# Claude Sonnet 5 vs Ultramarine 1 Flash

> Side-by-side benchmark comparison for Claude Sonnet 5 and Ultramarine 1 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-5-vs-ultramarine-1-flash
- Last updated: October 15, 2026

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

## Quick Verdict

Evidence is too thin for a benchmark verdict: Claude Sonnet 5 and Ultramarine 1 Flash 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.
- Ultramarine 1 Flash has the lower published output-token price.
- Claude Sonnet 5 has the larger published context window at 1M.

## Model Snapshot

| Property | Claude Sonnet 5 | Ultramarine 1 Flash |
|----------|----------|----------|
| Creator | Anthropic | Paper Instruments |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | Not disclosed |
| Independent public score (not head-to-head) | 64.76 | null |
| Benchmarks Covered | 28 | 5 |
| Pricing (input/output) | $2.00 / $10.00 | $0.15 / $0.50 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Claude Sonnet 5 public-lane score: 66.4 (Supported · #15/126)
- Ultramarine 1 Flash public-lane score: Coming soon

| Benchmark | Claude Sonnet 5 | Ultramarine 1 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 14.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 80.4% | 83.2% | Ultramarine 1 Flash |
| BrowseComp | 84.7% | Coming soon | Coming soon |
| HLE w/ tools | 57.4% | Coming soon | Coming soon |
| OSWorld-Verified | 81.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 74.5% | Coming soon | Coming soon |
| ApprenticeBench | 16% | Coming soon | Coming soon |
| JobBench | Coming soon | 62.9% | Coming soon |
| AutomationBench | Coming soon | 50.2% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Claude Sonnet 5 public-lane score: 57.5 (Supported · #25/149)
- Ultramarine 1 Flash public-lane score: Coming soon

| Benchmark | Claude Sonnet 5 | Ultramarine 1 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85.2% | Coming soon | Coming soon |
| SWE-bench Pro | 63.2% | Coming soon | Coming soon |
| SWE Multilingual | 78.3% | Coming soon | Coming soon |
| SWE Multimodal | 28.1% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 80.4% | 83.2% | Ultramarine 1 Flash |
| FrontierCode 1.1 Main | 42.7% | Coming soon | Coming soon |
| CursorBench 3.2 | 61.5% | Coming soon | Coming soon |
| VulcanBench CII v1 | 89.2% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 82.4% | Coming soon | Coming soon |
| SWE-bench (Vals) | 79.6% | Coming soon | Coming soon |
| CursorBench 4.0 | 34.1% | Coming soon | Coming soon |
| DeepSWE | Coming soon | 61.5% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Claude Sonnet 5 public-lane score: 82.2 (Unranked · 2 rankable rows)
- Ultramarine 1 Flash public-lane score: Coming soon

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Claude Sonnet 5 public-lane score: 82 (#15/54)
- Ultramarine 1 Flash public-lane score: Coming soon

| Benchmark | Claude Sonnet 5 | Ultramarine 1 Flash | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | 88.3% | Coming soon | Coming soon |
| CharXiv w/o tools | 77% | Coming soon | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Claude Sonnet 5 public-lane score: 65.2 (Supported · #32/182)
- Ultramarine 1 Flash public-lane score: Coming soon

| Benchmark | Claude Sonnet 5 | Ultramarine 1 Flash | Winner |
|-----------|-----------|-----------|--------|
| HLE | 57.4% | Coming soon | Coming soon |
| HLE w/o tools | 43.2% | Coming soon | Coming soon |
| HLE-Verified | 31.0% | Coming soon | Coming soon |
| LABBench2 | 80.1% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 88.9% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 87.5% | Coming soon | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Claude Sonnet 5 public-lane score: 69.4 (Unranked · 2 rankable rows)
- Ultramarine 1 Flash public-lane score: Coming soon

| Benchmark | Claude Sonnet 5 | Ultramarine 1 Flash | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 65.614% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 29.268% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Claude Sonnet 5 and Ultramarine 1 Flash?

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

- [Claude Sonnet 5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-claude-sonnet-5)
- [Ultramarine 1 Flash vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-ultramarine-1-flash)
- [Claude Sonnet 5 vs GPT-6.1 Sol](/compare/claude-sonnet-5-vs-gpt-6-1-sol)
- [Ultramarine 1 Flash vs GPT-6.1 Sol](/compare/gpt-6-1-sol-vs-ultramarine-1-flash)

## Explore More

- [Claude Sonnet 5 profile](/models/claude-sonnet-5)
- [Ultramarine 1 Flash profile](/models/ultramarine-1-flash)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)