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GPT-5 mini vs Grok-4 Heavy

Grok-4 Heavy leads the LLM Stats Score 40.7 to 27.3.

OpenAI · xAI · Updated for 2026

Which is better?

Grok-4 Heavy leads the overall LLM Stats Score 40.7 to 27.3, ranking #59 overall.

In the 3 individual benchmarks reported for both models, Grok-4 Heavy wins 3; this is a narrower head-to-head signal than the composite indexes.

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 Heavy

  • overall performance matters — it scores 40.7 and ranks #59 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 3 of 3 exact shared results

At a glance

The differences that matter most.

Core performance indexes
27.3
#150
40.7
#59
26.6
#150
39.0
#63
Cost, coverage & limits
Benchmark wins
0 of 3
3 of 3
Input price
$0.25 / M
— / M
Output price
$2.00 / M
— / M
Context window
400,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
GPT-5 mini
Grok-4 Heavy
25.6#107
41.5#7
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

5 reported for GPT-5 mini · 6 for Grok-4 Heavy

3 shared

GPT-5 mini outperforms in 0 benchmarks, while Grok-4 Heavy is better at 3 benchmarks (AIME 2025, GPQA, Humanity's Last Exam).

Grok-4 Heavy significantly outperforms across most benchmarks.

Wed Sep 23 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only GPT-5 mini specifies input context (400,000 tokens). Only GPT-5 mini specifies output context (128,000 tokens).

OpenAI
GPT-5 mini
Input400,000 tokens
Output128,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Wed Sep 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both GPT-5 mini and Grok-4 Heavy 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 Heavy

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 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5 mini was released on 2025-08-07, while Grok-4 Heavy's release date is not specified.

We can confirm GPT-5 mini's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

GPT-5 mini

Aug 7, 2025

1.1 years ago

Grok-4 Heavy

Knowledge Cutoff

When training data ends

GPT-5 mini has a knowledge cutoff of 2024-05-30, while Grok-4 Heavy has a cutoff of 2024-12-31.

Grok-4 Heavy has more recent training data (up to 2024-12-31), making it potentially better informed about events through that date compared to GPT-5 mini (2024-05-30).

GPT-5 mini

May 2024

Grok-4 Heavy

Dec 2024

7 mo newer

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 Heavy side-by-side, then vote on the output you prefer.

GPT-5 mini
✓ Preferred
Grok-4 Heavy
Open in Playground

FAQ

Common questions about GPT-5 mini vs Grok-4 Heavy.

Which is better, GPT-5 mini or Grok-4 Heavy?

Grok-4 Heavy leads the LLM Stats Score 40.7 to 27.3. GPT-5 mini is made by OpenAI and Grok-4 Heavy is made by xAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does GPT-5 mini compare to Grok-4 Heavy 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%. Grok-4 Heavy scores AIME 2025: 100.0%, HMMT25: 96.7%, GPQA: 88.4%, LiveCodeBench: 79.4%, USAMO25: 61.9%.

What are the context window sizes for GPT-5 mini and Grok-4 Heavy?

GPT-5 mini supports 400K tokens and Grok-4 Heavy supports an unknown number of 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 Heavy?

Key differences include LLM Stats Score (27.3 vs 40.7). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5 mini and Grok-4 Heavy?

GPT-5 mini is developed by OpenAI and Grok-4 Heavy is developed by xAI.