Model comparison
Claude Sonnet 4.5 vs Grok Code Fast 1
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Sonnet 4.5 #96 (Estimated); Grok Code Fast 1 #180 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 4.5 and Grok Code Fast 1 share 1 comparable benchmark result. 1 of 8 categories are comparable. 11 results are unique to Claude Sonnet 4.5; 11 to Grok Code Fast 1.
Updated July 20, 2026- Shared results
- 1
- Claude Sonnet 4.5 only
- 11
- Grok Code Fast 1 only
- 11
- Comparable categories
- 1 / 8
Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if you want the cheaper token bill or you need the larger 256K context window.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Claude Sonnet 4.5 is clearly ahead on the BenchAlign aggregate, 53.61 to 38.64. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Sonnet 4.5's sharpest advantage is in coding, where it averages 77.2 against 70.8. The single biggest benchmark swing on the page is SWE-bench Verified, 77.2% to 70.8%.
Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.20 input / $1.50 output per 1M tokens for Grok Code Fast 1. That is roughly 10.0x on output cost alone. Grok Code Fast 1 gives you the larger context window at 256K, compared with 200K for Claude Sonnet 4.5.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude Sonnet 4.5 | Δ | Grok Code Fast 1 |
|---|---|---|---|
| Coding | Claude Sonnet 4.577.2 | Margin← 6.4 | Grok Code Fast 170.8 |
| Agentic | Claude Sonnet 4.555.4 | MarginNo overlap | Grok Code Fast 1Not measured |
| Reasoning | Claude Sonnet 4.513.6 | MarginNo overlap | Grok Code Fast 1Not measured |
| Knowledge | Claude Sonnet 4.583.4 | MarginNo overlap | Grok Code Fast 1Not measured |
| Math | Claude Sonnet 4.511.2 | MarginNo overlap | Grok Code Fast 1Not measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 77.2%B 70.8%Winner: Claude Sonnet 4.5Δ 6.4SWE-bench Verified: Claude Sonnet 4.5 scored 77.2%; Grok Code Fast 1 scored 70.8%. Claude Sonnet 4.5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Sonnet 4.5 | Grok Code Fast 1 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 4.5$3 input / $15 output | Grok Code Fast 1$0.2 input / $1.5 output | Grok Code Fast 1 has the lower combined listed price. |
| Generation speedtokens per second | Claude Sonnet 4.5Not available | Grok Code Fast 1172 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Sonnet 4.5Not available | Grok Code Fast 12.81 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Sonnet 4.5200K | Grok Code Fast 1256K | Grok Code Fast 1 lists the larger context window. |
Benchmark Deep Dive
Agentic6 benchmarks
CodingClaude Sonnet 4.5 wins2 benchmarks
Reasoning3 benchmarks
Knowledge7 benchmarks
| Benchmark | Claude Sonnet 4.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| GPQASource | 83.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 21.6% | Not comparable |
| AA-GPQA DiamondSource | — | 72.7% | Not comparable |
| AA-HLESource | — | 7.5% | Not comparable |
| AA-Omniscience IndexSource | — | -36.0% | Not comparable |
| AA-Omniscience AccuracySource | — | 23.8% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 78.5% | Not comparable |
Math3 benchmarks
Multimodal1 benchmarks
| Benchmark | Claude Sonnet 4.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| Design Arena WebsiteSource | 1222 | — | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Claude Sonnet 4.5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 41.4% | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude Sonnet 4.5 or Grok Code Fast 1?
Claude Sonnet 4.5 is ahead on BenchLM's BenchAlign leaderboard, 53.61 to 38.64. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 77.2% and 70.8%.
Which is better for coding, Claude Sonnet 4.5 or Grok Code Fast 1?
Claude Sonnet 4.5 has the edge for coding in this comparison, averaging 77.2 versus 70.8. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
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