Side-by-side benchmark comparison across knowledge, coding, math, and reasoning.
GPT-5.1 is clearly ahead on the aggregate, 85 to 51. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.1's sharpest advantage is in coding, where it averages 72.7 against 41. The single biggest benchmark swing on the page is SWE-bench Verified, 68 to 41. o1 does hit back in instruction following, so the answer changes if that is the part of the workload you care about most.
o1 is also the more expensive model on tokens at $15.00 input / $60.00 output per 1M tokens, versus $1.50 input / $6.00 output per 1M tokens for GPT-5.1. That is roughly 10.0x on output cost alone.
Pick GPT-5.1 if you want the stronger benchmark profile. o1 only becomes the better choice if instruction following is the priority.
GPT-5.1
81
o1
83.8
GPT-5.1
72.7
o1
41
GPT-5.1
96.8
o1
74.3
GPT-5.1
89
o1
92.2
GPT-5.1 is ahead overall, 85 to 51. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 68 and 41.
o1 has the edge for knowledge tasks in this comparison, averaging 83.8 versus 81. Inside this category, GPQA is the benchmark that creates the most daylight between them.
GPT-5.1 has the edge for coding in this comparison, averaging 72.7 versus 41. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
GPT-5.1 has the edge for math in this comparison, averaging 96.8 versus 74.3. Inside this category, AIME 2024 is the benchmark that creates the most daylight between them.
o1 has the edge for instruction following in this comparison, averaging 92.2 versus 89. Inside this category, IFEval is the benchmark that creates the most daylight between them.
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