Model Comparison

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

Both models are evenly matched across the benchmarks. GPT-5.1 High is 2.9x cheaper per token.

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

Claude Opus 4.5 (by Anthropic) and GPT-5.1 High (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 (LiveBench), while GPT-5.1 High is better at 1 benchmark (GPQA). Both models are evenly matched across the benchmarks.

On price, GPT-5.1 High 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 High 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 most recent training data — it shipped Nov 2025

Choose GPT-5.1 High if…

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

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Opus 4.5 outperforms in 1 benchmarks (LiveBench), while GPT-5.1 High is better at 1 benchmark (GPQA).

Both models are evenly matched across the benchmarks.

Mon Jun 29 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.1 High costs less

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

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

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

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

Lowest available price from all providers
Mon Jun 29 2026 • llm-stats.com
Anthropic
Claude Opus 4.5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
OpenAI
GPT-5.1 High
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 High accepts 400,000 input tokens compared to Claude Opus 4.5's 200,000 tokens. GPT-5.1 High 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 High
Input400,000 tokens
Output128,000 tokens
Mon Jun 29 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4.5 and GPT-5.1 High 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 High

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 High

Proprietary

Closed source

Release Timeline

When each model was launched

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

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

Claude Opus 4.5

Nov 24, 2025

7 months ago

1w newer
GPT-5.1 High

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 High'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 High's cutoff date.

Claude Opus 4.5

Mar 2025

GPT-5.1 High

—

Provider Availability

Claude Opus 4.5 is available from Anthropic. GPT-5.1 High 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 High

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 LiveBench score (76.0% vs 72.0%)
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

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Opus 4.5 and GPT-5.1 High side-by-side, then vote on the output you prefer.

Claude Opus 4.5
✓ Preferred
GPT-5.1 High
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Opus 4.5
OpenAI
GPT-5.1 High

FAQ

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

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

Both models are evenly matched across the benchmarks. Claude Opus 4.5 is made by Anthropic and GPT-5.1 High 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 High 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 High scores AIME 2025: 99.6%, GPQA: 88.1%, LiveBench: 72.0%.

Is Claude Opus 4.5 cheaper than GPT-5.1 High?

GPT-5.1 High 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 High 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 High?

Claude Opus 4.5 supports 200K tokens and GPT-5.1 High 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 High?

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 High?

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

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