Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
GPT-5.3 Instant has the cleaner overall profile here, landing at 87 versus 84. It is a real lead, but still close enough that category-level strengths matter more than the headline number.
GPT-5.3 Instant's sharpest advantage is in agentic, where it averages 82.9 against 76.1. The single biggest benchmark swing on the page is OSWorld-Verified, 80 to 68. Gemini 3.1 Pro does hit back in multilingual, so the answer changes if that is the part of the workload you care about most.
GPT-5.3 Instant is also the more expensive model on tokens at $1.75 input / $14.00 output per 1M tokens, versus $1.25 input / $5.00 output per 1M tokens for Gemini 3.1 Pro. That is roughly 2.8x on output cost alone. GPT-5.3 Instant is the reasoning model in the pair, while Gemini 3.1 Pro 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. Gemini 3.1 Pro gives you the larger context window at 1M, compared with 128K for GPT-5.3 Instant.
Pick GPT-5.3 Instant if you want the stronger benchmark profile. Gemini 3.1 Pro only becomes the better choice if multilingual is the priority or you want the cheaper token bill.
GPT-5.3 Instant
82.9
Gemini 3.1 Pro
76.1
GPT-5.3 Instant
78.7
Gemini 3.1 Pro
71.9
GPT-5.3 Instant
95
Gemini 3.1 Pro
95
GPT-5.3 Instant
94.2
Gemini 3.1 Pro
92.7
GPT-5.3 Instant
80.8
Gemini 3.1 Pro
79.4
GPT-5.3 Instant
96
Gemini 3.1 Pro
95
GPT-5.3 Instant
93.4
Gemini 3.1 Pro
94.1
GPT-5.3 Instant
97.2
Gemini 3.1 Pro
96.8
GPT-5.3 Instant is ahead overall, 87 to 84. The biggest single separator in this matchup is OSWorld-Verified, where the scores are 80 and 68.
GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 79.4. Inside this category, HLE is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for coding in this comparison, averaging 78.7 versus 71.9. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for math in this comparison, averaging 97.2 versus 96.8. Inside this category, MATH-500 is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for reasoning in this comparison, averaging 94.2 versus 92.7. Inside this category, BBH is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for agentic tasks in this comparison, averaging 82.9 versus 76.1. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.
GPT-5.3 Instant and Gemini 3.1 Pro are effectively tied for multimodal and grounded tasks here, both landing at 95 on average.
GPT-5.3 Instant has the edge for instruction following in this comparison, averaging 96 versus 95. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Gemini 3.1 Pro has the edge for multilingual tasks in this comparison, averaging 94.1 versus 93.4. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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