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GPT-5 Codex vs GPT-6 Luna

GPT-6 Luna leads the LLM Stats Score 44.5 to 26.6.

OpenAI · OpenAI · Updated for 2026

Which is better?

GPT-6 Luna leads the overall LLM Stats Score 44.5 to 26.6, ranking #41 overall.

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

Choose GPT-5 Codex

  • you are already invested in the OpenAI ecosystem

Choose GPT-6 Luna

  • overall performance matters — it scores 44.5 and ranks #41 on LLM Stats
  • you want the most recent training data — it shipped Sep 2026

At a glance

The differences that matter most.

GPT-5 Codex
OpenAI
GPT-6 Luna
OpenAI
Core performance indexes
LLM Stats Score
26.6
#155
44.5
#41
Reasoning
26.5
#152
40.0
#58
Coding
19.3
#112
31.4
#47
Cost, coverage & limits
Benchmark wins
—
—
Input price
— / M
$0.10 / M
Output price
— / M
$0.50 / M
Context window
—
1,050,000

Individual benchmarks

1 reported for GPT-5 Codex · 5 for GPT-6 Luna

No common benchmarks found

GPT-5 Codex and GPT-6 Lunadon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only GPT-6 Luna specifies input context (1,050,000 tokens). Only GPT-6 Luna specifies output context (128,000 tokens).

OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
OpenAI
GPT-6 Luna
Input1,050,000 tokens
Output128,000 tokens
Tue Sep 22 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

GPT-6 Luna supports multimodal inputs, whereas GPT-5 Codex does not.

GPT-6 Luna can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5 Codex

Text
Images
Audio
Video

GPT-6 Luna

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

GPT-6 Luna

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5 Codex was released on 2025-09-15, while GPT-6 Luna was released on 2026-09-22.

GPT-6 Luna is 12 months newer than GPT-5 Codex.

GPT-5 Codex

Sep 15, 2025

1.0 years ago

GPT-6 Luna

Sep 22, 2026

0 days ago

1.0yr newer

Knowledge Cutoff

When training data ends

GPT-5 Codex has a knowledge cutoff of 2024-09-30, while GPT-6 Luna has a cutoff of 2026-05-18.

GPT-6 Luna has more recent training data (up to 2026-05-18), making it potentially better informed about events through that date compared to GPT-5 Codex (2024-09-30).

GPT-5 Codex

Sep 2024

GPT-6 Luna

May 2026

1.7 yr newer

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against GPT-5 Codex and GPT-6 Luna side-by-side, then vote on the output you prefer.

GPT-5 Codex
✓ Preferred
GPT-6 Luna
Open in Playground

FAQ

Common questions about GPT-5 Codex vs GPT-6 Luna.

Which is better, GPT-5 Codex or GPT-6 Luna?

GPT-6 Luna leads the LLM Stats Score 44.5 to 26.6. GPT-5 Codex is made by OpenAI and GPT-6 Luna is made by OpenAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5 Codex compare to GPT-6 Luna in benchmarks?

GPT-5 Codex scores SWE-Bench Verified: 74.5%. GPT-6 Luna scores DeepSWE 1.1: 66.6%, OSWorld 2.0: 52.7%, Agents' Last Exam: 50.9%, FrontierCode 1.1: 42.4%, AutomationBench v1.0.6: 20.7%.

What are the context window sizes for GPT-5 Codex and GPT-6 Luna?

GPT-5 Codex supports an unknown number of tokens and GPT-6 Luna supports 1.1M 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 GPT-6 Luna?

Key differences include LLM Stats Score (26.6 vs 44.5), multimodal support (no vs yes). See the full comparison above for benchmark-by-benchmark results.

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