Model Comparison

GPT-5 Codex vs Kimi K3Which is better in 2026?

Comparing GPT-5 Codex and Kimi K3 across benchmarks, pricing, and capabilities.

Verdict: GPT-5 Codex vs Kimi K3 — which is better?

GPT-5 Codex (by OpenAI) and Kimi K3 (by Moonshot AI) 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 Codex if…

  • you are already invested in the OpenAI ecosystem

Choose Kimi K3 if…

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

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

GPT-5 Codex and Kimi K3don'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 Kimi K3 specifies input context (1,048,576 tokens). Only Kimi K3 specifies output context (1,048,576 tokens).

OpenAI
GPT-5 Codex
Input- tokens
Output- tokens
Moonshot AI
Kimi K3
Input1,048,576 tokens
Output1,048,576 tokens
Sun Jul 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Kimi K3 supports multimodal inputs, whereas GPT-5 Codex does not.

Kimi K3 can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5 Codex

Text
Images
Audio
Video

Kimi K3

Text
Images
Audio
Video

Release Timeline

When each model was launched

GPT-5 Codex was released on 2025-09-15, while Kimi K3 was released on 2026-07-16.

Kimi K3 is 10 months newer than GPT-5 Codex.

GPT-5 Codex

Sep 15, 2025

10 months ago

Kimi K3

Jul 16, 2026

1 weeks ago

10mo newer

Knowledge Cutoff

When training data ends

GPT-5 Codex has a documented knowledge cutoff of 2024-09-30, while Kimi K3'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 Kimi K3's cutoff date.

GPT-5 Codex

Sep 2024

Kimi K3

—

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI

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

Moonshot AI
Larger context window (1,048,576 tokens)
Supports multimodal inputs
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-5 Codex and Kimi K3 side-by-side, then vote on the output you prefer.

GPT-5 Codex
✓ Preferred
Kimi K3
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-5 Codex
Moonshot AI
Kimi K3

FAQ

Common questions about GPT-5 Codex vs Kimi K3.

Which is better, GPT-5 Codex or Kimi K3?

GPT-5 Codex (OpenAI) and Kimi K3 (Moonshot AI) 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 Kimi K3 in benchmarks?

GPT-5 Codex scores SWE-Bench Verified: 74.5%. Kimi K3 scores MathVision: 97.8%, DeepSearchQA: 95.0%, GPQA: 93.5%, CharXiv-R: 91.3%, BrowseComp: 91.2%.

What are the context window sizes for GPT-5 Codex and Kimi K3?

GPT-5 Codex supports an unknown number of tokens and Kimi K3 supports 1.0M 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 Kimi K3?

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

Who makes GPT-5 Codex and Kimi K3?

GPT-5 Codex is developed by OpenAI and Kimi K3 is developed by Moonshot AI.

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