Model Comparison

Claude Opus 4.5 vs Grok-4

Both models are evenly matched across the benchmarks. Grok-4 is 1.7x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Opus 4.5 outperforms in 1 benchmarks (ARC-AGI v2), while Grok-4 is better at 1 benchmark (GPQA).

Both models are evenly matched across the benchmarks.

Wed Apr 22 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Grok-4 costs less

For input processing, Claude Opus 4.5 ($5.00/1M tokens) is 1.7x more expensive than Grok-4 ($3.00/1M tokens).

For output processing, Claude Opus 4.5 ($25.00/1M tokens) is 1.7x more expensive than Grok-4 ($15.00/1M tokens).

In conclusion, Claude Opus 4.5 is more expensive than Grok-4.*

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

Lowest available price from all providers
Wed Apr 22 2026 • llm-stats.com
Anthropic
Claude Opus 4.5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
xAI
Grok-4
Input tokens$3.00
Output tokens$15.00
Best providerxAI
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 Claude Opus 4.5's 200,000 tokens. Claude Opus 4.5 can generate longer responses up to 64,000 tokens, while Grok-4 is limited to 8,000 tokens.

Anthropic
Claude Opus 4.5
Input200,000 tokens
Output64,000 tokens
xAI
Grok-4
Input256,000 tokens
Output8,000 tokens
Wed Apr 22 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4.5 and Grok-4 support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Opus 4.5

Text
Images
Audio
Video

Grok-4

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.

Claude Opus 4.5

Proprietary

Closed source

Grok-4

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4.5 was released on 2025-11-24, while Grok-4 was released on 2025-07-09.

Claude Opus 4.5 is 5 months newer than Grok-4.

Claude Opus 4.5

Nov 24, 2025

4 months ago

4mo newer
Grok-4

Jul 9, 2025

9 months ago

Knowledge Cutoff

When training data ends

Claude Opus 4.5 has a knowledge cutoff of 2025-03-31, while Grok-4 has a cutoff of 2024-12-31.

Claude Opus 4.5 has more recent training data (up to 2025-03-31), making it potentially better informed about events through that date compared to Grok-4 (2024-12-31).

Claude Opus 4.5

Mar 2025

3 mo newer
Grok-4

Dec 2024

Provider Availability

Claude Opus 4.5 is available from Anthropic. Grok-4 is available from xAI.

Claude Opus 4.5

anthropic logo
Anthropic
Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M

Grok-4

xai logo
xAI
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Anthropic
Higher ARC-AGI v2 score (37.6% vs 15.9%)
xAI
Larger context window (256,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher GPQA score (87.5% vs 87.0%)
AnthropicClaude Opus 4.5
xAIGrok-4
Compare in Playground

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Opus 4.5
xAI
Grok-4

FAQ

Common questions about Claude Opus 4.5 vs Grok-4

Both models are evenly matched across the benchmarks. Claude Opus 4.5 is made by Anthropic and Grok-4 is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.
Claude Opus 4.5 scores Tau2 Telecom: 98.2%, MMMLU: 90.8%, Tau2 Retail: 88.9%, GPQA: 87.0%, SWE-Bench Verified: 80.9%. Grok-4 scores AIME 2025: 91.7%, HMMT25: 90.0%, GPQA: 87.5%, LiveCodeBench: 79.0%, Humanity's Last Exam: 40.0%.
Grok-4 is 1.7x cheaper for input tokens. Claude Opus 4.5 costs $5.00/M input and $25.00/M output via anthropic. Grok-4 costs $3.00/M input and $15.00/M output via xai.
Claude Opus 4.5 supports 200K tokens and Grok-4 supports 256K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.
Key differences include context window (200K vs 256K), input pricing ($5.00 vs $3.00/M). See the full comparison above for benchmark-by-benchmark results.
Claude Opus 4.5 is developed by Anthropic and Grok-4 is developed by xAI.