# Claude Sonnet 5.5 vs Mercury 3

> Side-by-side benchmark comparison for Claude Sonnet 5.5 and Mercury 3 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-5-5-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: Claude Sonnet 5.5 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.

## Model Snapshot

| Property | Claude Sonnet 5.5 | Mercury 3 |
|----------|----------|----------|
| Creator | Anthropic | Inception |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Independent public score (not head-to-head) | 82.22 | null |
| Benchmarks Covered | 53 | 8 |
| Pricing (input/output) | $2.00 / $10.00 | $0.10 / $0.35 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: 69.1 (Supported · #11/130)
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 4.0 | 70.60% | Coming soon | Coming soon |
| HLE w/ tools | 64.5% | Coming soon | Coming soon |
| DRACO | 87.0% | Coming soon | Coming soon |
| Terminal-Bench-Science 0.1 | 59.9% | Coming soon | Coming soon |
| LAB all-pass (Harvey held-out) | 10.0% | Coming soon | Coming soon |
| LAB criterion-pass (Harvey held-out) | 93.1% | Coming soon | Coming soon |
| Toolathlon Verified Pass@3 | 85.2% | Coming soon | Coming soon |
| Toolathlon Verified Pass³ | 68.5% | Coming soon | Coming soon |
| Toolathlon Verified avg. turns | 31.6 turns | Coming soon | Coming soon |
| AutomationBench (Zapier 1.0.6) | 44.70% | Coming soon | Coming soon |
| Toolathlon-Verified | 77.8% | Coming soon | Coming soon |
| Hermes Index | 53.1% | Coming soon | Coming soon |
| Hermes Bench | 73.5% | Coming soon | Coming soon |
| MazeBench | 8% | 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
- Claude Sonnet 5.5 public-lane score: 84.3 (Supported · #1/151)
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| FrontierCode 1.1 Main | 46.2% | Coming soon | Coming soon |
| CursorBench 4.0 | 55.5% | Coming soon | Coming soon |
| SWE-bench Pro | 81.3% | Coming soon | Coming soon |
| SWE Multilingual | 90.3% | Coming soon | Coming soon |
| SWE Multimodal | 54.3% | Coming soon | Coming soon |
| DeepSWE | 71.0% | 46.3% | Claude Sonnet 5.5 |
| FrontierCode 1.1 Extended | 59.1% | Coming soon | Coming soon |
| ProgramBench | 79.7% | Coming soon | Coming soon |
| FrontierSWE v2 | 61.9% | Coming soon | Coming soon |
| Bug Hunt Bench | 51.3 fixes | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: 81.8 (#6/27)
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| MRCRv2 | Coming soon | 75.5% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: 86.7 (Unranked · 7 rankable rows)
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| Chartography (no tools) | 61.6% | Coming soon | Coming soon |
| Chartography (tools) | 90.2% | Coming soon | Coming soon |
| BenchCAD Vision2Code (no tools) | 0.747 | Coming soon | Coming soon |
| BenchCAD Vision2Code (tools) | 0.963 | Coming soon | Coming soon |
| Biomedical image analysis | 72.2% | Coming soon | Coming soon |
| OfficeQA | 76.9% | Coming soon | Coming soon |
| OfficeQA Pro | 65.6% | Coming soon | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: 82.7 (Supported · #5/186)
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| HealthBench (raw) | 69.4% | Coming soon | Coming soon |
| HealthBench (length-adjusted) | 65.4% | Coming soon | Coming soon |
| HealthBench Professional (raw) | 77.1% | Coming soon | Coming soon |
| HealthBench Professional | 69.2% | Coming soon | Coming soon |
| BioMysteryBench (human-solvable) | 89.2% | Coming soon | Coming soon |
| BioMysteryBench (human-difficult) | 44.7% | Coming soon | Coming soon |
| SpatialBench Verified | 72.5% | Coming soon | Coming soon |
| SingleCellBench | 59.1% | Coming soon | Coming soon |
| Protein Design | 51.0% | Coming soon | Coming soon |
| Morphology-to-molecule matching | 25.0% | Coming soon | Coming soon |
| Medicinal chemistry | 65.3% | Coming soon | Coming soon |
| Protein Design library ranking | 54.8% | Coming soon | Coming soon |
| De novo protein-binder design | 82.3% | Coming soon | Coming soon |
| Protocols (troubleshooting) | 67.3% | Coming soon | Coming soon |
| Protocols (understanding) | 66.6% | Coming soon | Coming soon |
| HLE w/o tools | 56.9% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 89.2% | Coming soon |

### Multilingual

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: Coming soon
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| GMMLU | 92.1% | Coming soon | Coming soon |
| MILU | 91.6% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: Coming soon
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| IFBench | Coming soon | 76.8% | Coming soon |
| MultiChallenge (provider reports) | Coming soon | 60.35% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Claude Sonnet 5.5 public-lane score: 95.2 (Unranked · 4 rankable rows)
- Mercury 3 public-lane score: Coming soon

| Benchmark | Claude Sonnet 5.5 | Mercury 3 | Winner |
|-----------|-----------|-----------|--------|
| ArXivMath Aug. 2026 (no tools) | 86.8% | Coming soon | Coming soon |
| ArXivMath Aug. 2026 (tools) | 95.2% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 88.772% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 80.488% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Claude Sonnet 5.5 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

- [Claude Sonnet 5.5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-claude-sonnet-5-5)
- [Mercury 3 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mercury-3)
- [Claude Sonnet 5.5 vs GPT-6.1 Sol](/compare/claude-sonnet-5-5-vs-gpt-6-1-sol)
- [Mercury 3 vs GPT-6.1 Sol](/compare/gpt-6-1-sol-vs-mercury-3)

## Explore More

- [Claude Sonnet 5.5 profile](/models/claude-sonnet-5-5)
- [Mercury 3 profile](/models/mercury-3)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)