Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
Claude Sonnet 4.5 is clearly ahead on the aggregate, 76 to 65. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Sonnet 4.5's sharpest advantage is in mathematics, where it averages 92.4 against 75.9. The single biggest benchmark swing on the page is AIME 2023, 97 to 72.
Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.25 input / $2.00 output per 1M tokens for Seed 1.6. That is roughly 7.5x on output cost alone. Seed 1.6 is the reasoning model in the pair, while Claude Sonnet 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. Seed 1.6 gives you the larger context window at 256K, compared with 200K for Claude Sonnet 4.5.
Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. Seed 1.6 only becomes the better choice if you want the cheaper token bill or you need the larger 256K context window.
Claude Sonnet 4.5
70.3
Seed 1.6
62.3
Claude Sonnet 4.5
57.5
Seed 1.6
42.4
Claude Sonnet 4.5
91.4
Seed 1.6
79.6
Claude Sonnet 4.5
86
Seed 1.6
74.5
Claude Sonnet 4.5
70.7
Seed 1.6
56.4
Claude Sonnet 4.5
90
Seed 1.6
87
Claude Sonnet 4.5
88.4
Seed 1.6
83.4
Claude Sonnet 4.5
92.4
Seed 1.6
75.9
Claude Sonnet 4.5 is ahead overall, 76 to 65. The biggest single separator in this matchup is AIME 2023, where the scores are 97 and 72.
Claude Sonnet 4.5 has the edge for knowledge tasks in this comparison, averaging 70.7 versus 56.4. Inside this category, MMLU is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for coding in this comparison, averaging 57.5 versus 42.4. Inside this category, HumanEval is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for math in this comparison, averaging 92.4 versus 75.9. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for reasoning in this comparison, averaging 86 versus 74.5. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for agentic tasks in this comparison, averaging 70.3 versus 62.3. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for multimodal and grounded tasks in this comparison, averaging 91.4 versus 79.6. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for instruction following in this comparison, averaging 90 versus 87. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Claude Sonnet 4.5 has the edge for multilingual tasks in this comparison, averaging 88.4 versus 83.4. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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