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Claude Opus 4.5 vs o3 Pro

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 o3 Pro.

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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OpenAI

o3 Pro

The o-series of models are trained with reinforcement learning to think before they answer and perform complex reasoning. The o3-pro model uses more compute to think harder and provide consistently...

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Technical Specifications

SpecificationClaude Opus 4.5o3 Pro
ProviderAnthropicOpenAI
Context Window200,000 tokens200,000 tokens
Agent Suitability93/100N/A
Time to First Token (TTFT)550 msN/A
Deployment Modelmanaged apimanaged api
Production Stabilitystablestable
API AvailableYesYes
Released Date2025-11-242025-06-10

API Pricing Comparison

Input Price per Million Tokens

Claude Opus 4.5

$5.00

o3 Pro

$20.00

Output Price per Million Tokens

Claude Opus 4.5

$25.00

o3 Pro

$80.00

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%vsN/A
Claude Opus 4.5
o3 Pro
HumanEvalPython coding & logic synthesis
9420.0%vsN/A
Claude Opus 4.5
o3 Pro
MATHComplex mathematical problem solving
8750.0%vsN/A
Claude Opus 4.5
o3 Pro
GPQAGraduate-level expert reasoning
7600.0%vsN/A
Claude Opus 4.5
o3 Pro
HellaSwagCommonsense reasoning and inference
9720.0%vsN/A
Claude Opus 4.5
o3 Pro
MT-BenchMulti-turn conversation flow quality
955.0%vsN/A
Claude Opus 4.5
o3 Pro

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

o3 Pro Quirks & Gotchas

No developer gotchas reported.