Model Comparison

GPT-5.4 vs GPT-5 CodexWhich is better in 2026?

Comparing GPT-5.4 and GPT-5 Codex across benchmarks, pricing, and capabilities.

Verdict: GPT-5.4 vs GPT-5 Codex — which is better?

GPT-5.4 (by OpenAI) and GPT-5 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.

Choose GPT-5.4 if…

  • you want the most recent training data — it shipped Mar 2026

Choose GPT-5 Codex if…

  • you are already invested in the OpenAI ecosystem
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Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

GPT-5.4 and GPT-5 Codex don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-5.4 specifies input context (1,000,000 tokens). Only GPT-5.4 specifies output context (128,000 tokens).

OpenAI
GPT-5.4
Input1,000,000 tokens
Output128,000 tokens
OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
Mon Jun 08 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-5.4 supports multimodal inputs, whereas GPT-5 Codex does not.

GPT-5.4 can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5.4

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.

GPT-5.4

Proprietary

Closed source

GPT-5 Codex

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.4 was released on 2026-03-05, while GPT-5 Codex was released on 2025-09-15.

GPT-5.4 is 6 months newer than GPT-5 Codex.

GPT-5.4

Mar 5, 2026

3 months ago

5mo newer
GPT-5 Codex

Sep 15, 2025

8 months ago

Knowledge Cutoff

When training data ends

GPT-5 Codex has a documented knowledge cutoff of 2024-09-30, while GPT-5.4'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 GPT-5.4's cutoff date.

GPT-5.4

—

GPT-5 Codex

Sep 2024

Outputs Comparison

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Key Takeaways

OpenAI
Larger context window (1,000,000 tokens)
Supports multimodal inputs
OpenAI

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

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT-5.4
OpenAI
GPT-5 Codex

FAQ

Common questions about GPT-5.4 vs GPT-5 Codex.

Which is better, GPT-5.4 or GPT-5 Codex?

GPT-5.4 (OpenAI) and GPT-5 Codex (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does GPT-5.4 compare to GPT-5 Codex in benchmarks?

GPT-5.4 scores Tau2 Telecom: 98.9%, ARC-AGI: 93.7%, Graphwalks BFS <128k: 93.0%, GPQA: 92.8%, Graphwalks parents <128k: 89.8%. GPT-5 Codex scores SWE-Bench Verified: 74.5%.

What are the context window sizes for GPT-5.4 and GPT-5 Codex?

GPT-5.4 supports 1.0M 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 GPT-5.4 and GPT-5 Codex?

Key differences include multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

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