Model Comparison

GPT-4o vs Grok-1.5Which is better in 2026?

GPT-4o significantly outperforms across most benchmarks.

Verdict: GPT-4o vs Grok-1.5 — which is better?

GPT-4o (by OpenAI) and Grok-1.5 (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.

GPT-4o outperforms in 6 benchmarks (DocVQA, GPQA, MathVista, MMLU, MMLU-Pro, MMMU), while Grok-1.5 is better at 0 benchmarks. GPT-4o significantly outperforms across most benchmarks.

Choose GPT-4o if…

  • you want the strongest raw capability — it leads on 6 of 6 shared benchmarks
  • you want the most recent training data — it shipped Aug 2024

Choose Grok-1.5 if…

  • you are already invested in the xAI ecosystem

Performance Benchmarks

Comparative analysis across standard metrics

6 benchmarks

GPT-4o outperforms in 6 benchmarks (DocVQA, GPQA, MathVista, MMLU, MMLU-Pro, MMMU), while Grok-1.5 is better at 0 benchmarks.

GPT-4o significantly outperforms across most benchmarks.

Wed Jul 01 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-4o specifies input context (128,000 tokens). Only GPT-4o specifies output context (16,384 tokens).

OpenAI
GPT-4o
Input128,000 tokens
Output16,384 tokens
xAI
Grok-1.5
Input- tokens
Output- tokens
Wed Jul 01 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-4o supports multimodal inputs, whereas Grok-1.5 does not.

GPT-4o can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-4o

Text
Images
Audio
Video

Grok-1.5

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.

GPT-4o

Proprietary

Closed source

Grok-1.5

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-4o was released on 2024-08-06, while Grok-1.5 was released on 2024-03-28.

GPT-4o is 4 months newer than Grok-1.5.

GPT-4o

Aug 6, 2024

1.9 years ago

4mo newer
Grok-1.5

Mar 28, 2024

2.3 years ago

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?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (128,000 tokens)
Supports multimodal inputs
Higher DocVQA score (92.8% vs 85.6%)
Higher GPQA score (70.1% vs 35.9%)
Higher MathVista score (61.4% vs 52.8%)
Higher MMLU score (85.7% vs 81.3%)
Higher MMLU-Pro score (74.7% vs 51.0%)
Higher MMMU score (72.2% vs 53.6%)
xAI

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

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-4o and Grok-1.5 side-by-side, then vote on the output you prefer.

GPT-4o
✓ Preferred
Grok-1.5
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-4o
xAI
Grok-1.5

FAQ

Common questions about GPT-4o vs Grok-1.5.

Which is better, GPT-4o or Grok-1.5?

GPT-4o significantly outperforms across most benchmarks. GPT-4o is made by OpenAI and Grok-1.5 is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT-4o compare to Grok-1.5 in benchmarks?

GPT-4o scores AI2D: 94.2%, DocVQA: 92.8%, ChartQA: 85.7%, MMLU: 85.7%, CharXiv-D: 85.3%. 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 GPT-4o and Grok-1.5?

GPT-4o supports 128K tokens and Grok-1.5 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 GPT-4o and Grok-1.5?

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

Who makes GPT-4o and Grok-1.5?

GPT-4o is developed by OpenAI and Grok-1.5 is developed by xAI.

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