# Mellum2.1-12B-A2.5B-Thinking vs Phi-4-reasoning-plus

> Side-by-side benchmark comparison for Mellum2.1-12B-A2.5B-Thinking and Phi-4-reasoning-plus across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mellum2-1-12b-a2-5b-thinking-vs-phi-4-reasoning-plus
- Last updated: October 14, 2026

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Mellum2.1-12B-A2.5B-Thinking and Phi-4-reasoning-plus share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Mellum2.1-12B-A2.5B-Thinking has the larger published context window at 128K.

## Model Snapshot

| Property | Mellum2.1-12B-A2.5B-Thinking | Phi-4-reasoning-plus |
|----------|----------|----------|
| Creator | JetBrains | Microsoft |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 128K | 32K |
| Independent public score (not head-to-head) | null | null |
| Benchmarks Covered | 7 | 6 |
| Pricing (input/output) | $0.00 / $0.00 | N/A |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Phi-4-reasoning-plus public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Phi-4-reasoning-plus | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 17.4% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Phi-4-reasoning-plus public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Phi-4-reasoning-plus | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 82.0% | Coming soon | Coming soon |
| SWE-bench Verified | 47% | Coming soon | Coming soon |
| SWE-bench Pro | 28% | Coming soon | Coming soon |
| LiveCodeBench | Coming soon | 53.1% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Phi-4-reasoning-plus public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Phi-4-reasoning-plus | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 87.8% | Coming soon | Coming soon |
| GPQA-D | 64.6% | Coming soon | Coming soon |
| GPQA | Coming soon | 68.9% | Coming soon |
| MMLU-Pro | Coming soon | 76% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Phi-4-reasoning-plus public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Phi-4-reasoning-plus | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 90.6% | 84.9% | Mellum2.1-12B-A2.5B-Thinking |

### Mathematics

- Winner: Insufficient shared evidence
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon
- Phi-4-reasoning-plus public-lane score: Coming soon

| Benchmark | Mellum2.1-12B-A2.5B-Thinking | Phi-4-reasoning-plus | Winner |
|-----------|-----------|-----------|--------|
| AIME 2024 | Coming soon | 81.3% | Coming soon |
| AIME 2025 | Coming soon | 78% | Coming soon |

## FAQ

### Is there enough evidence to pick between Mellum2.1-12B-A2.5B-Thinking and Phi-4-reasoning-plus?

Not yet. The models share only 1 sourced benchmark row, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Mellum2.1-12B-A2.5B-Thinking vs Phi-4-reasoning](/compare/mellum2-1-12b-a2-5b-thinking-vs-phi-4-reasoning)
- [Phi-4-reasoning-plus vs Phi-4-reasoning](/compare/phi-4-reasoning-vs-phi-4-reasoning-plus)
- [Mellum2.1-12B-A2.5B-Thinking vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mellum2-1-12b-a2-5b-thinking)
- [Phi-4-reasoning-plus vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-phi-4-reasoning-plus)

## Explore More

- [Mellum2.1-12B-A2.5B-Thinking profile](/models/mellum2-1-12b-a2-5b-thinking)
- [Phi-4-reasoning-plus profile](/models/phi-4-reasoning-plus)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)