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Claude Opus 5.5 vs Grok 4.3

Claude Opus 5.5 leads the LLM Stats Score 60.4 to 22.0. Grok 4.3 is 5.1x cheaper per token.

Anthropic · xAI · Updated for 2026

Which is better?

Claude Opus 5.5 leads the overall LLM Stats Score 60.4 to 22.0, ranking #1 overall.

On price, Grok 4.3 is roughly 5.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

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

Choose Claude Opus 5.5

  • overall performance matters — it scores 60.4 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and agents — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

Choose Grok 4.3

  • cost matters — it's about 5.1x cheaper per token

At a glance

The differences that matter most.

Claude Opus 5.5
Anthropic
Grok 4.3
xAI
Core performance indexes
LLM Stats Score
60.4
#1
22.0
#202
Reasoning
59.5
#1
22.5
#193
Agents
45.5
#1
10.1
#141
Cost, coverage & limits
Benchmark wins
—
—
Input price
$4.00 / M
$1.25 / M
Output price
$20.00 / M
$2.50 / M
Context window
1,000,000
1,000,000

Individual benchmarks

31 reported for Claude Opus 5.5 · 1 for Grok 4.3

No common benchmarks found

Claude Opus 5.5 and Grok 4.3don'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

Grok 4.3 costs less

For input processing, Claude Opus 5.5 ($4.00/1M tokens) is 3.2x more expensive than Grok 4.3 ($1.25/1M tokens).

For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 8.0x more expensive than Grok 4.3 ($2.50/1M tokens).

In conclusion, Claude Opus 5.5 is more expensive than Grok 4.3.*

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

Lowest available price from all providers
Sun Oct 25 2026 • llm-stats.com
Anthropic
Claude Opus 5.5
Input tokens$4.00
Output tokens$20.00
Best providerAnthropic
xAI
Grok 4.3
Input tokens$1.25
Output tokens$2.50
Best providerxAI
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Both models have the same input context window of 1,000,000 tokens. Only Claude Opus 5.5 specifies output context (128,000 tokens).

Anthropic
Claude Opus 5.5
Input1,000,000 tokens
Output128,000 tokens
xAI
Grok 4.3
Input1,000,000 tokens
Output- tokens
Sun Oct 25 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Opus 5.5 supports multimodal inputs, whereas Grok 4.3 does not.

Claude Opus 5.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 5.5

Text
Images
Audio
Video

Grok 4.3

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 5.5

Proprietary

Closed source

Grok 4.3

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 5.5 was released on 2026-09-22, while Grok 4.3 was released on 2026-05-06.

Claude Opus 5.5 is 5 months newer than Grok 4.3.

Claude Opus 5.5

Sep 22, 2026

1 months ago

4mo newer
Grok 4.3

May 6, 2026

5 months ago

Knowledge Cutoff

When training data ends

Claude Opus 5.5 has a documented knowledge cutoff of 2026-06-01, while Grok 4.3's cutoff date is not specified.

We can confirm Claude Opus 5.5's training data extends to 2026-06-01, but cannot make a direct comparison without Grok 4.3's cutoff date.

Claude Opus 5.5

Jun 2026

Grok 4.3

—

Provider Availability

Claude Opus 5.5 is available from Anthropic. Grok 4.3 is available from xAI.

Claude Opus 5.5

anthropic logo
Anthropic
Input Price:Input: $4.00/1MOutput Price:Output: $20.00/1M

Grok 4.3

xai logo
xAI
Input Price:Input: $1.25/1MOutput Price:Output: $2.50/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Opus 5.5 and Grok 4.3 side-by-side, then vote on the output you prefer.

Claude Opus 5.5
✓ Preferred
Grok 4.3
Open in Playground

FAQ

Common questions about Claude Opus 5.5 vs Grok 4.3.

Which is better, Claude Opus 5.5 or Grok 4.3?

Claude Opus 5.5 leads the LLM Stats Score 60.4 to 22.0. Claude Opus 5.5 is made by Anthropic and Grok 4.3 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 Opus 5.5 compare to Grok 4.3 in benchmarks?

Claude Opus 5.5 scores BenchCAD (with Python tool): 96.2%, Global-MMLU: 94.3%, SWE-bench Multilingual: 93.9%, MILU: 93.1%, ArXivMath: 91.2%. Grok 4.3 scores Finance Agent v2: 37.7%.

Is Claude Opus 5.5 cheaper than Grok 4.3?

Grok 4.3 is 3.2x cheaper for input tokens. Claude Opus 5.5 costs $4.00/M input and $20.00/M output via anthropic. Grok 4.3 costs $1.25/M input and $2.50/M output via xai.

What are the context window sizes for Claude Opus 5.5 and Grok 4.3?

Claude Opus 5.5 supports 1.0M tokens and Grok 4.3 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 5.5 and Grok 4.3?

Key differences include LLM Stats Score (60.4 vs 22.0), input pricing ($4.00 vs $1.25/M), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 5.5 and Grok 4.3?

Claude Opus 5.5 is developed by Anthropic and Grok 4.3 is developed by xAI.

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