Model Comparison

Gemini 2.5 Flash vs Grok-1.5

Gemini 2.5 Flash significantly outperforms across most benchmarks.

Want to compare interactively?Try the playground

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Gemini 2.5 Flash outperforms in 2 benchmarks (GPQA, MMMU), while Grok-1.5 is better at 0 benchmarks.

Gemini 2.5 Flash significantly outperforms across most benchmarks.

Tue May 12 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Gemini 2.5 Flash specifies input context (1,048,576 tokens). Only Gemini 2.5 Flash specifies output context (65,536 tokens).

Google
Gemini 2.5 Flash
Input1,048,576 tokens
Output65,536 tokens
xAI
Grok-1.5
Input- tokens
Output- tokens
Tue May 12 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Gemini 2.5 Flash supports multimodal inputs, whereas Grok-1.5 does not.

Gemini 2.5 Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.

Gemini 2.5 Flash

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.

Gemini 2.5 Flash

Proprietary

Closed source

Grok-1.5

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 2.5 Flash was released on 2025-05-20, while Grok-1.5 was released on 2024-03-28.

Gemini 2.5 Flash is 14 months newer than Grok-1.5.

Gemini 2.5 Flash

May 20, 2025

11 months ago

1.1yr newer
Grok-1.5

Mar 28, 2024

2.1 years ago

Knowledge Cutoff

When training data ends

Gemini 2.5 Flash has a documented knowledge cutoff of 2025-01-31, while Grok-1.5's cutoff date is not specified.

We can confirm Gemini 2.5 Flash's training data extends to 2025-01-31, but cannot make a direct comparison without Grok-1.5's cutoff date.

Gemini 2.5 Flash

Jan 2025

Grok-1.5

—

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Google
Larger context window (1,048,576 tokens)
Supports multimodal inputs
Higher GPQA score (82.8% vs 35.9%)
Higher MMMU score (79.7% vs 53.6%)
xAI

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

GoogleGemini 2.5 Flash
xAIGrok-1.5
Compare in Playground

Detailed Comparison

AI Model Comparison Table
Feature
Google
Gemini 2.5 Flash
xAI
Grok-1.5

FAQ

Common questions about Gemini 2.5 Flash vs Grok-1.5.

Which is better, Gemini 2.5 Flash or Grok-1.5?

Gemini 2.5 Flash significantly outperforms across most benchmarks. Gemini 2.5 Flash is made by Google 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 Gemini 2.5 Flash compare to Grok-1.5 in benchmarks?

Gemini 2.5 Flash scores Global-MMLU-Lite: 88.4%, AIME 2024: 88.0%, FACTS Grounding: 85.3%, GPQA: 82.8%, MMMU: 79.7%. 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 Gemini 2.5 Flash and Grok-1.5?

Gemini 2.5 Flash supports 1.0M 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 Gemini 2.5 Flash and Grok-1.5?

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

Who makes Gemini 2.5 Flash and Grok-1.5?

Gemini 2.5 Flash is developed by Google and Grok-1.5 is developed by xAI.