Claude Opus 5.5 vs Grok Code Fast 1
Claude Opus 5.5 leads the LLM Stats Score 59.7 to 20.7. Grok Code Fast 1 is 15.2x cheaper per token.
Anthropic · xAI · Updated for 2026
Which is better?
Claude Opus 5.5 leads the overall LLM Stats Score 59.7 to 20.7, ranking #1 overall.
On price, Grok Code Fast 1 is roughly 15.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Claude Opus 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 Opus 5.5
- overall performance matters — it scores 59.7 and ranks #1 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 Code Fast 1
- cost matters — it's about 15.2x cheaper per token
At a glance
The differences that matter most.
Individual benchmarks
31 reported for Claude Opus 5.5 · 1 for Grok Code Fast 1
Claude Opus 5.5 and Grok Code Fast 1don'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 Opus 5.5 ($4.00/1M tokens) is 20.0x more expensive than Grok Code Fast 1 ($0.20/1M tokens).
For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 13.3x more expensive than Grok Code Fast 1 ($1.50/1M tokens).
In conclusion, Claude Opus 5.5 is more expensive than Grok Code Fast 1.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Opus 5.5 accepts 1,000,000 input tokens compared to Grok Code Fast 1's 256,000 tokens. Claude Opus 5.5 can generate longer responses up to 128,000 tokens, while Grok Code Fast 1 is limited to 10,000 tokens.
Input capabilities
Documented input modalities across available providers
Claude Opus 5.5 supports multimodal inputs, whereas Grok Code Fast 1 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
Grok Code Fast 1
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Opus 5.5 was released on 2026-09-22, while Grok Code Fast 1 was released on 2025-08-28.
Claude Opus 5.5 is 13 months newer than Grok Code Fast 1.
Sep 22, 2026
0 days ago
1.1yr newerAug 28, 2025
1.1 years ago
Knowledge Cutoff
When training data ends
Claude Opus 5.5 has a documented knowledge cutoff of 2026-06-01, while Grok Code Fast 1'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 Code Fast 1's cutoff date.
Jun 2026
—
Provider Availability
Claude Opus 5.5 is available from Anthropic. Grok Code Fast 1 is available from xAI.
Claude Opus 5.5
Grok Code Fast 1
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Opus 5.5 and Grok Code Fast 1 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Opus 5.5 vs Grok Code Fast 1.