# Mercury 3 vs Step 5 Preview

> Side-by-side benchmark comparison for Mercury 3 and Step 5 Preview across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mercury-3-vs-step-5-preview
- Last updated: October 19, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Mercury 3 and Step 5 Preview share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are 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 | Mercury 3 | Step 5 Preview |
|----------|----------|----------|
| Creator | Inception | StepFun |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Independent public score (not head-to-head) | null | 69.57 |
| Benchmarks Covered | 8 | 24 |
| Pricing (input/output) | $0.10 / $0.35 | $1.00 / $2.70 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Mercury 3 public-lane score: Coming soon
- Step 5 Preview public-lane score: 65.2 (Estimated · #18/130)

| Benchmark | Mercury 3 | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| τ³-bench results | 30.2% | Coming soon | Coming soon |
| BrowseComp+ | 55.18% | Coming soon | Coming soon |
| DeepSearchQA | 71.3% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 85.0% | Coming soon |
| Terminal-Bench 4.0 | Coming soon | 33.30% | Coming soon |
| CyberGym | Coming soon | 84.7% | Coming soon |
| AutomationBench | Coming soon | 44.0% | Coming soon |
| Toolathlon-Verified | Coming soon | 74.1% | Coming soon |
| MCP Atlas | Coming soon | 85.6% | Coming soon |
| JobBench | Coming soon | 59.0% | Coming soon |
| APEX-Agents | Coming soon | 37.8% | Coming soon |
| DRACO | Coming soon | 83.3% | Coming soon |
| BrowseComp | Coming soon | 88.7% | Coming soon |
| Agents' Last Exam | Coming soon | 29.5% | Coming soon |
| Hermes Index | Coming soon | 32.8% | Coming soon |
| Hermes Bench | Coming soon | 69.2% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Mercury 3 public-lane score: Coming soon
- Step 5 Preview public-lane score: 60.6 (Estimated · #21/151)

| Benchmark | Mercury 3 | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| DeepSWE | 46.3% | 67.7% | Step 5 Preview |
| Terminal-Bench 2.1 | Coming soon | 85.0% | Coming soon |
| SciCode | Coming soon | 58.9% | Coming soon |
| ProgramBench | Coming soon | 80.5% | Coming soon |
| sweMarathon | Coming soon | 72.7% | Coming soon |
| MLS-Bench Lite | Coming soon | 40.5% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Mercury 3 public-lane score: Coming soon
- Step 5 Preview public-lane score: 82.5 (Unranked · 2 rankable rows)

| Benchmark | Mercury 3 | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| MRCRv2 | 75.5% | Coming soon | Coming soon |
| CritPt | Coming soon | 20.9% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Mercury 3 public-lane score: Coming soon
- Step 5 Preview public-lane score: 74.6 (#24/55)

| Benchmark | Mercury 3 | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | Coming soon | 60.3% | Coming soon |
| MMMU-Pro | Coming soon | 76% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Mercury 3 public-lane score: Coming soon
- Step 5 Preview public-lane score: 68.8 (Supported · #22/186)

| Benchmark | Mercury 3 | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 89.2% | 93.5% | Step 5 Preview |
| HLE | Coming soon | 46.5% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Mercury 3 public-lane score: Coming soon
- Step 5 Preview public-lane score: Coming soon

| Benchmark | Mercury 3 | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| IFBench | 76.8% | Coming soon | Coming soon |
| MultiChallenge (provider reports) | 60.35% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Mercury 3 and Step 5 Preview?

Not yet. The models share only 2 sourced benchmark rows, 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

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

## Explore More

- [Mercury 3 profile](/models/mercury-3)
- [Step 5 Preview profile](/models/step-5-preview)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)