# Mellum2-12B-A2.5B-Instruct vs Mercury 2.5

> Side-by-side benchmark comparison for Mellum2-12B-A2.5B-Instruct and Mercury 2.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mellum2-12b-a2-5b-instruct-vs-mercury-2-5
- Last updated: September 8, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: Mellum2-12B-A2.5B-Instruct and Mercury 2.5 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.
- Mercury 2.5 has the larger published context window at 260K.

## Model Snapshot

| Property | Mellum2-12B-A2.5B-Instruct | Mercury 2.5 |
|----------|----------|----------|
| Creator | JetBrains | Inception |
| Type | Open Weight | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 128K | 260K |
| Independent public score (not head-to-head) | null | null |
| Benchmarks Covered | 6 | 5 |
| Pricing (input/output) | N/A | $0.04 / $0.15 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: 46.1 (Estimated · #81/152)
- Mercury 2.5 public-lane score: 44.5 (Estimated · #91/152)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| BFCL v4 | 44.2% | Coming soon | Coming soon |
| τ³-bench results | Coming soon | 96.0% | Coming soon |
| DeepSearchQA | Coming soon | 34.0% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Mercury 2.5 public-lane score: 47.8 (Estimated · #73/151)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 37.2% | Coming soon | Coming soon |
| SciCode | Coming soon | 38% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Mercury 2.5 public-lane score: 67.7 (Unranked · 1 rankable row)

### Knowledge

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: 46.4 (Estimated · #104/182)
- Mercury 2.5 public-lane score: 48.3 (Estimated · #94/182)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Redux | 78.1% | Coming soon | Coming soon |
| GPQA | 40.9% | Coming soon | Coming soon |
| GPQA-D | 40.9% | 79.0% | Mercury 2.5 |

### Instruction Following

- Winner: Insufficient shared evidence
- Mellum2-12B-A2.5B-Instruct public-lane score: Coming soon
- Mercury 2.5 public-lane score: 80.1 (#53/121)

| Benchmark | Mellum2-12B-A2.5B-Instruct | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 75.8% | Coming soon | Coming soon |
| IFBench | Coming soon | 77% | Coming soon |

## FAQ

### Is there enough evidence to pick between Mellum2-12B-A2.5B-Instruct and Mercury 2.5?

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

- [Mellum2-12B-A2.5B-Instruct vs Mellum2-12B-A2.5B-Thinking](/compare/mellum2-12b-a2-5b-instruct-vs-mellum2-12b-a2-5b-thinking)
- [Mercury 2.5 vs Mellum2-12B-A2.5B-Thinking](/compare/mellum2-12b-a2-5b-thinking-vs-mercury-2-5)
- [Mellum2-12B-A2.5B-Instruct vs Mercury 2.5 Preview](/compare/mellum2-12b-a2-5b-instruct-vs-mercury-2-5-preview)
- [Mercury 2.5 vs Mercury 2.5 Preview](/compare/mercury-2-5-vs-mercury-2-5-preview)

## Explore More

- [Mellum2-12B-A2.5B-Instruct profile](/models/mellum2-12b-a2-5b-instruct)
- [Mercury 2.5 profile](/models/mercury-2-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)