Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
Mercury 2 is clearly ahead on the aggregate, 65 to 49. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Mercury 2's sharpest advantage is in coding, where it averages 41.1 against 19.3. The single biggest benchmark swing on the page is MuSR, 82 to 52. Claude 3 Haiku does hit back in multimodal & grounded, so the answer changes if that is the part of the workload you care about most.
Mercury 2 is the reasoning model in the pair, while Claude 3 Haiku 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 3 Haiku gives you the larger context window at 200K, compared with 128K for Mercury 2.
Pick Mercury 2 if you want the stronger benchmark profile. Claude 3 Haiku only becomes the better choice if multimodal & grounded is the priority or you need the larger 200K context window.
Mercury 2
63.7
Claude 3 Haiku
44
Mercury 2
41.1
Claude 3 Haiku
19.3
Mercury 2
68.3
Claude 3 Haiku
68.7
Mercury 2
80.1
Claude 3 Haiku
59.6
Mercury 2
57.2
Claude 3 Haiku
42.8
Mercury 2
84
Claude 3 Haiku
76
Mercury 2
79.7
Claude 3 Haiku
71.1
Mercury 2
80.9
Claude 3 Haiku
62.2
Mercury 2 is ahead overall, 65 to 49. The biggest single separator in this matchup is MuSR, where the scores are 82 and 52.
Mercury 2 has the edge for knowledge tasks in this comparison, averaging 57.2 versus 42.8. Inside this category, MMLU is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for coding in this comparison, averaging 41.1 versus 19.3. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for math in this comparison, averaging 80.9 versus 62.2. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for reasoning in this comparison, averaging 80.1 versus 59.6. Inside this category, MuSR is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for agentic tasks in this comparison, averaging 63.7 versus 44. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Claude 3 Haiku has the edge for multimodal and grounded tasks in this comparison, averaging 68.7 versus 68.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for instruction following in this comparison, averaging 84 versus 76. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Mercury 2 has the edge for multilingual tasks in this comparison, averaging 79.7 versus 71.1. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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