# DeepSeek V4.1 Flash vs Mercury 2.5

> Side-by-side benchmark comparison for DeepSeek V4.1 Flash and Mercury 2.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/deepseek-v4-1-flash-vs-mercury-2-5
- Last updated: September 10, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: DeepSeek V4.1 Flash 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 lower published output-token price.
- DeepSeek V4.1 Flash has the larger published context window at 1M.

## Model Snapshot

| Property | DeepSeek V4.1 Flash | Mercury 2.5 |
|----------|----------|----------|
| Creator | DeepSeek | Inception |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 260K |
| Independent public score (not head-to-head) | null | null |
| Benchmarks Covered | 21 | 5 |
| Pricing (input/output) | $0.30 / $1.20 | $0.04 / $0.15 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: 44.6 (Estimated · #91/152)

| Benchmark | DeepSeek V4.1 Flash | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 90.6% | Coming soon | Coming soon |
| terminalBench3 | 30% | Coming soon | Coming soon |
| Terminal-Bench 4.0 | 31.20% | Coming soon | Coming soon |
| CyberGym | 88.1% | Coming soon | Coming soon |
| ExploitGym | 15.3% | Coming soon | Coming soon |
| HLE w/ tools | 63.9% | Coming soon | Coming soon |
| AutomationBench | 54.8% | Coming soon | Coming soon |
| Agents' Last Exam | 31.8% | 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
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: 47.8 (Estimated · #72/151)

| Benchmark | DeepSeek V4.1 Flash | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| Codeforces | 3471.0 | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 90.6% | Coming soon | Coming soon |
| terminalBench3 | 30% | Coming soon | Coming soon |
| DeepSWE | 74.2% | Coming soon | Coming soon |
| ProgramBench | 20.3% | Coming soon | Coming soon |
| NL2Repo | 65.4% | Coming soon | Coming soon |
| SciCode | Coming soon | 38% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: Coming soon

| Benchmark | DeepSeek V4.1 Flash | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| Chartography (tools) | 78.9% | Coming soon | Coming soon |
| BabyVision w/ Python | 89.6% | Coming soon | Coming soon |
| ZeroBench w/ Python | 49.0% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: 67.7 (Unranked · 1 rankable row)

### Knowledge

- Winner: Insufficient shared evidence
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: 48.4 (Estimated · #94/182)

| Benchmark | DeepSeek V4.1 Flash | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 90.9% | Coming soon | Coming soon |
| GPQA-D | 90.9% | 79.0% | DeepSeek V4.1 Flash |
| HLE | 36.8% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: 80.1 (#53/121)

| Benchmark | DeepSeek V4.1 Flash | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| IFBench | Coming soon | 77% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- DeepSeek V4.1 Flash public-lane score: Coming soon
- Mercury 2.5 public-lane score: Coming soon

| Benchmark | DeepSeek V4.1 Flash | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| Apex | 65.6% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between DeepSeek V4.1 Flash 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

- [DeepSeek V4.1 Flash vs Mercury 2.5 Preview](/compare/deepseek-v4-1-flash-vs-mercury-2-5-preview)
- [Mercury 2.5 vs Mercury 2.5 Preview](/compare/mercury-2-5-vs-mercury-2-5-preview)
- [DeepSeek V4.1 Flash vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-deepseek-v4-1-flash)
- [Mercury 2.5 vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-mercury-2-5)

## Explore More

- [DeepSeek V4.1 Flash profile](/models/deepseek-v4-1-flash)
- [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)