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GPT-5.1 Codex High vs Kimi K3.1 Pro

Kimi K3.1 Pro leads the LLM Stats Score 55.5 to 29.0. GPT-5.1 Codex High is 1.2x cheaper per token.

OpenAI · Moonshot AI · Updated for 2026

Which is better?

Kimi K3.1 Pro leads the overall LLM Stats Score 55.5 to 29.0, ranking #5 overall.

On price, GPT-5.1 Codex High is roughly 1.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Kimi K3.1 Pro also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.

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

Choose GPT-5.1 Codex High

  • cost matters — it's about 1.2x cheaper per token

Choose Kimi K3.1 Pro

  • overall performance matters — it scores 55.5 and ranks #5 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you process long inputs — it offers a 1,048,576 token context window
  • you want the most recent training data — it shipped Oct 2026

At a glance

The differences that matter most.

GPT-5.1 Codex High
OpenAI
Kimi K3.1 Pro
Moonshot AI
Core performance indexes
LLM Stats Score
29.0
#160
55.5
#5
Reasoning
28.8
#153
54.3
#6
Cost, coverage & limits
Benchmark wins
—
—
Input price
$1.25 / M
$2.00 / M
Output price
$10.00 / M
$10.00 / M
Context window
400,000
1,048,576

Individual benchmarks

1 reported for GPT-5.1 Codex High · 30 for Kimi K3.1 Pro

No common benchmarks found

GPT-5.1 Codex High and Kimi K3.1 Prodon'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

Pricing Analysis

Price comparison per million tokens

GPT-5.1 Codex High costs less

For input processing, GPT-5.1 Codex High ($1.25/1M tokens) is 1.6x cheaper than Kimi K3.1 Pro ($2.00/1M tokens).

For output processing, GPT-5.1 Codex High ($10.00/1M tokens) costs the same as Kimi K3.1 Pro ($10.00/1M tokens).

In conclusion, Kimi K3.1 Pro is more expensive than GPT-5.1 Codex High.*

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

Lowest available price from all providers
Sat Oct 31 2026 • llm-stats.com
OpenAI
GPT-5.1 Codex High
Input tokens$1.25
Output tokens$10.00
Best providerOpenAI
Moonshot AI
Kimi K3.1 Pro
Input tokens$2.00
Output tokens$10.00
Best providerUnknown Organization
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Kimi K3.1 Pro accepts 1,048,576 input tokens compared to GPT-5.1 Codex High's 400,000 tokens. Kimi K3.1 Pro can generate longer responses up to 1,048,576 tokens, while GPT-5.1 Codex High is limited to 128,000 tokens.

OpenAI
GPT-5.1 Codex High
Input400,000 tokens
Output128,000 tokens
Moonshot AI
Kimi K3.1 Pro
Input1,048,576 tokens
Output1,048,576 tokens
Sat Oct 31 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-5.1 Codex High and Kimi K3.1 Pro support multimodal inputs.

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

GPT-5.1 Codex High

Text
Images
Audio
Video

Kimi K3.1 Pro

Text
Images
Audio
Video

Release Timeline

When each model was launched

GPT-5.1 Codex High was released on 2025-11-12, while Kimi K3.1 Pro was released on 2026-10-23.

Kimi K3.1 Pro is 12 months newer than GPT-5.1 Codex High.

GPT-5.1 Codex High

Nov 12, 2025

11 months ago

Kimi K3.1 Pro

Oct 23, 2026

1 weeks ago

11mo newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

GPT-5.1 Codex High is available from OpenAI. Kimi K3.1 Pro is available from Moonshot AI.

GPT-5.1 Codex High

openai logo
OpenAI
Input Price:Input: $1.25/1MOutput Price:Output: $10.00/1M

Kimi K3.1 Pro

moonshot logo
Unknown Organization
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against GPT-5.1 Codex High and Kimi K3.1 Pro side-by-side, then vote on the output you prefer.

GPT-5.1 Codex High
✓ Preferred
Kimi K3.1 Pro
Open in Playground

FAQ

Common questions about GPT-5.1 Codex High vs Kimi K3.1 Pro.

Which is better, GPT-5.1 Codex High or Kimi K3.1 Pro?

Kimi K3.1 Pro leads the LLM Stats Score 55.5 to 29.0. GPT-5.1 Codex High is made by OpenAI and Kimi K3.1 Pro is made by Moonshot AI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5.1 Codex High compare to Kimi K3.1 Pro in benchmarks?

GPT-5.1 Codex High scores AIME 2025: 96.7%. Kimi K3.1 Pro scores BabyVision: 95.4%, GPQA: 94.2%, BenchCAD (with Python tool): 92.7%, BrowseComp: 92.1%, Chartography: 90.2%.

Is GPT-5.1 Codex High cheaper than Kimi K3.1 Pro?

GPT-5.1 Codex High is 1.6x cheaper for input tokens. GPT-5.1 Codex High costs $1.25/M input and $10.00/M output via openai. Kimi K3.1 Pro costs $2.00/M input and $10.00/M output via moonshot.

What are the context window sizes for GPT-5.1 Codex High and Kimi K3.1 Pro?

GPT-5.1 Codex High supports 400K tokens and Kimi K3.1 Pro 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-5.1 Codex High and Kimi K3.1 Pro?

Key differences include LLM Stats Score (29.0 vs 55.5), context window (400K vs 1.0M), input pricing ($1.25 vs $2.00/M), licensing (Proprietary vs Unknown). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.1 Codex High and Kimi K3.1 Pro?

GPT-5.1 Codex High is developed by OpenAI and Kimi K3.1 Pro is developed by Moonshot AI.

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