Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
GPT-5.3 Instant is clearly ahead on the aggregate, 87 to 70. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.3 Instant's sharpest advantage is in coding, where it averages 78.7 against 49.1. The single biggest benchmark swing on the page is LiveCodeBench, 75 to 40.
o3 is also the more expensive model on tokens at $10.00 input / $40.00 output per 1M tokens, versus $1.75 input / $14.00 output per 1M tokens for GPT-5.3 Instant. That is roughly 2.9x on output cost alone. o3 gives you the larger context window at 200K, compared with 128K for GPT-5.3 Instant.
Pick GPT-5.3 Instant if you want the stronger benchmark profile. o3 only becomes the better choice if you need the larger 200K context window.
GPT-5.3 Instant
82.9
o3
69.9
GPT-5.3 Instant
78.7
o3
49.1
GPT-5.3 Instant
95
o3
72.3
GPT-5.3 Instant
94.2
o3
82.6
GPT-5.3 Instant
80.8
o3
66
GPT-5.3 Instant
96
o3
85
GPT-5.3 Instant
93.4
o3
81.1
GPT-5.3 Instant
97.2
o3
87.5
GPT-5.3 Instant is ahead overall, 87 to 70. The biggest single separator in this matchup is LiveCodeBench, where the scores are 75 and 40.
GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 66. 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 49.1. Inside this category, LiveCodeBench 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 87.5. Inside this category, AIME 2023 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 82.6. Inside this category, MRCRv2 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 69.9. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for multimodal and grounded tasks in this comparison, averaging 95 versus 72.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for instruction following in this comparison, averaging 96 versus 85. Inside this category, IFEval is the benchmark that creates the most daylight between them.
GPT-5.3 Instant has the edge for multilingual tasks in this comparison, averaging 93.4 versus 81.1. Inside this category, MGSM is the benchmark that creates the most daylight between them.
Get notified when new models drop, benchmark scores change, or the leaderboard shifts. One email per week.
Free. No spam. Unsubscribe anytime. We only store derived location metadata for consent routing.