Claude Sonnet 4.5 vs Grok 4.1 Fast
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
Grok 4.1 Fast by xAI wins on 9 of 14 benchmarks against Claude Sonnet 4.5 by Anthropic, which leads on 4. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.
Category-by-Category Breakdown
General Intelligence: In general intelligence, Grok 4.1 Fast scores 1482 on Chatbot Arena ELO compared to Claude Sonnet 4.5's 1380, while Grok 4.1 Fast scores 87.0% on MMLU-Pro compared to Claude Sonnet 4.5's 83.0%.
Coding: In coding, Claude Sonnet 4.5 scores 90.0% on HumanEval+ compared to Grok 4.1 Fast's 88.0%, while Claude Sonnet 4.5 scores 77.2% on SWE-bench Verified compared to Grok 4.1 Fast's 60.0%, while both score 62.0% on LiveCodeBench.
Math: In math, Grok 4.1 Fast scores 89.0% on MATH compared to Claude Sonnet 4.5's 87.0%, while Grok 4.1 Fast scores 96.0% on GSM8K compared to Claude Sonnet 4.5's 95.5%.
Reasoning: In reasoning, Claude Sonnet 4.5 scores 83.4% on GPQA Diamond compared to Grok 4.1 Fast's 72.0%, while Grok 4.1 Fast scores 48.0% on ARC-AGI compared to Claude Sonnet 4.5's 45.0%.
Context: In context, Claude Sonnet 4.5 scores 1.0M on Context Length compared to Grok 4.1 Fast's 256K.
Pricing Comparison
Claude Sonnet 4.5 costs $3.0/1M input tokens and $15.0/1M output tokens, while Grok 4.1 Fast costs $0.20/1M input and $0.50/1M output. Grok 4.1 Fast is the more affordable option for API usage.
Speed Comparison
Claude Sonnet 4.5 generates output at 67 tok/s compared to Grok 4.1 Fast's 120 tok/s, and the time to first token is 1170 ms for Claude Sonnet 4.5 versus 200 ms for Grok 4.1 Fast. Grok 4.1 Fast delivers faster throughput.
Verdict
For developers prioritizing coding, Claude Sonnet 4.5 has the edge. For those who value general intelligence and math and affordability and speed, Grok 4.1 Fast is the stronger choice.
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Claude Sonnet 4.5 vs Grok 4.1 Fast — FAQ
Which is better, Claude Sonnet 4.5 or Grok 4.1 Fast?
Grok 4.1 Fast wins on more benchmarks overall (9 vs 4). However, the best choice depends on your specific needs — each model excels in different areas.
How does Claude Sonnet 4.5 compare to Grok 4.1 Fast for coding?
Claude Sonnet 4.5 is better for coding, scoring 77.2% on SWE-bench Verified compared to 60.0%. SWE-bench tests real-world software engineering by resolving actual GitHub issues.
Is Claude Sonnet 4.5 cheaper than Grok 4.1 Fast?
Yes, Grok 4.1 Fast is cheaper. Claude Sonnet 4.5 costs $3.0/1M input and $15.0/1M output tokens. Grok 4.1 Fast costs $0.20/1M input and $0.50/1M output tokens.
Which is faster, Claude Sonnet 4.5 or Grok 4.1 Fast?
Grok 4.1 Fast is faster, generating output at 120 tok/s compared to 67 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the Claude Sonnet 4.5 vs Grok 4.1 Fast comparison cover?
This comparison covers 14 benchmarks including Chatbot Arena ELO, MMLU-Pro, HumanEval+, MATH, GPQA Diamond, SWE-bench Verified, Output Speed, LiveCodeBench, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.