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GPT-5 Codex vs Grok-4

Comparing GPT-5 Codex and Grok-4 across benchmarks, pricing, and capabilities.

OpenAI · xAI · Updated for 2026

Which is better?

GPT-5 Codex and Grok-4 trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.

Based on current benchmark, pricing, and model metadata for 2026.

Choose GPT-5 Codex

  • you want the most recent training data — it shipped Sep 2025

Choose Grok-4

  • you want predictable pricing at $3.00/M input and $15.00/M output

At a glance

The differences that matter most.

GPT-5 Codex
OpenAI
Grok-4
xAI
Benchmark wins
—
—
Input price
— / M
$3.00 / M
Output price
— / M
$15.00 / M
Context window
—
256,000
Released
Sep 2025
Jul 2025
License
Proprietary
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

GPT-5 Codex and Grok-4don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only Grok-4 specifies input context (256,000 tokens). Only Grok-4 specifies output context (8,000 tokens).

OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
xAI
Grok-4
Input256,000 tokens
Output8,000 tokens
Tue Aug 25 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Grok-4 supports multimodal inputs, whereas GPT-5 Codex does not.

Grok-4 can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5 Codex

Text
Images
Audio
Video

Grok-4

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 Codex

Proprietary

Closed source

Grok-4

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5 Codex was released on 2025-09-15, while Grok-4 was released on 2025-07-09.

GPT-5 Codex is 2 months newer than Grok-4.

GPT-5 Codex

Sep 15, 2025

11 months ago

2mo newer
Grok-4

Jul 9, 2025

1.1 years ago

Knowledge Cutoff

When training data ends

GPT-5 Codex has a knowledge cutoff of 2024-09-30, while Grok-4 has a cutoff of 2024-12-31.

Grok-4 has more recent training data (up to 2024-12-31), making it potentially better informed about events through that date compared to GPT-5 Codex (2024-09-30).

GPT-5 Codex

Sep 2024

Grok-4

Dec 2024

3 mo newer

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against GPT-5 Codex and Grok-4 side-by-side, then vote on the output you prefer.

GPT-5 Codex
✓ Preferred
Grok-4
Open in Playground

FAQ

Common questions about GPT-5 Codex vs Grok-4.

Which is better, GPT-5 Codex or Grok-4?

GPT-5 Codex (OpenAI) and Grok-4 (xAI) 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 Codex compare to Grok-4 in benchmarks?

GPT-5 Codex scores SWE-Bench Verified: 74.5%. Grok-4 scores AIME 2025: 91.7%, HMMT25: 90.0%, GPQA: 87.5%, LiveCodeBench: 79.0%, Humanity's Last Exam: 40.0%.

What are the context window sizes for GPT-5 Codex and Grok-4?

GPT-5 Codex supports an unknown number of tokens and Grok-4 supports 256K 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 Codex and Grok-4?

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

Who makes GPT-5 Codex and Grok-4?

GPT-5 Codex is developed by OpenAI and Grok-4 is developed by xAI.

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