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Grok-1.5 vs Mercury 3

Mercury 3 leads the LLM Stats Score 36.1 to -3.1.

xAI · Inception · Updated for 2026

Which is better?

Mercury 3 leads the overall LLM Stats Score 36.1 to -3.1, ranking #98 overall.

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-1.5

  • you are already invested in the xAI ecosystem

Choose Mercury 3

  • overall performance matters — it scores 36.1 and ranks #98 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 1 of 1 exact shared results
  • you want the most recent training data — it shipped Oct 2026

At a glance

The differences that matter most.

Grok-1.5
xAI
Mercury 3
Inception
Core performance indexes
LLM Stats Score
-3.1
#367
36.1
#98
Reasoning
-2.7
#357
34.8
#103
Coding
-1.0
#271
21.5
#105
Cost, coverage & limits
Benchmark wins
0 of 1
1 of 1
Input price
— / M
$0.10 / M
Output price
— / M
$0.35 / M
Context window
—
1,000,000

Individual benchmarks

9 reported for Grok-1.5 · 12 for Mercury 3

1 shared

Grok-1.5 outperforms in 0 benchmarks, while Mercury 3 is better at 1 benchmark (GPQA).

Mercury 3 significantly outperforms across most benchmarks.

Thu Oct 22 2026 • llm-stats.com

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).

xAI
Grok-1.5
Input- tokens
Output- tokens
Inception
Mercury 3
Input1,000,000 tokens
Output131,072 tokens
Thu Oct 22 2026 • llm-stats.com

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Grok-1.5

Proprietary

Closed source

Mercury 3

Proprietary

Closed source

Release Timeline

When each model was launched

Grok-1.5 was released on 2024-03-28, while Mercury 3 was released on 2026-10-19.

Mercury 3 is 31 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.6 years ago

Mercury 3

Oct 19, 2026

0 days ago

2.6yr newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Grok-1.5 and Mercury 3 side-by-side, then vote on the output you prefer.

Grok-1.5
✓ Preferred
Mercury 3
Open in Playground

FAQ

Common questions about Grok-1.5 vs Mercury 3.

Which is better, Grok-1.5 or Mercury 3?

Mercury 3 leads the LLM Stats Score 36.1 to -3.1. Grok-1.5 is made by xAI and Mercury 3 is made by Inception. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Grok-1.5 compare to Mercury 3 in benchmarks?

Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%. Mercury 3 scores GPQA: 89.2%, AA-LCR: 77.7%, IFBench: 76.8%, MRCR v2: 75.5%, DeepSearchQA: 71.3%.

What are the context window sizes for Grok-1.5 and Mercury 3?

Grok-1.5 supports an unknown number of tokens and Mercury 3 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Grok-1.5 and Mercury 3?

Key differences include LLM Stats Score (-3.1 vs 36.1). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok-1.5 and Mercury 3?

Grok-1.5 is developed by xAI and Mercury 3 is developed by Inception.

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