Model Comparison

Grok-1.5 vs o3-proWhich is better in 2026?

Comparing Grok-1.5 and o3-pro across benchmarks, pricing, and capabilities.

Verdict: Grok-1.5 vs o3-pro — which is better?

Grok-1.5 (by xAI) and o3-pro (by OpenAI) 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.

Choose Grok-1.5 if…

  • you are already invested in the xAI ecosystem

Choose o3-pro if…

  • you want the most recent training data — it shipped Jun 2025

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Grok-1.5 and o3-prodon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only o3-pro specifies input context (200,000 tokens). Only o3-pro specifies output context (100,000 tokens).

xAI
Grok-1.5
Input- tokens
Output- tokens
OpenAI
o3-pro
Input200,000 tokens
Output100,000 tokens
Sun Jul 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

o3-pro supports multimodal inputs, whereas Grok-1.5 does not.

o3-pro can handle both text and other forms of data like images, making it suitable for multimodal applications.

Grok-1.5

Text
Images
Audio
Video

o3-pro

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

o3-pro

Proprietary

Closed source

Release Timeline

When each model was launched

Grok-1.5 was released on 2024-03-28, while o3-pro was released on 2025-06-10.

o3-pro is 15 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.3 years ago

o3-pro

Jun 10, 2025

1.1 years ago

1.2yr newer

Knowledge Cutoff

When training data ends

o3-pro has a documented knowledge cutoff of 2024-05-31, while Grok-1.5's cutoff date is not specified.

We can confirm o3-pro's training data extends to 2024-05-31, but cannot make a direct comparison without Grok-1.5's cutoff date.

Grok-1.5

—

o3-pro

May 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.

OpenAI
Larger context window (200,000 tokens)
Supports multimodal inputs

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok-1.5 and o3-pro side-by-side, then vote on the output you prefer.

Grok-1.5
✓ Preferred
o3-pro
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok-1.5
OpenAI
o3-pro

FAQ

Common questions about Grok-1.5 vs o3-pro.

Which is better, Grok-1.5 or o3-pro?

Grok-1.5 (xAI) and o3-pro (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Grok-1.5 compare to o3-pro in benchmarks?

Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%.

What are the context window sizes for Grok-1.5 and o3-pro?

Grok-1.5 supports an unknown number of tokens and o3-pro supports 200K 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 o3-pro?

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

Who makes Grok-1.5 and o3-pro?

Grok-1.5 is developed by xAI and o3-pro is developed by OpenAI.

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