Model Comparison

Grok-1.5 vs Grok-3Which is better in 2026?

Grok-3 significantly outperforms across most benchmarks.

Verdict: Grok-1.5 vs Grok-3 — which is better?

Grok-1.5 (by xAI) and Grok-3 (by xAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Grok-1.5 outperforms in 0 benchmarks, while Grok-3 is better at 2 benchmarks (GPQA, MMMU). Grok-3 significantly outperforms across most benchmarks.

Choose Grok-1.5 if…

  • you are already invested in the xAI ecosystem

Choose Grok-3 if…

  • you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
  • you want the most recent training data — it shipped Feb 2025

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Grok-1.5 outperforms in 0 benchmarks, while Grok-3 is better at 2 benchmarks (GPQA, MMMU).

Grok-3 significantly outperforms across most benchmarks.

Fri Jul 03 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Grok-3 specifies input context (128,000 tokens). Only Grok-3 specifies output context (8,000 tokens).

xAI
Grok-1.5
Input- tokens
Output- tokens
xAI
Grok-3
Input128,000 tokens
Output8,000 tokens
Fri Jul 03 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Grok-3 supports multimodal inputs, whereas Grok-1.5 does not.

Grok-3 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Grok-1.5

Text
Images
Audio
Video

Grok-3

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-1.5

Proprietary

Closed source

Grok-3

Proprietary

Closed source

Release Timeline

When each model was launched

Grok-1.5 was released on 2024-03-28, while Grok-3 was released on 2025-02-17.

Grok-3 is 11 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.3 years ago

Grok-3

Feb 17, 2025

1.4 years ago

10mo newer

Knowledge Cutoff

When training data ends

Grok-3 has a documented knowledge cutoff of 2024-11-17, while Grok-1.5's cutoff date is not specified.

We can confirm Grok-3's training data extends to 2024-11-17, but cannot make a direct comparison without Grok-1.5's cutoff date.

Grok-1.5

—

Grok-3

Nov 2024

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

xAI

No standout differentiators in the data we have for this pair.

xAI
Larger context window (128,000 tokens)
Supports multimodal inputs
Higher GPQA score (84.6% vs 35.9%)
Higher MMMU score (78.0% vs 53.6%)
xAIGrok-1.5
xAIGrok-3
Compare in Playground

Detailed Comparison

Interactive Arena

Judge for yourself.

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

Grok-1.5
✓ Preferred
Grok-3
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok-1.5
xAI
Grok-3

FAQ

Common questions about Grok-1.5 vs Grok-3.

Which is better, Grok-1.5 or Grok-3?

Grok-3 significantly outperforms across most benchmarks. Grok-1.5 is made by xAI and Grok-3 is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

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

Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%. Grok-3 scores AIME 2024: 93.3%, AIME 2025: 93.3%, GPQA: 84.6%, LiveCodeBench: 79.4%, MMMU: 78.0%.

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

Grok-1.5 supports an unknown number of tokens and Grok-3 supports 128K 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 Grok-3?

Key differences include multimodal support (no vs yes). See the full comparison above for benchmark-by-benchmark results.

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