Model Comparison

Claude Opus 4.5 vs o1-proWhich is better in 2026?

Claude Opus 4.5 significantly outperforms across most benchmarks.

Verdict: Claude Opus 4.5 vs o1-pro — which is better?

Claude Opus 4.5 (by Anthropic) and o1-pro (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Claude Opus 4.5 outperforms in 1 benchmarks (GPQA), while o1-pro is better at 0 benchmarks. Claude Opus 4.5 significantly outperforms across most benchmarks.

Choose Claude Opus 4.5 if…

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • you want the most recent training data — it shipped Nov 2025

Choose o1-pro if…

  • you are already invested in the OpenAI ecosystem
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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Claude Opus 4.5 outperforms in 1 benchmarks (GPQA), while o1-pro is better at 0 benchmarks.

Claude Opus 4.5 significantly outperforms across most benchmarks.

Sat Jun 06 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Claude Opus 4.5 specifies input context (200,000 tokens). Only Claude Opus 4.5 specifies output context (64,000 tokens).

Anthropic
Claude Opus 4.5
Input200,000 tokens
Output64,000 tokens
OpenAI
o1-pro
Input- tokens
Output- tokens
Sat Jun 06 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4.5 and o1-pro support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Opus 4.5

Text
Images
Audio
Video

o1-pro

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Opus 4.5

Proprietary

Closed source

o1-pro

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4.5 was released on 2025-11-24, while o1-pro was released on 2024-12-17.

Claude Opus 4.5 is 11 months newer than o1-pro.

Claude Opus 4.5

Nov 24, 2025

6 months ago

11mo newer
o1-pro

Dec 17, 2024

1.5 years ago

Knowledge Cutoff

When training data ends

Claude Opus 4.5 has a knowledge cutoff of 2025-03-31, while o1-pro has a cutoff of 2023-09-30.

Claude Opus 4.5 has more recent training data (up to 2025-03-31), making it potentially better informed about events through that date compared to o1-pro (2023-09-30).

Claude Opus 4.5

Mar 2025

1.5 yr newer
o1-pro

Sep 2023

Outputs Comparison

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Key Takeaways

Anthropic
Larger context window (200,000 tokens)
Higher GPQA score (87.0% vs 79.0%)
OpenAI

No standout differentiators in the data we have for this pair.

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Opus 4.5
OpenAI
o1-pro

FAQ

Common questions about Claude Opus 4.5 vs o1-pro.

Which is better, Claude Opus 4.5 or o1-pro?

Claude Opus 4.5 significantly outperforms across most benchmarks. Claude Opus 4.5 is made by Anthropic and o1-pro is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Opus 4.5 compare to o1-pro in benchmarks?

Claude Opus 4.5 scores Tau2 Telecom: 98.2%, MMMLU: 90.8%, Tau2 Retail: 88.9%, GPQA: 87.0%, SWE-Bench Verified: 80.9%. o1-pro scores AIME 2024: 86.0%, GPQA: 79.0%.

What are the context window sizes for Claude Opus 4.5 and o1-pro?

Claude Opus 4.5 supports 200K tokens and o1-pro supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

Who makes Claude Opus 4.5 and o1-pro?

Claude Opus 4.5 is developed by Anthropic and o1-pro is developed by OpenAI.

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