# GPT-OSS 20B vs Mercury 2.5 Preview

> Side-by-side benchmark comparison for GPT-OSS 20B and Mercury 2.5 Preview across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-oss-20b-vs-mercury-2-5-preview
- Last updated: October 17, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for GPT-OSS 20B and Mercury 2.5 Preview.

## Summary

- GPT-OSS 20B and Mercury 2.5 Preview 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 | GPT-OSS 20B | Mercury 2.5 Preview |
|----------|----------|----------|
| Creator | OpenAI | Inception |
| Type | Open Weight | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 128K | 260K |
| Independent public score (not head-to-head) | 33.32 | null |
| Benchmarks Covered | 7 | 0 |
| Pricing (input/output) | $0.00 / $0.00 | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-OSS 20B public-lane score: 14.9 (Estimated · #115/128)
- Mercury 2.5 Preview public-lane score: Coming soon

### Coding

- Winner: Insufficient shared evidence
- GPT-OSS 20B public-lane score: 18.2 (Estimated · #123/150)
- Mercury 2.5 Preview public-lane score: Coming soon

| Benchmark | GPT-OSS 20B | Mercury 2.5 Preview | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 60.7% | Coming soon | Coming soon |
| React Native Evals | 71% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-OSS 20B public-lane score: 49.7 (Unranked · 2 rankable rows)
- Mercury 2.5 Preview public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- GPT-OSS 20B public-lane score: 33.9 (Supported · #140/184)
- Mercury 2.5 Preview public-lane score: Coming soon

| Benchmark | GPT-OSS 20B | Mercury 2.5 Preview | Winner |
|-----------|-----------|-----------|--------|
| MMLU | 85.3% | Coming soon | Coming soon |
| GPQA | 71.5% | Coming soon | Coming soon |
| HLE | 10.9% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-OSS 20B public-lane score: 79.2 (#60/148)
- Mercury 2.5 Preview public-lane score: Coming soon

### Mathematics

- Winner: Insufficient shared evidence
- GPT-OSS 20B public-lane score: Coming soon
- Mercury 2.5 Preview public-lane score: Coming soon

| Benchmark | GPT-OSS 20B | Mercury 2.5 Preview | Winner |
|-----------|-----------|-----------|--------|
| AIME 2024 | 92.1% | Coming soon | Coming soon |
| AIME 2025 | 91.7% | Coming soon | Coming soon |

## FAQ

### Can I compare GPT-OSS 20B and Mercury 2.5 Preview 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

- [GPT-OSS 20B vs GPT-OSS 120B](/compare/gpt-oss-120b-vs-gpt-oss-20b)
- [Mercury 2.5 Preview vs GPT-OSS 120B](/compare/gpt-oss-120b-vs-mercury-2-5-preview)
- [GPT-OSS 20B vs Mercury 2.5](/compare/gpt-oss-20b-vs-mercury-2-5)
- [Mercury 2.5 Preview vs Mercury 2.5](/compare/mercury-2-5-vs-mercury-2-5-preview)

## Explore More

- [GPT-OSS 20B profile](/models/gpt-oss-20b)
- [Mercury 2.5 Preview profile](/models/mercury-2-5-preview)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)