# Grok 4.1 Fast (Reasoning) vs Mercury 2.5

> Side-by-side benchmark comparison for Grok 4.1 Fast (Reasoning) and Mercury 2.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/grok-4-1-fast-reasoning-vs-mercury-2-5
- Last updated: September 8, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for Grok 4.1 Fast (Reasoning) and Mercury 2.5.

## Summary

- Grok 4.1 Fast (Reasoning) and Mercury 2.5 do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | Grok 4.1 Fast (Reasoning) | Mercury 2.5 |
|----------|----------|----------|
| Creator | xAI | Inception |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 2M | 260K |
| Independent public score (not head-to-head) | 54.98 | null |
| Benchmarks Covered | 1 | 5 |
| Pricing (input/output) | N/A | $0.04 / $0.15 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: Coming soon
- Mercury 2.5 public-lane score: 44.5 (Estimated · #91/152)

| Benchmark | Grok 4.1 Fast (Reasoning) | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| τ³-bench results | Coming soon | 96.0% | Coming soon |
| DeepSearchQA | Coming soon | 34.0% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 46.1 (Estimated · #86/151)
- Mercury 2.5 public-lane score: 47.8 (Estimated · #73/151)

| Benchmark | Grok 4.1 Fast (Reasoning) | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 1.20% | Coming soon | Coming soon |
| SciCode | Coming soon | 38% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 53.3 (Unranked · 1 rankable row)
- Mercury 2.5 public-lane score: Coming soon

### Reasoning

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 71.9 (Unranked · 2 rankable rows)
- Mercury 2.5 public-lane score: 67.7 (Unranked · 1 rankable row)

### Knowledge

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 49.6 (Estimated · #83/182)
- Mercury 2.5 public-lane score: 48.3 (Estimated · #94/182)

| Benchmark | Grok 4.1 Fast (Reasoning) | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | Coming soon | 79.0% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Grok 4.1 Fast (Reasoning) public-lane score: 63.1 (#70/121)
- Mercury 2.5 public-lane score: 80.1 (#53/121)

| Benchmark | Grok 4.1 Fast (Reasoning) | Mercury 2.5 | Winner |
|-----------|-----------|-----------|--------|
| IFBench | Coming soon | 77% | Coming soon |

## FAQ

### Can I compare Grok 4.1 Fast (Reasoning) and Mercury 2.5 on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

- [Grok 4.1 Fast (Reasoning) vs Grok 4.1 Fast](/compare/grok-4-1-fast-vs-grok-4-1-fast-reasoning)
- [Mercury 2.5 vs Grok 4.1 Fast](/compare/grok-4-1-fast-vs-mercury-2-5)
- [Grok 4.1 Fast (Reasoning) vs Mercury 2.5 Preview](/compare/grok-4-1-fast-reasoning-vs-mercury-2-5-preview)
- [Mercury 2.5 vs Mercury 2.5 Preview](/compare/mercury-2-5-vs-mercury-2-5-preview)

## Explore More

- [Grok 4.1 Fast (Reasoning) profile](/models/grok-4-1-fast-reasoning)
- [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)