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Grok-4 vs Grok-4 Heavy

Grok-4 Heavy leads the LLM Stats Score 40.9 to 33.9.

xAI · xAI · Updated for 2026

Which is better?

Grok-4 Heavy leads the overall LLM Stats Score 40.9 to 33.9, ranking #50 overall.

In the 6 individual benchmarks reported for both models, Grok-4 Heavy wins 6; 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 Grok-4

  • you want predictable pricing at $3.00/M input and $15.00/M output

Choose Grok-4 Heavy

  • overall performance matters — it scores 40.9 and ranks #50 on LLM Stats
  • you value its reported benchmark strengths — it wins 6 of 6 exact shared results

At a glance

The differences that matter most.

Core performance indexes
33.9
#90
40.9
#50
33.1
#91
39.2
#53
17.4
#115
17.9
#108
Cost, coverage & limits
Benchmark wins
0 of 6
6 of 6
Input price
$3.00 / M
— / M
Output price
$15.00 / M
— / M
Context window
256,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Grok-4
Grok-4 Heavy
31.4#63
41.4#6
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

7 reported for Grok-4 · 6 for Grok-4 Heavy

6 shared

Grok-4 outperforms in 0 benchmarks, while Grok-4 Heavy is better at 6 benchmarks (AIME 2025, GPQA, HMMT25, Humanity's Last Exam, LiveCodeBench, USAMO25).

Grok-4 Heavy significantly outperforms across most benchmarks.

Sun Sep 06 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Grok-4 specifies input context (256,000 tokens). Only Grok-4 specifies output context (8,000 tokens).

xAI
Grok-4
Input256,000 tokens
Output8,000 tokens
xAI
Grok-4 Heavy
Input- tokens
Output- tokens
Sun Sep 06 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Grok-4 and Grok-4 Heavy support multimodal inputs.

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

Grok-4

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.

Grok-4

Proprietary

Closed source

Grok-4 Heavy

Proprietary

Closed source

Release Timeline

When each model was launched

Grok-4 was released on 2025-07-09, while Grok-4 Heavy's release date is not specified.

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

Grok-4

Jul 9, 2025

1.2 years ago

Grok-4 Heavy

Knowledge Cutoff

When training data ends

Both models have the same knowledge cutoff date of 2024-12-31.

They should have similar awareness of historical events and information up to this date.

Grok-4

Dec 2024

Grok-4 Heavy

Dec 2024

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion

Judge for yourself.

Run your own prompts against Grok-4 and Grok-4 Heavy side-by-side, then vote on the output you prefer.

Grok-4
✓ Preferred
Grok-4 Heavy
Open in Playground

FAQ

Common questions about Grok-4 vs Grok-4 Heavy.

Which is better, Grok-4 or Grok-4 Heavy?

Grok-4 Heavy leads the LLM Stats Score 40.9 to 33.9. Grok-4 is made by xAI 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 Grok-4 compare to Grok-4 Heavy in benchmarks?

Grok-4 scores AIME 2025: 91.7%, HMMT25: 90.0%, GPQA: 87.5%, LiveCodeBench: 79.0%, Humanity's Last Exam: 40.0%. 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 Grok-4 and Grok-4 Heavy?

Grok-4 supports 256K 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 Grok-4 and Grok-4 Heavy?

Key differences include LLM Stats Score (33.9 vs 40.9). See the full comparison above for benchmark-by-benchmark results.