Claude 3.5 Haiku vs K2 Think V2
Wins 0 of 6 areas
—
Wins 4 of 6 areas
Coding · Reasoning · Long documents · Following instructions
K2 Think V2 is the stronger all-rounder.
Scores updated · 17 tests both models report · How we compare
Where each one wins
Tests won in each of the six areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software03K2 Think V23 of 3 tests
- ReasoningHard problems that need careful thinking02K2 Think V22 of 3 tests · 1 tie
- Long documentsFinding answers in very long texts01K2 Think V21 of 1 test
- Following instructionsDoing exactly what it is asked01K2 Think V21 of 1 test
- AgentsCarrying out multi-step tasks on its own00Even0 each · 2 ties
- FactsGetting facts right instead of making them up11Even1 each
Long documents and following instructions rest on a single test each.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where K2 Think V2 pulls ahead
- Graduate-level biology, physics and chemistry questionsGPQA Diamond+30.5points ahead
- Reasons across sets of long documentsAA-LCR+29.7points ahead
- Follows unfamiliar, precisely checkable instructionsIFBench+20points ahead
Where Claude 3.5 Haiku pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+30.1points ahead
Every test, side by side
All 17 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingK2 Think V2
- SciCodeK2 Think V2 by 5.627.433+5.6
- Terminal-Bench 2.1K2 Think V2 by 4.910.115+4.9
- Terminal-Bench HardK2 Think V2 by 4.52.36.8+4.5
ReasoningK2 Think V2
- GPQA DiamondK2 Think V2 by 30.540.871.3+30.5
- Humanity's Last ExamK2 Think V2 by 6.53.610.1+6.5
- CritPttie00tie
FactsEven
- AA-Omniscience · Non-hallucinationClaude 3.5 Haiku by 30.158.928.8+30.1
- AA-Omniscience · AccuracyK2 Think V2 by 4.813.218+4.8
Following instructionsK2 Think V2
- IFBenchK2 Think V2 by 2042.862.8+20
Other results5 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- AA-OmniscienceClaude 3.5 Haiku by 17.8-22.5-40.3+17.8
- Artificial Analysis Coding IndexK2 Think V2 by 5.115.921+5.1
- AA IntelligenceK2 Think V2 by 2.68.911.5+2.6
- τ²-Bench Telecom (AA run)tie24.625.4tie
- AA Agentic Indextie1.91.8tie
Questions people ask
Which is better, Claude 3.5 Haiku or K2 Think V2?
K2 Think V2 wins four of the six areas where both have results: coding, reasoning, long documents and following instructions. Claude 3.5 Haiku wins none. They are level on agents and facts.
Which is better for coding?
K2 Think V2. It wins 3 of the 3 coding tests both models report; Claude 3.5 Haiku wins none.
How do you compare the two?
We use the 17 benchmark tests both models have published scores on. The verdict counts the 12 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 5 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.