Model Comparison

Grok-4 vs Kimi K2 InstructWhich is better in 2026?

Grok-4 significantly outperforms across most benchmarks. Kimi K2 Instruct is 12.0x cheaper per token.

Verdict: Grok-4 vs Kimi K2 Instruct — which is better?

Grok-4 (by xAI) and Kimi K2 Instruct (by Moonshot AI) 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-4 outperforms in 3 benchmarks (AIME 2025, GPQA, Humanity's Last Exam), while Kimi K2 Instruct is better at 0 benchmarks. Grok-4 significantly outperforms across most benchmarks.

On price, Kimi K2 Instruct is roughly 12.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Grok-4 also accepts a larger context window (256,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Grok-4 if…

  • you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
  • you process long inputs — it offers a 256,000 token context window

Choose Kimi K2 Instruct if…

  • cost matters — it's about 12.0x cheaper per token
  • you want the most recent training data — it shipped Jul 2025
  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

Grok-4 outperforms in 3 benchmarks (AIME 2025, GPQA, Humanity's Last Exam), while Kimi K2 Instruct is better at 0 benchmarks.

Grok-4 significantly outperforms across most benchmarks.

Wed Jul 15 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Kimi K2 Instruct costs less

For input processing, Grok-4 ($3.00/1M tokens) is 6.0x more expensive than Kimi K2 Instruct ($0.50/1M tokens).

For output processing, Grok-4 ($15.00/1M tokens) is 30.0x more expensive than Kimi K2 Instruct ($0.50/1M tokens).

In conclusion, Grok-4 is more expensive than Kimi K2 Instruct.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Wed Jul 15 2026 • llm-stats.com
xAI
Grok-4
Input tokens$3.00
Output tokens$15.00
Best providerxAI
Moonshot AI
Kimi K2 Instruct
Input tokens$0.50
Output tokens$0.50
Best providerFireworks
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Grok-4 accepts 256,000 input tokens compared to Kimi K2 Instruct's 200,000 tokens. Kimi K2 Instruct can generate longer responses up to 200,000 tokens, while Grok-4 is limited to 8,000 tokens.

xAI
Grok-4
Input256,000 tokens
Output8,000 tokens
Moonshot AI
Kimi K2 Instruct
Input200,000 tokens
Output200,000 tokens
Wed Jul 15 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Grok-4 supports multimodal inputs, whereas Kimi K2 Instruct does not.

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

Grok-4

Text
Images
Audio
Video

Kimi K2 Instruct

Text
Images
Audio
Video

License

Usage and distribution terms

Grok-4 is licensed under a proprietary license, while Kimi K2 Instruct uses MIT.

License differences may affect how you can use these models in commercial or open-source projects.

Grok-4

Proprietary

Closed source

Kimi K2 Instruct

MIT

Open weights

Release Timeline

When each model was launched

Grok-4 was released on 2025-07-09, while Kimi K2 Instruct was released on 2025-07-11.

Kimi K2 Instruct is 0 month newer than Grok-4.

Grok-4

Jul 9, 2025

1.0 years ago

Kimi K2 Instruct

Jul 11, 2025

1.0 years ago

2d newer

Knowledge Cutoff

When training data ends

Grok-4 has a documented knowledge cutoff of 2024-12-31, while Kimi K2 Instruct's cutoff date is not specified.

We can confirm Grok-4's training data extends to 2024-12-31, but cannot make a direct comparison without Kimi K2 Instruct's cutoff date.

Grok-4

Dec 2024

Kimi K2 Instruct

—

Provider Availability

Grok-4 is available from xAI. Kimi K2 Instruct is available from Fireworks, Novita.

Grok-4

xai logo
xAI
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

Kimi K2 Instruct

fireworks logo
Fireworks
Input Price:Input: $0.50/1MOutput Price:Output: $0.50/1M
novita logo
Novita
Input Price:Input: $0.57/1MOutput Price:Output: $2.30/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

xAI
Larger context window (256,000 tokens)
Supports multimodal inputs
Higher AIME 2025 score (91.7% vs 49.5%)
Higher GPQA score (87.5% vs 75.1%)
Higher Humanity's Last Exam score (40.0% vs 4.7%)
Moonshot AI
Less expensive input tokens
Less expensive output tokens
Has open weights
xAIGrok-4
Moonshot AIKimi K2 Instruct
Compare in Playground

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok-4 and Kimi K2 Instruct side-by-side, then vote on the output you prefer.

Grok-4
✓ Preferred
Kimi K2 Instruct
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok-4
Moonshot AI
Kimi K2 Instruct

FAQ

Common questions about Grok-4 vs Kimi K2 Instruct.

Which is better, Grok-4 or Kimi K2 Instruct?

Grok-4 significantly outperforms across most benchmarks. Grok-4 is made by xAI and Kimi K2 Instruct is made by Moonshot AI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Grok-4 compare to Kimi K2 Instruct in benchmarks?

Grok-4 scores AIME 2025: 91.7%, HMMT25: 90.0%, GPQA: 87.5%, LiveCodeBench: 79.0%, Humanity's Last Exam: 40.0%. Kimi K2 Instruct scores MATH-500: 97.4%, GSM8k: 97.3%, CBNSL: 95.6%, HumanEval: 93.3%, MMLU-Redux: 92.7%.

Is Grok-4 cheaper than Kimi K2 Instruct?

Kimi K2 Instruct is 6.0x cheaper for input tokens. Grok-4 costs $3.00/M input and $15.00/M output via xai. Kimi K2 Instruct costs $0.50/M input and $0.50/M output via fireworks.

What are the context window sizes for Grok-4 and Kimi K2 Instruct?

Grok-4 supports 256K tokens and Kimi K2 Instruct 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-4 and Kimi K2 Instruct?

Key differences include context window (256K vs 200K), input pricing ($3.00 vs $0.50/M), multimodal support (yes vs no), licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok-4 and Kimi K2 Instruct?

Grok-4 is developed by xAI and Kimi K2 Instruct is developed by Moonshot AI.

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