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GPT-5 mini vs Grok-4.1 Fast Reasoning

Comparing GPT-5 mini and Grok-4.1 Fast Reasoning across benchmarks, pricing, and capabilities.

OpenAI · xAI · Updated for 2026

Which is better?

GPT-5 mini and Grok-4.1 Fast Reasoning trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.

On price, Grok-4.1 Fast Reasoning is roughly 2.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Grok-4.1 Fast Reasoning also accepts a larger context window (2,000,000 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 mini

  • you want predictable pricing at $0.25/M input and $2.00/M output

Choose Grok-4.1 Fast Reasoning

  • cost matters — it's about 2.5x cheaper per token
  • you process long inputs — it offers a 2,000,000 token context window
  • you want the most recent training data — it shipped Nov 2025

At a glance

The differences that matter most.

GPT-5 mini
OpenAI
Grok-4.1 Fast Reasoning
xAI
Benchmark wins
—
—
Input price
$0.25 / M
$0.20 / M
Output price
$2.00 / M
$0.50 / M
Context window
400,000
2,000,000

Individual benchmarks

5 reported for GPT-5 mini · 0 for Grok-4.1 Fast Reasoning

No common benchmarks found

GPT-5 mini and Grok-4.1 Fast Reasoningdon'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

Grok-4.1 Fast Reasoning costs less

For input processing, GPT-5 mini ($0.25/1M tokens) is 1.3x more expensive than Grok-4.1 Fast Reasoning ($0.20/1M tokens).

For output processing, GPT-5 mini ($2.00/1M tokens) is 4.0x more expensive than Grok-4.1 Fast Reasoning ($0.50/1M tokens).

In conclusion, GPT-5 mini is more expensive than Grok-4.1 Fast Reasoning.*

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

Lowest available price from all providers
Mon Sep 14 2026 • llm-stats.com
OpenAI
GPT-5 mini
Input tokens$0.25
Output tokens$2.00
Best providerOpenAI
xAI
Grok-4.1 Fast Reasoning
Input tokens$0.20
Output tokens$0.50
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Grok-4.1 Fast Reasoning accepts 2,000,000 input tokens compared to GPT-5 mini's 400,000 tokens. GPT-5 mini can generate longer responses up to 128,000 tokens, while Grok-4.1 Fast Reasoning is limited to 30,000 tokens.

OpenAI
GPT-5 mini
Input400,000 tokens
Output128,000 tokens
xAI
Grok-4.1 Fast Reasoning
Input2,000,000 tokens
Output30,000 tokens
Mon Sep 14 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-5 mini and Grok-4.1 Fast Reasoning support multimodal inputs.

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

GPT-5 mini

Text
Images
Audio
Video

Grok-4.1 Fast Reasoning

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 mini

Proprietary

Closed source

Grok-4.1 Fast Reasoning

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5 mini was released on 2025-08-07, while Grok-4.1 Fast Reasoning was released on 2025-11-17.

Grok-4.1 Fast Reasoning is 3 months newer than GPT-5 mini.

GPT-5 mini

Aug 7, 2025

1.1 years ago

Grok-4.1 Fast Reasoning

Nov 17, 2025

10 months ago

3mo newer

Knowledge Cutoff

When training data ends

GPT-5 mini has a documented knowledge cutoff of 2024-05-30, while Grok-4.1 Fast Reasoning's cutoff date is not specified.

We can confirm GPT-5 mini's training data extends to 2024-05-30, but cannot make a direct comparison without Grok-4.1 Fast Reasoning's cutoff date.

GPT-5 mini

May 2024

Grok-4.1 Fast Reasoning

—

Provider Availability

GPT-5 mini is available from OpenAI. Grok-4.1 Fast Reasoning is available from xAI.

GPT-5 mini

openai logo
OpenAI
Input Price:Input: $0.25/1MOutput Price:Output: $2.00/1M

Grok-4.1 Fast Reasoning

xai logo
xAI
Input Price:Input: $0.20/1MOutput Price:Output: $0.50/1M
* 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-5 mini and Grok-4.1 Fast Reasoning side-by-side, then vote on the output you prefer.

GPT-5 mini
✓ Preferred
Grok-4.1 Fast Reasoning
Open in Playground

FAQ

Common questions about GPT-5 mini vs Grok-4.1 Fast Reasoning.

Which is better, GPT-5 mini or Grok-4.1 Fast Reasoning?

GPT-5 mini (OpenAI) and Grok-4.1 Fast Reasoning (xAI) 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 mini compare to Grok-4.1 Fast Reasoning in benchmarks?

GPT-5 mini scores AIME 2025: 91.1%, HMMT 2025: 87.8%, GPQA: 82.3%, FrontierMath: 22.1%, Humanity's Last Exam: 16.7%.

Is GPT-5 mini cheaper than Grok-4.1 Fast Reasoning?

Grok-4.1 Fast Reasoning is 1.3x cheaper for input tokens. GPT-5 mini costs $0.25/M input and $2.00/M output via openai. Grok-4.1 Fast Reasoning costs $0.20/M input and $0.50/M output via xai.

What are the context window sizes for GPT-5 mini and Grok-4.1 Fast Reasoning?

GPT-5 mini supports 400K tokens and Grok-4.1 Fast Reasoning supports 2.0M 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 mini and Grok-4.1 Fast Reasoning?

Key differences include context window (400K vs 2.0M), input pricing ($0.25 vs $0.20/M). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5 mini and Grok-4.1 Fast Reasoning?

GPT-5 mini is developed by OpenAI and Grok-4.1 Fast Reasoning is developed by xAI.

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