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Claude Opus 4.1 vs GPT-5 Codex

Claude Opus 4.1 and GPT-5 Codex are closely matched at 29.8 and 26.6 on the LLM Stats Score.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Opus 4.1 and GPT-5 Codex are closely matched on the overall LLM Stats Score at 29.8 and 26.6.

In the 1 individual benchmarks reported for both models, GPT-5 Codex wins 1; this is a narrower head-to-head signal than the composite indexes.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Opus 4.1

  • you want predictable pricing at $15.00/M input and $75.00/M output

Choose GPT-5 Codex

  • you value its reported benchmark strengths — it wins 1 of 1 exact shared results
  • you want the most recent training data — it shipped Sep 2025

At a glance

The differences that matter most.

Claude Opus 4.1
Anthropic
GPT-5 Codex
OpenAI
Core performance indexes
LLM Stats Score
29.8
#138
26.6
#165
Reasoning
29.9
#134
26.4
#163
Coding
21.3
#99
19.1
#119
Cost, coverage & limits
Benchmark wins
0 of 1
1 of 1
Input price
$15.00 / M
— / M
Output price
$75.00 / M
— / M
Context window
200,000
—

Individual benchmarks

8 reported for Claude Opus 4.1 · 1 for GPT-5 Codex

1 shared

Claude Opus 4.1 outperforms in 0 benchmarks, while GPT-5 Codex is better at 0 benchmarks.

Both models are evenly matched across the benchmarks.

Fri Oct 16 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Claude Opus 4.1 specifies input context (200,000 tokens). Only Claude Opus 4.1 specifies output context (32,000 tokens).

Anthropic
Claude Opus 4.1
Input200,000 tokens
Output32,000 tokens
OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
Fri Oct 16 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Opus 4.1 supports multimodal inputs, whereas GPT-5 Codex does not.

Claude Opus 4.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 4.1

Text
Images
Audio
Video

GPT-5 Codex

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 4.1

Proprietary

Closed source

GPT-5 Codex

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4.1 was released on 2025-08-05, while GPT-5 Codex was released on 2025-09-15.

GPT-5 Codex is 1 month newer than Claude Opus 4.1.

Claude Opus 4.1

Aug 5, 2025

1.2 years ago

GPT-5 Codex

Sep 15, 2025

1.1 years ago

1mo newer

Knowledge Cutoff

When training data ends

GPT-5 Codex has a documented knowledge cutoff of 2024-09-30, while Claude Opus 4.1's cutoff date is not specified.

We can confirm GPT-5 Codex's training data extends to 2024-09-30, but cannot make a direct comparison without Claude Opus 4.1's cutoff date.

Claude Opus 4.1

—

GPT-5 Codex

Sep 2024

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Opus 4.1 and GPT-5 Codex side-by-side, then vote on the output you prefer.

Claude Opus 4.1
✓ Preferred
GPT-5 Codex
Open in Playground

FAQ

Common questions about Claude Opus 4.1 vs GPT-5 Codex.

Which is better, Claude Opus 4.1 or GPT-5 Codex?

Claude Opus 4.1 and GPT-5 Codex are closely matched on the LLM Stats Score at 29.8 and 26.6. Claude Opus 4.1 is made by Anthropic and GPT-5 Codex is made by OpenAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Opus 4.1 compare to GPT-5 Codex in benchmarks?

Claude Opus 4.1 scores MMMLU: 89.5%, TAU-bench Retail: 82.4%, GPQA: 80.9%, AIME 2025: 78.0%, MMMU (validation): 77.1%. GPT-5 Codex scores SWE-Bench Verified: 74.5%.

What are the context window sizes for Claude Opus 4.1 and GPT-5 Codex?

Claude Opus 4.1 supports 200K tokens and GPT-5 Codex supports an unknown number of 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 4.1 and GPT-5 Codex?

Key differences include LLM Stats Score (29.8 vs 26.6), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 4.1 and GPT-5 Codex?

Claude Opus 4.1 is developed by Anthropic and GPT-5 Codex is developed by OpenAI.

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