# GPT-5.5 Pro vs Step 5 Preview

> Side-by-side benchmark comparison for GPT-5.5 Pro and Step 5 Preview across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-5-pro-vs-step-5-preview
- Last updated: September 21, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-5.5 Pro 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.
- Step 5 Preview has the lower published output-token price.

## Model Snapshot

| Property | GPT-5.5 Pro | Step 5 Preview |
|----------|----------|----------|
| Creator | OpenAI | StepFun |
| Type | Proprietary | Pending |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Independent public score (not head-to-head) | 62.06 | null |
| Benchmarks Covered | 6 | 22 |
| Pricing (input/output) | $30.00 / $180.00 | $1.00 / $2.70 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.5 Pro public-lane score: 59 (Estimated · #28/154)
- Step 5 Preview public-lane score: Coming soon

| Benchmark | GPT-5.5 Pro | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| BrowseComp | 90.1% | 88.7% | GPT-5.5 Pro |
| 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 |
| Agents' Last Exam | Coming soon | 29.5% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.5 Pro public-lane score: Coming soon
- Step 5 Preview public-lane score: Coming soon

| Benchmark | GPT-5.5 Pro | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| DeepSWE | Coming soon | 67.7% | Coming soon |
| 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
- GPT-5.5 Pro public-lane score: Coming soon
- Step 5 Preview public-lane score: 78.5 (Unranked · 2 rankable rows)

| Benchmark | GPT-5.5 Pro | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| CritPt | Coming soon | 20.9% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.5 Pro public-lane score: Coming soon
- Step 5 Preview public-lane score: 61.2 (#28/49)

| Benchmark | GPT-5.5 Pro | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | Coming soon | 60.3% | Coming soon |
| MMMU-Pro | Coming soon | 76% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.5 Pro public-lane score: 59.5 (Estimated · #38/186)
- Step 5 Preview public-lane score: Coming soon

| Benchmark | GPT-5.5 Pro | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| HLE | 57.2% | 46.5% | GPT-5.5 Pro |
| HLE w/o tools | 43.1% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 93.5% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.5 Pro public-lane score: 70.1 (Unranked · 3 rankable rows)
- Step 5 Preview public-lane score: Coming soon

| Benchmark | GPT-5.5 Pro | Step 5 Preview | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath (legacy) | 52.4% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 51.000% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 39.600% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-5.5 Pro 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

- [GPT-5.5 Pro vs GPT-5.5](/compare/gpt-5-5-vs-gpt-5-5-pro)
- [Step 5 Preview vs GPT-5.5](/compare/gpt-5-5-vs-step-5-preview)
- [GPT-5.5 Pro vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gpt-5-5-pro)
- [Step 5 Preview vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-step-5-preview)

## Explore More

- [GPT-5.5 Pro profile](/models/gpt-5-5-pro)
- [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)