Model Comparison
Claude Opus 4.5 vs GPT-5.2 CodexWhich is better in 2026?
GPT-5.2 Codex significantly outperforms across most benchmarks. GPT-5.2 Codex is 2.1x cheaper per token.
Verdict: Claude Opus 4.5 vs GPT-5.2 Codex — which is better?
Claude Opus 4.5 (by Anthropic) and GPT-5.2 Codex (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 0 benchmarks, while GPT-5.2 Codex is better at 1 benchmark (Terminal-Bench 2.0). GPT-5.2 Codex significantly outperforms across most benchmarks.
On price, GPT-5.2 Codex is roughly 2.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.2 Codex 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 predictable pricing at $5.00/M input and $25.00/M output
Choose GPT-5.2 Codex if…
- you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
- cost matters — it's about 2.1x cheaper per token
- you process long inputs — it offers a 400,000 token context window
- you want the most recent training data — it shipped Jan 2026
Performance Benchmarks
Comparative analysis across standard metrics
Claude Opus 4.5 outperforms in 0 benchmarks, while GPT-5.2 Codex is better at 1 benchmark (Terminal-Bench 2.0).
GPT-5.2 Codex significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 2.9x more expensive than GPT-5.2 Codex ($1.75/1M tokens).
For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 1.8x more expensive than GPT-5.2 Codex ($14.00/1M tokens).
In conclusion, Claude Opus 4.5 is more expensive than GPT-5.2 Codex.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.2 Codex accepts 400,000 input tokens compared to Claude Opus 4.5's 200,000 tokens. GPT-5.2 Codex can generate longer responses up to 128,000 tokens, while Claude Opus 4.5 is limited to 64,000 tokens.
Input Capabilities
Supported data types and modalities
Both Claude Opus 4.5 and GPT-5.2 Codex support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Opus 4.5
GPT-5.2 Codex
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Opus 4.5 was released on 2025-11-24, while GPT-5.2 Codex was released on 2026-01-14.
GPT-5.2 Codex is 2 months newer than Claude Opus 4.5.
Nov 24, 2025
6 months ago
Jan 14, 2026
5 months ago
1mo newerKnowledge Cutoff
When training data ends
Claude Opus 4.5 has a documented knowledge cutoff of 2025-03-31, while GPT-5.2 Codex'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-5.2 Codex's cutoff date.
Mar 2025
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Provider Availability
Claude Opus 4.5 is available from Anthropic. GPT-5.2 Codex is available from OpenAI.
Claude Opus 4.5
GPT-5.2 Codex
Outputs Comparison
Key Takeaways
Claude Opus 4.5
View detailsAnthropic
No standout differentiators in the data we have for this pair.
Detailed Comparison
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FAQ
Common questions about Claude Opus 4.5 vs GPT-5.2 Codex.