Head-to-head comparison across 4benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Opus 4.5
80
Grok 4.20
78
Verified leaderboard positions: Claude Opus 4.5 #5 · Grok 4.20 unranked
Pick Claude Opus 4.5 if you want the stronger benchmark profile. Grok 4.20 only becomes the better choice if multimodal & grounded is the priority or you need the larger 2M context window.
Agentic
+15.4 difference
Coding
+4.9 difference
Reasoning
+11.1 difference
Multimodal
+4.6 difference
Claude Opus 4.5
Grok 4.20
$null / $null
$2 / $6
46 t/s
233 t/s
1.01s
10.33s
200K
2M
Pick Claude Opus 4.5 if you want the stronger benchmark profile. Grok 4.20 only becomes the better choice if multimodal & grounded is the priority or you need the larger 2M context window.
Claude Opus 4.5 has the cleaner provisional overall profile here, landing at 80 versus 78. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
Claude Opus 4.5's sharpest advantage is in agentic, where it averages 62.5 against 47.1. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 59.3% to 47.1%. Grok 4.20 does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.
Grok 4.20 is the reasoning model in the pair, while Claude Opus 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 Opus 4.5.
Claude Opus 4.5 is ahead on BenchLM's provisional leaderboard, 80 to 78. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 59.3% and 47.1%.
Claude Opus 4.5 has the edge for coding in this comparison, averaging 65.9 versus 61. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
Claude Opus 4.5 has the edge for reasoning in this comparison, averaging 64.4 versus 53.3. Grok 4.20 stays close enough that the answer can still flip depending on your workload.
Claude Opus 4.5 has the edge for agentic tasks in this comparison, averaging 62.5 versus 47.1. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Grok 4.20 has the edge for multimodal and grounded tasks in this comparison, averaging 75.2 versus 70.6. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
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