Claude Opus 4.1 vs Grok 4 Fast
Claude Opus 4.1 and Grok 4 Fast are closely matched at 30.0 and 32.0 on the LLM Stats Score. Grok 4 Fast is 109.1x cheaper per token.
Anthropic · xAI · Updated for 2026
Which is better?
Claude Opus 4.1 and Grok 4 Fast are closely matched on the overall LLM Stats Score at 30.0 and 32.0.
In the 2 individual benchmarks reported for both models, Grok 4 Fast wins 2; this is a narrower head-to-head signal than the composite indexes.
On price, Grok 4 Fast is roughly 109.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Grok 4 Fast also accepts a larger context window (2,000,000 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 4.1
- you want predictable pricing at $15.00/M input and $75.00/M output
Choose Grok 4 Fast
- you value its reported benchmark strengths — it wins 2 of 2 exact shared results
- cost matters — it's about 109.1x cheaper per token
- you process long inputs — it offers a 2,000,000 token context window
- you want the most recent training data — it shipped Aug 2025
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
8 reported for Claude Opus 4.1 · 7 for Grok 4 Fast
Claude Opus 4.1 outperforms in 0 benchmarks, while Grok 4 Fast is better at 2 benchmarks (AIME 2025, GPQA).
Grok 4 Fast significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Opus 4.1 ($15.00/1M tokens) is 75.0x more expensive than Grok 4 Fast ($0.20/1M tokens).
For output processing, Claude Opus 4.1 ($75.00/1M tokens) is 150.0x more expensive than Grok 4 Fast ($0.50/1M tokens).
In conclusion, Claude Opus 4.1 is more expensive than Grok 4 Fast.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok 4 Fast accepts 2,000,000 input tokens compared to Claude Opus 4.1's 200,000 tokens. Claude Opus 4.1 can generate longer responses up to 32,000 tokens, while Grok 4 Fast is limited to 30,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Claude Opus 4.1 and Grok 4 Fast support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Opus 4.1
Grok 4 Fast
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 4.1 was released on 2025-08-05, while Grok 4 Fast was released on 2025-08-28.
Grok 4 Fast is 1 month newer than Claude Opus 4.1.
Aug 5, 2025
1.1 years ago
Aug 28, 2025
1.0 years ago
3w newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Claude Opus 4.1 is available from Anthropic, Bedrock, Google. Grok 4 Fast is available from xAI.
Claude Opus 4.1
Grok 4 Fast
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Opus 4.1 and Grok 4 Fast side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Opus 4.1 vs Grok 4 Fast.