The AI arena is free today

Open Superagent

Claude Sonnet 5.5 vs Grok-2

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 11.4. Claude Sonnet 5.5 and Grok-2 cost the same.

Anthropic · xAI · Updated for 2026

Which is better?

Claude Sonnet 5.5 leads the overall LLM Stats Score 58.1 to 11.4, ranking #3 overall.

Claude Sonnet 5.5 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Sonnet 5.5

  • overall performance matters — it scores 58.1 and ranks #3 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you process long inputs — it offers a 1,000,000 token context window
  • you want the most recent training data — it shipped Sep 2026

Choose Grok-2

  • you want predictable pricing at $2.00/M input and $10.00/M output

At a glance

The differences that matter most.

Claude Sonnet 5.5
Anthropic
Grok-2
xAI
Core performance indexes
LLM Stats Score
58.1
#3
11.4
#265
Reasoning
56.6
#3
11.4
#262
Coding
48.9
#2
9.2
#181
Cost, coverage & limits
Benchmark wins
—
—
Input price
$2.00 / M
$2.00 / M
Output price
$10.00 / M
$10.00 / M
Context window
1,000,000
128,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

3 shared
Index
Claude Sonnet 5.5
Grok-2
Math
36.9#34
18.2#185
Vision
40.1#3
7.4#147
Multimodal
40.2#2
10.7#120
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

47 reported for Claude Sonnet 5.5 · 8 for Grok-2

No common benchmarks found

Claude Sonnet 5.5 and Grok-2don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

For input processing, Claude Sonnet 5.5 ($2.00/1M tokens) costs the same as Grok-2 ($2.00/1M tokens).

For output processing, Claude Sonnet 5.5 ($10.00/1M tokens) costs the same as Grok-2 ($10.00/1M tokens).

In conclusion, Claude Sonnet 5.5 and Grok-2 cost the same.*

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

Lowest available price from all providers
Tue Sep 29 2026 • llm-stats.com
Anthropic
Claude Sonnet 5.5
Input tokens$2.00
Output tokens$10.00
Best providerAnthropic
xAI
Grok-2
Input tokens$2.00
Output tokens$10.00
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Sonnet 5.5 accepts 1,000,000 input tokens compared to Grok-2's 128,000 tokens. Claude Sonnet 5.5 can generate longer responses up to 128,000 tokens, while Grok-2 is limited to 8,000 tokens.

Anthropic
Claude Sonnet 5.5
Input1,000,000 tokens
Output128,000 tokens
xAI
Grok-2
Input128,000 tokens
Output8,000 tokens
Tue Sep 29 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Sonnet 5.5 and Grok-2 support multimodal inputs.

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

Claude Sonnet 5.5

Text
Images
Audio
Video

Grok-2

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 Sonnet 5.5

Proprietary

Closed source

Grok-2

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 5.5 was released on 2026-09-28, while Grok-2 was released on 2024-08-13.

Claude Sonnet 5.5 is 26 months newer than Grok-2.

Claude Sonnet 5.5

Sep 28, 2026

1 days ago

2.1yr newer
Grok-2

Aug 13, 2024

2.1 years ago

Knowledge Cutoff

When training data ends

Claude Sonnet 5.5 has a documented knowledge cutoff of 2026-06-01, while Grok-2's cutoff date is not specified.

We can confirm Claude Sonnet 5.5's training data extends to 2026-06-01, but cannot make a direct comparison without Grok-2's cutoff date.

Claude Sonnet 5.5

Jun 2026

Grok-2

—

Provider Availability

Claude Sonnet 5.5 is available from Anthropic. Grok-2 is available from xAI.

Claude Sonnet 5.5

anthropic logo
Anthropic
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M

Grok-2

xai logo
xAI
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Sonnet 5.5 and Grok-2 side-by-side, then vote on the output you prefer.

Claude Sonnet 5.5
✓ Preferred
Grok-2
Open in Playground

FAQ

Common questions about Claude Sonnet 5.5 vs Grok-2.

Which is better, Claude Sonnet 5.5 or Grok-2?

Claude Sonnet 5.5 leads the LLM Stats Score 58.1 to 11.4. Claude Sonnet 5.5 is made by Anthropic and Grok-2 is made by xAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Sonnet 5.5 compare to Grok-2 in benchmarks?

Claude Sonnet 5.5 scores BenchCAD (with Python tool): 96.3%, ArXivMath (with tools): 95.2%, Global-MMLU: 92.1%, MILU: 91.6%, SWE-bench Multilingual: 90.3%. Grok-2 scores DocVQA: 93.6%, HumanEval: 88.4%, MMLU: 87.5%, MATH: 76.1%, MMLU-Pro: 75.5%.

Is Claude Sonnet 5.5 cheaper than Grok-2?

Both models cost $2.00 per million input tokens.

What are the context window sizes for Claude Sonnet 5.5 and Grok-2?

Claude Sonnet 5.5 supports 1.0M tokens and Grok-2 supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Sonnet 5.5 and Grok-2?

Key differences include LLM Stats Score (58.1 vs 11.4), context window (1.0M vs 128K). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 5.5 and Grok-2?

Claude Sonnet 5.5 is developed by Anthropic and Grok-2 is developed by xAI.

Related comparisons