Claude Sonnet 4.5 vs Grok Code Fast 1
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Claude Sonnet 4.5
65.5Anthropic · Sep 2025
The model that made 30-hour autonomous coding sessions real — 77.2% SWE-bench Verified and a 1M-token context beta at $3/$15.
Grok Code Fast 1
xAI · Aug 2025
A speed-first coding model built for agentic IDE loops, popular as a cheap fast tier in Cursor and similar tools.
The verdict
Claude Sonnet 4.5 wins 1 of the 1 benchmarks these models share, against 0 for Grok Code Fast 1. On price the gap is dramatic: Grok Code Fast 1 works out roughly 11x cheaper per blended million tokens. Grok Code Fast 1 also takes 256K of context versus 200K for Claude Sonnet 4.5.
Benchmark head-to-head 1–0
Specs & pricing
| Claude Sonnet 4.5 | Grok Code Fast 1 | |
|---|---|---|
| modhub Index | 65.5 | — |
| Input price / 1M | $3 | $0.2 |
| Output price / 1M | $15 | $1.5 |
| Context window | 200K | 256K |
| Max output | 64K | — |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text |
| Knowledge cutoff | Jan 2025 | Aug 2025 |
| Released | Sep 2025 | Aug 2025 |
| Example monthly cost* | $52.50 | $4.25 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, Claude Sonnet 4.5 or Grok Code Fast 1?
- Claude Sonnet 4.5 wins 1 of the 1 benchmarks these models share, against 0 for Grok Code Fast 1. On price the gap is dramatic: Grok Code Fast 1 works out roughly 11x cheaper per blended million tokens. Grok Code Fast 1 also takes 256K of context versus 200K for Claude Sonnet 4.5.
- Which is cheaper, Claude Sonnet 4.5 or Grok Code Fast 1?
- Claude Sonnet 4.5 costs $3/$15 per million input/output tokens, while Grok Code Fast 1 costs $0.2/$1.5. For a typical workload of 10M input and 1.5M output tokens per month, that's $52.50 versus $4.25.
- Which model is better for coding, Claude Sonnet 4.5 or Grok Code Fast 1?
- On SWE-bench Verified — the standard agentic-coding benchmark — Claude Sonnet 4.5 scores 77.2% versus 70.8% for Grok Code Fast 1, making Claude Sonnet 4.5 the stronger pick for coding agents.
More comparisons
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