Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude 4 Sonnet
52
GPT-5.3 Codex
89
Pick GPT-5.3 Codex if you want the stronger benchmark profile. Claude 4 Sonnet 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.
Coding
+9.6 difference
Claude 4 Sonnet
GPT-5.3 Codex
$null / $null
$2.5 / $10
40 t/s
79 t/s
1.33s
88.26s
200K
400K
Pick GPT-5.3 Codex if you want the stronger benchmark profile. Claude 4 Sonnet 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.
GPT-5.3 Codex is clearly ahead on the provisional aggregate, 89 to 52. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.3 Codex is the reasoning model in the pair, while Claude 4 Sonnet 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. GPT-5.3 Codex gives you the larger context window at 400K, compared with 200K for Claude 4 Sonnet.
GPT-5.3 Codex is ahead on BenchLM's provisional leaderboard, 89 to 52. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 72.7% and 85%.
Claude 4 Sonnet has the edge for coding in this comparison, averaging 72.7 versus 63.1. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
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