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GPT-4.1 mini vs GPT-5.1 Codex Mini

GPT-4.1 mini and GPT-5.1 Codex Mini are closely matched at 13.5 and -3.1 on the LLM Stats Score. GPT-5.1 Codex Mini is 1.0x cheaper per token.

OpenAI · OpenAI · Updated for 2026

Which is better?

GPT-4.1 mini and GPT-5.1 Codex Mini are closely matched on the overall LLM Stats Score at 13.5 and -3.1.

In the 1 individual benchmarks reported for both models, GPT-5.1 Codex Mini wins 1; this is a narrower head-to-head signal than the composite indexes.

GPT-4.1 mini also accepts a larger context window (1,047,576 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-4.1 mini

  • you process long inputs — it offers a 1,047,576 token context window

Choose GPT-5.1 Codex Mini

  • you value its reported benchmark strengths — it wins 1 of 1 exact shared results
  • you want the most recent training data — it shipped Nov 2025

At a glance

The differences that matter most.

GPT-4.1 mini
OpenAI
GPT-5.1 Codex Mini
OpenAI
Core performance indexes
LLM Stats Score
13.5
#265
-3.1
#366
Reasoning
13.4
#258
-3.0
#358
Cost, coverage & limits
Benchmark wins
0 of 1
1 of 1
Input price
$0.40 / M
$0.25 / M
Output price
$1.60 / M
$2.00 / M
Context window
1,047,576
400,000

Individual benchmarks

28 reported for GPT-4.1 mini · 1 for GPT-5.1 Codex Mini

1 shared

GPT-4.1 mini outperforms in 0 benchmarks, while GPT-5.1 Codex Mini is better at 1 benchmark (AIME 2025).

GPT-5.1 Codex Mini significantly outperforms across most benchmarks.

Fri Oct 23 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

GPT-5.1 Codex Mini costs less

For input processing, GPT-4.1 mini ($0.40/1M tokens) is 1.6x more expensive than GPT-5.1 Codex Mini ($0.25/1M tokens).

For output processing, GPT-4.1 mini ($1.60/1M tokens) is 1.3x cheaper than GPT-5.1 Codex Mini ($2.00/1M tokens).

In conclusion, GPT-4.1 mini is more expensive than GPT-5.1 Codex Mini.*

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

Lowest available price from all providers
Fri Oct 23 2026 • llm-stats.com
OpenAI
GPT-4.1 mini
Input tokens$0.40
Output tokens$1.60
Best providerOpenAI
OpenAI
GPT-5.1 Codex Mini
Input tokens$0.25
Output tokens$2.00
Best providerOpenAI
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

GPT-4.1 mini accepts 1,047,576 input tokens compared to GPT-5.1 Codex Mini's 400,000 tokens. GPT-5.1 Codex Mini can generate longer responses up to 128,000 tokens, while GPT-4.1 mini is limited to 32,768 tokens.

OpenAI
GPT-4.1 mini
Input1,047,576 tokens
Output32,768 tokens
OpenAI
GPT-5.1 Codex Mini
Input400,000 tokens
Output128,000 tokens
Fri Oct 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-4.1 mini and GPT-5.1 Codex Mini support multimodal inputs.

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

GPT-4.1 mini

Text
Images
Audio
Video

GPT-5.1 Codex Mini

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-4.1 mini

Proprietary

Closed source

GPT-5.1 Codex Mini

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-4.1 mini was released on 2025-04-14, while GPT-5.1 Codex Mini was released on 2025-11-12.

GPT-5.1 Codex Mini is 7 months newer than GPT-4.1 mini.

GPT-4.1 mini

Apr 14, 2025

1.5 years ago

GPT-5.1 Codex Mini

Nov 12, 2025

11 months ago

7mo newer

Knowledge Cutoff

When training data ends

GPT-4.1 mini has a documented knowledge cutoff of 2024-05-31, while GPT-5.1 Codex Mini's cutoff date is not specified.

We can confirm GPT-4.1 mini's training data extends to 2024-05-31, but cannot make a direct comparison without GPT-5.1 Codex Mini's cutoff date.

GPT-4.1 mini

May 2024

GPT-5.1 Codex Mini

—

Provider Availability

GPT-4.1 mini is available from OpenAI. GPT-5.1 Codex Mini is available from OpenAI.

GPT-4.1 mini

openai logo
OpenAI
Input Price:Input: $0.40/1MOutput Price:Output: $1.60/1M

GPT-5.1 Codex Mini

openai logo
OpenAI
Input Price:Input: $0.25/1MOutput Price:Output: $2.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against GPT-4.1 mini and GPT-5.1 Codex Mini side-by-side, then vote on the output you prefer.

GPT-4.1 mini
✓ Preferred
GPT-5.1 Codex Mini
Open in Playground

FAQ

Common questions about GPT-4.1 mini vs GPT-5.1 Codex Mini.

Which is better, GPT-4.1 mini or GPT-5.1 Codex Mini?

GPT-4.1 mini and GPT-5.1 Codex Mini are closely matched on the LLM Stats Score at 13.5 and -3.1. GPT-4.1 mini is made by OpenAI and GPT-5.1 Codex Mini 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-4.1 mini compare to GPT-5.1 Codex Mini in benchmarks?

GPT-4.1 mini scores CharXiv-D: 88.4%, MMLU: 87.5%, IFEval: 84.1%, MMMLU: 78.5%, MathVista: 73.1%. GPT-5.1 Codex Mini scores AIME 2025: 42.1%.

Is GPT-4.1 mini cheaper than GPT-5.1 Codex Mini?

GPT-5.1 Codex Mini is 1.6x cheaper for input tokens. GPT-4.1 mini costs $0.40/M input and $1.60/M output via openai. GPT-5.1 Codex Mini costs $0.25/M input and $2.00/M output via openai.

What are the context window sizes for GPT-4.1 mini and GPT-5.1 Codex Mini?

GPT-4.1 mini supports 1.0M tokens and GPT-5.1 Codex Mini supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-4.1 mini and GPT-5.1 Codex Mini?

Key differences include LLM Stats Score (13.5 vs -3.1), context window (1.0M vs 400K), input pricing ($0.40 vs $0.25/M). See the full comparison above for benchmark-by-benchmark results.

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