# K-EXAONE 2.0 vs Mellum2.1-12B-A2.5B-Thinking

> Side-by-side benchmark comparison for K-EXAONE 2.0 and Mellum2.1-12B-A2.5B-Thinking across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/k-exaone-2-0-vs-mellum2-1-12b-a2-5b-thinking
- Last updated: October 8, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick Mellum2.1-12B-A2.5B-Thinking if you want the stronger benchmark profile. K-EXAONE 2.0 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Mellum2.1-12B-A2.5B-Thinking leads overall 37 to 0.
- The biggest single benchmark swing is Terminal-Bench 2.1 in Agentic, with scores of 43.8% and 17.4%.
- K-EXAONE 2.0 also has the larger context window at 262K.

## Model Snapshot

| Property | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking |
|----------|----------|----------|
| Creator | LG AI Research | JetBrains |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 262K | 128K |
| Overall Score | null | null |
| Benchmarks Covered | 15 | 7 |
| Pricing (input/output) | $0.00 / $0.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Not comparable
- K-EXAONE 2.0 public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 43.8% | 17.4% | K-EXAONE 2.0 |
| Claw-Eval | 77.7% | Coming soon | Coming soon |

### Coding

- Winner: Not comparable
- K-EXAONE 2.0 public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| SciCode | 37.4% | Coming soon | Coming soon |
| SWE-bench Verified | 68.2% | 47% | K-EXAONE 2.0 |
| Terminal-Bench 2.1 | 43.8% | Coming soon | Coming soon |
| LiveCodeBench v6 | Coming soon | 82.0% | Coming soon |
| SWE-bench Pro | Coming soon | 28% | Coming soon |

### Knowledge

- Winner: Not comparable
- K-EXAONE 2.0 public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Pro | 83.5% | Coming soon | Coming soon |
| GPQA-D | 82.2% | 64.6% | K-EXAONE 2.0 |
| HLE | 18.3% | Coming soon | Coming soon |
| MMMLU | 86.6% | Coming soon | Coming soon |
| MMLU-Redux | Coming soon | 87.8% | Coming soon |

### Multilingual

- Winner: Not comparable
- K-EXAONE 2.0 public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| PolyMath | 71.3% | Coming soon | Coming soon |

### Instruction Following

- Winner: Not comparable
- K-EXAONE 2.0 public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 92.4% | 90.6% | K-EXAONE 2.0 |
| IFBench | 72.6% | Coming soon | Coming soon |

### Mathematics

- Winner: Not comparable
- K-EXAONE 2.0 public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | K-EXAONE 2.0 | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | 92.3% | Coming soon | Coming soon |
| HMMT Feb 2026 | 78.4% | Coming soon | Coming soon |
| IMOAnswerBench | 78.6% | Coming soon | Coming soon |

## FAQ

### Which is better overall, K-EXAONE 2.0 or Mellum2.1-12B-A2.5B-Thinking?

Mellum2.1-12B-A2.5B-Thinking is ahead overall on BenchLM right now.

### How many benchmarks does K-EXAONE 2.0 cover on BenchLM?

K-EXAONE 2.0 currently has 15 sourced benchmark scores on BenchLM.

### How many benchmarks does Mellum2.1-12B-A2.5B-Thinking cover on BenchLM?

Mellum2.1-12B-A2.5B-Thinking currently has 7 sourced benchmark scores on BenchLM.

## Related Comparisons

- [K-EXAONE 2.0 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-k-exaone-2-0)
- [Mellum2.1-12B-A2.5B-Thinking vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mellum2-1-12b-a2-5b-thinking)
- [K-EXAONE 2.0 vs GPT-6 Astra](/compare/gpt-6-astra-vs-k-exaone-2-0)
- [Mellum2.1-12B-A2.5B-Thinking vs GPT-6 Astra](/compare/gpt-6-astra-vs-mellum2-1-12b-a2-5b-thinking)

## Explore More

- [K-EXAONE 2.0 profile](/models/k-exaone-2-0)
- [Mellum2.1-12B-A2.5B-Thinking profile](/models/mellum2-1-12b-a2-5b-thinking)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)