Grok-4 Heavy vs Mercury 3
Grok-4 Heavy and Mercury 3 are closely matched at 40.6 and 36.1 on the LLM Stats Score.
xAI · Inception · Updated for 2026
Which is better?
Grok-4 Heavy and Mercury 3 are closely matched on the overall LLM Stats Score at 40.6 and 36.1.
In the 1 individual benchmarks reported for both models, Mercury 3 wins 1; 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 Heavy
- you are already invested in the xAI ecosystem
Choose Mercury 3
- you value its reported benchmark strengths — it wins 1 of 1 exact shared results
At a glance
The differences that matter most.
Individual benchmarks
6 reported for Grok-4 Heavy · 12 for Mercury 3
Grok-4 Heavy outperforms in 0 benchmarks, while Mercury 3 is better at 1 benchmark (GPQA).
Mercury 3 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Context Window
Maximum input and output token capacity
Only Mercury 3 specifies input context (1,000,000 tokens). Only Mercury 3 specifies output context (131,072 tokens).
Input capabilities
Documented input modalities across available providers
Grok-4 Heavy supports multimodal inputs, whereas Mercury 3 does not.
Grok-4 Heavy can handle both text and other forms of data like images, making it suitable for multimodal applications.
Grok-4 Heavy
Mercury 3
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Mercury 3 was released on 2026-10-19, while Grok-4 Heavy's release date is not specified.
We can confirm Mercury 3's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.
—
Oct 19, 2026
1 days ago
Knowledge Cutoff
When training data ends
Grok-4 Heavy has a documented knowledge cutoff of 2024-12-31, while Mercury 3's cutoff date is not specified.
We can confirm Grok-4 Heavy's training data extends to 2024-12-31, but cannot make a direct comparison without Mercury 3's cutoff date.
Dec 2024
—
Outputs Comparison
Judge for yourself.
Run your own prompts against Grok-4 Heavy and Mercury 3 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Grok-4 Heavy vs Mercury 3.