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GPT-4.1 mini vs GPT-5.1 Codex Mini

GPT-5.1 Codex Mini significantly outperforms across most benchmarks. GPT-5.1 Codex Mini is 1.0x cheaper per token.

OpenAI · OpenAI · Updated for 2026

Which is better?

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.

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 benchmark, 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 want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • 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
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
Released
Apr 2025
Nov 2025
License
Proprietary
Proprietary

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

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.

Wed Aug 26 2026 • llm-stats.com

Arena Performance

Playground indexes and blind 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
Wed Aug 26 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?Start an Issue→

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
Wed Aug 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

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

1.4 years ago

GPT-5.1 Codex Mini

Nov 12, 2025

9 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?Start an Issue discussion→

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-5.1 Codex Mini significantly outperforms across most benchmarks. 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 benchmark scores, pricing, and capabilities 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 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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