Model Comparison

Claude Opus 4.5 vs GPT-5.1 ThinkingWhich is better in 2026?

Claude Opus 4.5 shows notably better performance in the majority of benchmarks. GPT-5.1 Thinking is 2.9x cheaper per token.

Verdict: Claude Opus 4.5 vs GPT-5.1 Thinking — which is better?

Claude Opus 4.5 (by Anthropic) and GPT-5.1 Thinking (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 3 benchmarks (SWE-Bench Verified, Tau2 Retail, Tau2 Telecom), while GPT-5.1 Thinking is better at 1 benchmark (GPQA). Claude Opus 4.5 shows notably better performance in the majority of benchmarks.

On price, GPT-5.1 Thinking is roughly 2.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.1 Thinking also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Claude Opus 4.5 if…

  • you want the strongest raw capability — it leads on 3 of 4 shared benchmarks
  • you want the most recent training data — it shipped Nov 2025

Choose GPT-5.1 Thinking if…

  • cost matters — it's about 2.9x cheaper per token
  • you process long inputs — it offers a 400,000 token context window
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Performance Benchmarks

Comparative analysis across standard metrics

4 benchmarks

Claude Opus 4.5 outperforms in 3 benchmarks (SWE-Bench Verified, Tau2 Retail, Tau2 Telecom), while GPT-5.1 Thinking is better at 1 benchmark (GPQA).

Claude Opus 4.5 shows notably better performance in the majority of benchmarks.

Sat Jun 13 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.1 Thinking costs less

For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 4.0x more expensive than GPT-5.1 Thinking ($1.25/1M tokens).

For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 2.5x more expensive than GPT-5.1 Thinking ($10.00/1M tokens).

In conclusion, Claude Opus 4.5 is more expensive than GPT-5.1 Thinking.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Sat Jun 13 2026 • llm-stats.com
Anthropic
Claude Opus 4.5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
OpenAI
GPT-5.1 Thinking
Input tokens$1.25
Output tokens$10.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.1 Thinking accepts 400,000 input tokens compared to Claude Opus 4.5's 200,000 tokens. GPT-5.1 Thinking can generate longer responses up to 128,000 tokens, while Claude Opus 4.5 is limited to 64,000 tokens.

Anthropic
Claude Opus 4.5
Input200,000 tokens
Output64,000 tokens
OpenAI
GPT-5.1 Thinking
Input400,000 tokens
Output128,000 tokens
Sat Jun 13 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4.5 and GPT-5.1 Thinking 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

GPT-5.1 Thinking

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

GPT-5.1 Thinking

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4.5 was released on 2025-11-24, while GPT-5.1 Thinking was released on 2025-11-12.

Claude Opus 4.5 is 0 month newer than GPT-5.1 Thinking.

Claude Opus 4.5

Nov 24, 2025

6 months ago

1w newer
GPT-5.1 Thinking

Nov 12, 2025

7 months ago

Knowledge Cutoff

When training data ends

Claude Opus 4.5 has a documented knowledge cutoff of 2025-03-31, while GPT-5.1 Thinking's cutoff date is not specified.

We can confirm Claude Opus 4.5's training data extends to 2025-03-31, but cannot make a direct comparison without GPT-5.1 Thinking's cutoff date.

Claude Opus 4.5

Mar 2025

GPT-5.1 Thinking

—

Provider Availability

Claude Opus 4.5 is available from Anthropic. GPT-5.1 Thinking is available from OpenAI.

Claude Opus 4.5

anthropic logo
Anthropic
Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M

GPT-5.1 Thinking

openai logo
OpenAI
Input Price:Input: $1.25/1MOutput Price:Output: $10.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Higher SWE-Bench Verified score (80.9% vs 76.3%)
Higher Tau2 Retail score (88.9% vs 77.9%)
Higher Tau2 Telecom score (98.2% vs 95.6%)
OpenAI
Larger context window (400,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher GPQA score (88.1% vs 87.0%)

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Opus 4.5
OpenAI
GPT-5.1 Thinking

FAQ

Common questions about Claude Opus 4.5 vs GPT-5.1 Thinking.

Which is better, Claude Opus 4.5 or GPT-5.1 Thinking?

Claude Opus 4.5 shows notably better performance in the majority of benchmarks. Claude Opus 4.5 is made by Anthropic and GPT-5.1 Thinking 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 GPT-5.1 Thinking 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%. GPT-5.1 Thinking scores Tau2 Telecom: 95.6%, AIME 2025: 94.0%, BrowseComp Long Context 128k: 90.0%, GPQA: 88.1%, MMMU: 85.4%.

Is Claude Opus 4.5 cheaper than GPT-5.1 Thinking?

GPT-5.1 Thinking is 4.0x cheaper for input tokens. Claude Opus 4.5 costs $5.00/M input and $25.00/M output via anthropic. GPT-5.1 Thinking costs $1.25/M input and $10.00/M output via openai.

What are the context window sizes for Claude Opus 4.5 and GPT-5.1 Thinking?

Claude Opus 4.5 supports 200K tokens and GPT-5.1 Thinking supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 4.5 and GPT-5.1 Thinking?

Key differences include context window (200K vs 400K), input pricing ($5.00 vs $1.25/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 4.5 and GPT-5.1 Thinking?

Claude Opus 4.5 is developed by Anthropic and GPT-5.1 Thinking is developed by OpenAI.

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