GPT-5.4 vs GPT-5.1 Codex Comparison

Comparing GPT-5.4 and GPT-5.1 Codex across benchmarks, pricing, and capabilities.

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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

GPT-5.4 outperforms in 1 benchmarks (Terminal-Bench 2.0), while GPT-5.1 Codex is better at 0 benchmarks.

GPT-5.4 significantly outperforms across most benchmarks.

Tue Mar 17 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.1 Codex costs less

For input processing, GPT-5.4 ($2.50/1M tokens) is 2.0x more expensive than GPT-5.1 Codex ($1.25/1M tokens).

For output processing, GPT-5.4 ($15.00/1M tokens) is 1.5x more expensive than GPT-5.1 Codex ($10.00/1M tokens).

In conclusion, GPT-5.4 is more expensive than GPT-5.1 Codex.*

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

Lowest available price from all providers
Tue Mar 17 2026 • llm-stats.com
OpenAI
GPT-5.4
Input tokens$2.50
Output tokens$15.00
Best providerOpenAI
OpenAI
GPT-5.1 Codex
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-5.4 accepts 1,000,000 input tokens compared to GPT-5.1 Codex's 400,000 tokens. Both models can generate responses up to 128,000 tokens.

OpenAI
GPT-5.4
Input1,000,000 tokens
Output128,000 tokens
OpenAI
GPT-5.1 Codex
Input400,000 tokens
Output128,000 tokens
Tue Mar 17 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.4 and GPT-5.1 Codex support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

GPT-5.4

Text
Images
Audio
Video

GPT-5.1 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-5.1 Codex

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.4 was released on 2026-03-05, while GPT-5.1 Codex was released on 2025-11-19.

GPT-5.4 is 4 months newer than GPT-5.1 Codex.

GPT-5.4

Mar 5, 2026

1 weeks ago

3mo newer
GPT-5.1 Codex

Nov 19, 2025

3 months ago

Knowledge Cutoff

When training data ends

GPT-5.1 Codex has a documented knowledge cutoff of 2024-09-30, while GPT-5.4's cutoff date is not specified.

We can confirm GPT-5.1 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-5.1 Codex

Sep 2024

Provider Availability

GPT-5.4 is available from OpenAI. GPT-5.1 Codex is available from OpenAI. The availability of providers can affect quality of the model and reliability.

GPT-5.4

openai logo
OpenAI
Input Price:Input: $2.50/1MOutput Price:Output: $15.00/1M

GPT-5.1 Codex

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

Outputs Comparison

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Key Takeaways

OpenAI
Larger context window (1,000,000 tokens)
Higher Terminal-Bench 2.0 score (75.1% vs 52.8%)
OpenAI
Less expensive input tokens
Less expensive output tokens

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT-5.4
OpenAI
GPT-5.1 Codex