Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Sibling matchup inside the GPT-5.5 family.
GPT-5.5
89
GPT-5.5 Pro
100
Verified leaderboard positions: GPT-5.5 #2 · GPT-5.5 Pro unranked
GPT-5.5 makes more sense if knowledge is the priority or you want the cheaper token bill, while GPT-5.5 Pro is the cleaner fit if agentic is the priority.
Agentic
+8.3 difference
Knowledge
+9.2 difference
Math
+0.7 difference
GPT-5.5
GPT-5.5 Pro
$5 / $30
$30 / $180
N/A
N/A
N/A
N/A
1M
1M
GPT-5.5 makes more sense if knowledge is the priority or you want the cheaper token bill, while GPT-5.5 Pro is the cleaner fit if agentic is the priority.
GPT-5.5 and GPT-5.5 Pro sit in the same GPT-5.5 family. This page is less about two unrelated model lineages and more about how the siblings trade off on benchmark shape, token costs, and practical limits like context window.
GPT-5.5 Pro is clearly ahead on the provisional aggregate, 100 to 89. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.5 Pro's sharpest advantage is in agentic, where it averages 90.1 against 81.8. The single biggest benchmark swing on the page is BrowseComp, 84.4% to 90.1%. GPT-5.5 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $5.00 input / $30.00 output per 1M tokens for GPT-5.5. That is roughly 6.0x on output cost alone.
GPT-5.5 and GPT-5.5 Pro are sibling variants in the GPT-5.5 family, so the right pick depends on whether you value the better benchmark line, cheaper tokens, or the larger context window. GPT-5.5 Pro is ahead on BenchLM's provisional leaderboard 100 to 89.
GPT-5.5 has the edge for knowledge tasks in this comparison, averaging 66.4 versus 57.2. Inside this category, HLE is the benchmark that creates the most daylight between them.
GPT-5.5 Pro has the edge for math in this comparison, averaging 52.4 versus 51.7. Inside this category, FrontierMath is the benchmark that creates the most daylight between them.
GPT-5.5 Pro has the edge for agentic tasks in this comparison, averaging 90.1 versus 81.8. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.
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