Head-to-head comparison across 4benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Opus 4.6
88
GPT-5.5
89
Verified leaderboard positions: Claude Opus 4.6 #3 · GPT-5.5 #2
Pick GPT-5.5 if you want the stronger benchmark profile. Claude Opus 4.6 only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Agentic
+9.2 difference
Coding
+5.8 difference
Knowledge
+9.8 difference
Multimodal
+8.3 difference
Claude Opus 4.6
GPT-5.5
$5 / $25
$5 / $30
40 t/s
N/A
1.78s
N/A
1M
1M
Pick GPT-5.5 if you want the stronger benchmark profile. Claude Opus 4.6 only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
GPT-5.5 finishes one point ahead on BenchLM's provisional leaderboard, 89 to 88. That is enough to call, but not enough to treat as a blowout. This matchup comes down to a few meaningful edges rather than one model dominating the board.
GPT-5.5's sharpest advantage is in agentic, where it averages 81.8 against 72.6. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 65.4% to 82.7%. Claude Opus 4.6 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $5.00 input / $25.00 output per 1M tokens for Claude Opus 4.6. GPT-5.5 is the reasoning model in the pair, while Claude Opus 4.6 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-5.5 is ahead on BenchLM's provisional leaderboard, 89 to 88. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 65.4% and 82.7%.
Claude Opus 4.6 has the edge for knowledge tasks in this comparison, averaging 76.2 versus 66.4. Inside this category, GPQA-D is the benchmark that creates the most daylight between them.
Claude Opus 4.6 has the edge for coding in this comparison, averaging 64.4 versus 58.6. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
GPT-5.5 has the edge for agentic tasks in this comparison, averaging 81.8 versus 72.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Claude Opus 4.6 has the edge for multimodal and grounded tasks in this comparison, averaging 77.3 versus 69. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
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