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 62. 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 41.7. The single biggest benchmark swing on the page is LiveCodeBench, 75 to 36.
GPT-5.3 Instant is also the more expensive model on tokens at $1.75 input / $14.00 output per 1M tokens, versus $0.80 input / $4.00 output per 1M tokens for Claude Haiku 4.5. That is roughly 3.5x on output cost alone. GPT-5.3 Instant is the reasoning model in the pair, while Claude Haiku 4.5 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. Claude Haiku 4.5 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. Claude Haiku 4.5 only becomes the better choice if you want the cheaper token bill or you need the larger 200K context window.
GPT-5.3 Instant
82.9
Claude Haiku 4.5
56.7
GPT-5.3 Instant
78.7
Claude Haiku 4.5
41.7
GPT-5.3 Instant
95
Claude Haiku 4.5
78.4
GPT-5.3 Instant
94.2
Claude Haiku 4.5
68.9
GPT-5.3 Instant
80.8
Claude Haiku 4.5
53.6
GPT-5.3 Instant
96
Claude Haiku 4.5
86
GPT-5.3 Instant
93.4
Claude Haiku 4.5
80.1
GPT-5.3 Instant
97.2
Claude Haiku 4.5
73.3
GPT-5.3 Instant is ahead overall, 87 to 62. The biggest single separator in this matchup is LiveCodeBench, where the scores are 75 and 36.
GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 53.6. 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 41.7. 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 73.3. 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 68.9. Inside this category, SimpleQA 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 56.7. 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 78.4. Inside this category, OfficeQA 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 86. 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 80.1. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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