrade to Grok 4.20 for improved reasoning and tool calling