Head-to-head comparison across 5benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
GPT-5.4 Pro
91
GPT-5.5
91
Verified leaderboard positions: GPT-5.4 Pro unranked · GPT-5.5 #5
Treat this as a split decision. GPT-5.4 Pro makes more sense if multimodal & grounded is the priority or you need the larger 1.05M context window; GPT-5.5 is the better fit if knowledge is the priority or you want the cheaper token bill.
Agentic
+7.8 difference
Reasoning
+1.7 difference
Knowledge
+17.4 difference
Math
+1.7 difference
Multimodal
+23.6 difference
GPT-5.4 Pro
GPT-5.5
$30 / $180
$5 / $30
74 t/s
N/A
151.79s
N/A
1.05M
1M
Treat this as a split decision. GPT-5.4 Pro makes more sense if multimodal & grounded is the priority or you need the larger 1.05M context window; GPT-5.5 is the better fit if knowledge is the priority or you want the cheaper token bill.
GPT-5.4 Pro and GPT-5.5 finish on the same provisional overall score, so this is less about a single winner and more about where the edge shows up. The provisional headline says tie; the benchmark table is where the real choice happens.
GPT-5.4 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-5.4 Pro gives you the larger context window at 1.05M, compared with 1M for GPT-5.5.
GPT-5.4 Pro and GPT-5.5 are tied on the provisional overall score, so the right pick depends on which category matters most for your use case.
GPT-5.5 has the edge for knowledge tasks in this comparison, averaging 66.4 versus 49. Inside this category, HLE is the benchmark that creates the most daylight between them.
GPT-5.5 has the edge for math in this comparison, averaging 51.7 versus 50. Inside this category, FrontierMath is the benchmark that creates the most daylight between them.
GPT-5.5 has the edge for reasoning in this comparison, averaging 85 versus 83.3. Inside this category, CritPt is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for agentic tasks in this comparison, averaging 89.3 versus 81.5. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.
GPT-5.4 Pro has the edge for multimodal and grounded tasks in this comparison, averaging 94 versus 70.4. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
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