# GPT-6 Luna vs Mercury 3

> Side-by-side benchmark comparison for GPT-6 Luna and Mercury 3 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-6-luna-vs-mercury-3
- Last updated: October 19, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-6 Luna and Mercury 3 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 3 has the lower published output-token price.
- GPT-6 Luna has the larger published context window at 1.05M.

## Model Snapshot

| Property | GPT-6 Luna | Mercury 3 |
|----------|----------|----------|
| Creator | OpenAI | Inception |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1.05M | 1M |
| Independent public score (not head-to-head) | 66.56 | null |
| Benchmarks Covered | 17 | 8 |
| Pricing (input/output) | $0.10 / $0.50 | $0.10 / $0.35 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: 56.4 (Estimated · #38/130)
- Mercury 3 public-lane score: Coming soon

| Benchmark | GPT-6 Luna | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| ExploitGym | 11.6% | Coming soon | Coming soon |
| Hermes Index | 33.9% | Coming soon | Coming soon |
| Hermes Bench | 70.5% | Coming soon | Coming soon |
| MazeBench | 0% | Coming soon | Coming soon |
| τ³-bench results | Coming soon | 30.2% | Coming soon |
| BrowseComp+ | Coming soon | 55.18% | Coming soon |
| DeepSearchQA | Coming soon | 71.3% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: 53.3 (Supported · #38/151)
- Mercury 3 public-lane score: Coming soon

| Benchmark | GPT-6 Luna | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| DeepSWE | 66.6% | 46.3% | GPT-6 Luna |
| Bug Hunt Bench | 18.3 fixes | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: 59.6 (#25/27)
- Mercury 3 public-lane score: Coming soon

| Benchmark | GPT-6 Luna | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-1 | 86.67% | Coming soon | Coming soon |
| ARC-AGI-2 | 59.3% | Coming soon | Coming soon |
| ARC-AGI-3 | 0.1% | Coming soon | Coming soon |
| ARC-AGI-3 Provider Adapter | 0.59% | Coming soon | Coming soon |
| MRCRv2 | Coming soon | 75.5% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: 81.9 (Unranked · 1 rankable row)
- Mercury 3 public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: 67.4 (Supported · #27/186)
- Mercury 3 public-lane score: Coming soon

| Benchmark | GPT-6 Luna | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| HealthBench (raw) | 50.0% | Coming soon | Coming soon |
| HealthBench (length-adjusted) | 54.5% | Coming soon | Coming soon |
| HealthBench Professional | 60.8% | Coming soon | Coming soon |
| HealthBench Professional (raw) | 61.2% | Coming soon | Coming soon |
| HealthBench Hard | 31.4% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 89.2% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: Coming soon
- Mercury 3 public-lane score: Coming soon

| Benchmark | GPT-6 Luna | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| IFBench | Coming soon | 76.8% | Coming soon |
| MultiChallenge (provider reports) | Coming soon | 60.35% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- GPT-6 Luna public-lane score: 83.7 (Unranked · 2 rankable rows)
- Mercury 3 public-lane score: Coming soon

| Benchmark | GPT-6 Luna | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 78.947% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 56.098% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-6 Luna and Mercury 3?

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

- [GPT-6 Luna vs GPT-6.1 Sol](/compare/gpt-6-1-sol-vs-gpt-6-luna)
- [Mercury 3 vs GPT-6.1 Sol](/compare/gpt-6-1-sol-vs-mercury-3)
- [GPT-6 Luna vs GPT-6 Astra](/compare/gpt-6-astra-vs-gpt-6-luna)
- [Mercury 3 vs GPT-6 Astra](/compare/gpt-6-astra-vs-mercury-3)

## Explore More

- [GPT-6 Luna profile](/models/gpt-6-luna)
- [Mercury 3 profile](/models/mercury-3)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)