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 85. 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 79.2. The single biggest benchmark swing on the page is SWE-bench Pro, 83 to 74. Claude Opus 4.6 does hit back in multilingual, so the answer changes if that is the part of the workload you care about most.
Claude Opus 4.6 is also the more expensive model on tokens at $15.00 input / $75.00 output per 1M tokens, versus $1.75 input / $14.00 output per 1M tokens for GPT-5.3 Instant. That is roughly 5.4x on output cost alone. GPT-5.3 Instant is the reasoning model in the pair, while Claude Opus 4.6 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 Opus 4.6 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. Claude Opus 4.6 only becomes the better choice if multilingual is the priority or you need the larger 1M context window.
GPT-5.3 Instant
82.9
Claude Opus 4.6
79.2
GPT-5.3 Instant
78.7
Claude Opus 4.6
75.1
GPT-5.3 Instant
95
Claude Opus 4.6
94.6
GPT-5.3 Instant
94.2
Claude Opus 4.6
93.1
GPT-5.3 Instant
80.8
Claude Opus 4.6
78.9
GPT-5.3 Instant
96
Claude Opus 4.6
95
GPT-5.3 Instant
93.4
Claude Opus 4.6
94.7
GPT-5.3 Instant
97.2
Claude Opus 4.6
97.2
GPT-5.3 Instant is ahead overall, 87 to 85. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 83 and 74.
GPT-5.3 Instant has the edge for knowledge tasks in this comparison, averaging 80.8 versus 78.9. 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 75.1. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
GPT-5.3 Instant and Claude Opus 4.6 are effectively tied for math here, both landing at 97.2 on average.
GPT-5.3 Instant has the edge for reasoning in this comparison, averaging 94.2 versus 93.1. 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 79.2. 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 94.6. 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 95. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Claude Opus 4.6 has the edge for multilingual tasks in this comparison, averaging 94.7 versus 93.4. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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