Model comparison
Claude Sonnet 4.5 vs Grok 4.20
Head-to-head evidence from 5 shared benchmark results across 4 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Sonnet 4.5 #98 (Estimated); Grok 4.20 #93 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 4.5 and Grok 4.20 share 5 comparable benchmark results. 3 of 8 categories are comparable. 7 results are unique to Claude Sonnet 4.5; 14 to Grok 4.20.
Updated July 28, 2026- Shared results
- 5
- Claude Sonnet 4.5 only
- 7
- Grok 4.20 only
- 14
- Comparable categories
- 3 / 8
Pick Grok 4.20 if you want the stronger benchmark profile. Claude Sonnet 4.5 only becomes the better choice if coding is the priority or you would rather avoid the extra latency and token burn of a reasoning model.
Confidence note. This is a partial-evidence comparison with 5 shared benchmark results across 4 evidence categories; 3 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Grok 4.20 has the cleaner BenchAlign overall profile here, landing at 53.88 versus 52.82. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
Grok 4.20's sharpest advantage is in reasoning, where it averages 53.3 against 13.6. The single biggest benchmark swing on the page is ARC-AGI-2, 13.6% to 53.3%. Claude Sonnet 4.5 does hit back in coding, so the answer changes if that is the part of the workload you care about most.
Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $2.00 input / $6.00 output per 1M tokens for Grok 4.20. That is roughly 2.5x on output cost alone. Grok 4.20 is the reasoning model in the pair, while Claude Sonnet 4.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Grok 4.20 gives you the larger context window at 2M, 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 4.20 |
|---|---|---|---|
| Reasoning | Claude Sonnet 4.513.6 | Margin→ 39.7 | Grok 4.2053.3 |
| Coding | Claude Sonnet 4.577.2 | Margin← 10.1 | Grok 4.2067.1 |
| Agentic | Claude Sonnet 4.555.4 | Margin← 8.3 | Grok 4.2047.1 |
| Knowledge | Claude Sonnet 4.583.4 | MarginNo overlap | Grok 4.20Not measured |
| Math | Claude Sonnet 4.511.2 | MarginNo overlap | Grok 4.20Not measured |
| Multimodal | Claude Sonnet 4.5Not measured | MarginNo overlap | Grok 4.2070.1 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
ARC-AGI-2
ReasoningA 13.6%B 53.3%Winner: Grok 4.20Δ 39.7ARC-AGI-2: Claude Sonnet 4.5 scored 13.6%; Grok 4.20 scored 53.3%. Grok 4.20 wins this benchmark. - Source ↗
Terminal-Bench 2.0
AgenticA 50%B 47.1%Winner: Claude Sonnet 4.5Δ 2.9Terminal-Bench 2.0: Claude Sonnet 4.5 scored 50%; Grok 4.20 scored 47.1%. Claude Sonnet 4.5 wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 77.2%B 76.7%Winner: Claude Sonnet 4.5Δ 0.5SWE-bench Verified: Claude Sonnet 4.5 scored 77.2%; Grok 4.20 scored 76.7%. 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 4.20 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 4.5$3 input / $15 output | Grok 4.20$2 input / $6 output | Grok 4.20 has the lower combined listed price. |
| Generation speedtokens per second | Claude Sonnet 4.5Not available | Grok 4.20233 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Sonnet 4.5Not available | Grok 4.2010.33 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Sonnet 4.5200K | Grok 4.202M | Grok 4.20 lists the larger context window. |
Benchmark Deep Dive
AgenticClaude Sonnet 4.5 wins6 benchmarks
| Benchmark | Claude Sonnet 4.5 | Grok 4.20 | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 50% | 47.1% | Claude Sonnet 4.5 leads |
| OSWorld-VerifiedSource | 61.4% | — | Not comparable |
| VITA-BenchSource | 17.0% | — | Not comparable |
| Gert LabsSource | 48.51% | 38.36% | Claude Sonnet 4.5 leads |
| JobBenchSource | 27.7% | — | Not comparable |
| DeepSearchQASource | — | 62.8% | Not comparable |
CodingClaude Sonnet 4.5 wins4 benchmarks
ReasoningGrok 4.20 wins2 benchmarks
Knowledge5 benchmarks
Math3 benchmarks
Frequently Asked Questions (4)
Which is better, Claude Sonnet 4.5 or Grok 4.20?
Grok 4.20 is ahead on BenchLM's BenchAlign leaderboard, 53.88 to 52.82. The biggest single separator in this matchup is ARC-AGI-2, where the scores are 13.6% and 53.3%.
Which is better for coding, Claude Sonnet 4.5 or Grok 4.20?
Claude Sonnet 4.5 has the edge for coding in this comparison, averaging 77.2 versus 67.1. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
Which is better for reasoning, Claude Sonnet 4.5 or Grok 4.20?
Grok 4.20 has the edge for reasoning in this comparison, averaging 53.3 versus 13.6. Inside this category, ARC-AGI-2 is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Claude Sonnet 4.5 or Grok 4.20?
Claude Sonnet 4.5 has the edge for agentic tasks in this comparison, averaging 55.4 versus 47.1. Inside this category, Gert Labs is the benchmark that creates the most daylight between them.
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