# Claude Opus 4.8 vs Claude Sonnet 5.5

> Side-by-side benchmark comparison for Claude Opus 4.8 and Claude Sonnet 5.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-opus-4-8-vs-claude-sonnet-5-5
- Last updated: September 28, 2026

- Shared sourced benchmarks: 6
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Pick Claude Sonnet 5.5 if you want the stronger benchmark profile. Claude Opus 4.8 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Claude Sonnet 5.5 leads overall 80.49 to 70.39.
- The clearest category separation is in reasoning, where the averages are 59.1 for Claude Opus 4.8 and 79.2 for Claude Sonnet 5.5.
- The biggest single benchmark swing is SWE Multimodal in Coding, with scores of 38.4% and 54.3%.
- Claude Sonnet 5.5 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.

## Model Snapshot

| Property | Claude Opus 4.8 | Claude Sonnet 5.5 |
|----------|----------|----------|
| Creator | Anthropic | Anthropic |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 70.39 | 80.49 |
| Benchmarks Covered | 38 | 47 |
| Pricing (input/output) | $5.00 / $25.00 | $2.00 / $10.00 |

## Category Breakdown

### Agentic

- Winner: Claude Sonnet 5.5
- Claude Opus 4.8 public-lane score: 61.6 (Supported · #14/111)
- Claude Sonnet 5.5 public-lane score: 66.1 (Supported · #10/111)

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 21.1% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 74.6% | Coming soon | Coming soon |
| BrowseComp | 84.3% | Coming soon | Coming soon |
| DeepSearchQA | 93.1% | Coming soon | Coming soon |
| OSWorld-Verified | 83.4% | Coming soon | Coming soon |
| Finance Agent v2 | 53.9% | Coming soon | Coming soon |
| MCP Atlas | 82.2% | Coming soon | Coming soon |
| Toolathlon | 59.9% | Coming soon | Coming soon |
| Gert Labs | 72.97% | Coming soon | Coming soon |
| ResearchClawBench | 21.1% | Coming soon | Coming soon |
| OSWorld 2.0 | 20.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 71.9% | Coming soon | Coming soon |
| Terminal-Bench 4.0 | Coming soon | 70.60% | Coming soon |
| HLE w/ tools | Coming soon | 64.5% | Coming soon |
| DRACO | Coming soon | 87.0% | Coming soon |
| Terminal-Bench-Science 0.1 | Coming soon | 59.9% | Coming soon |
| LAB all-pass (Harvey held-out) | Coming soon | 10.0% | Coming soon |
| LAB criterion-pass (Harvey held-out) | Coming soon | 93.1% | Coming soon |
| Toolathlon Verified Pass@3 | Coming soon | 85.2% | Coming soon |
| Toolathlon Verified Pass³ | Coming soon | 68.5% | Coming soon |
| Toolathlon Verified avg. turns | Coming soon | 31.6 turns | Coming soon |
| AutomationBench (Zapier 1.0.6) | Coming soon | 44.7% | Coming soon |
| Toolathlon-Verified | Coming soon | 77.8% | Coming soon |

### Coding

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 62.2 (Supported · #13/136)
- Claude Sonnet 5.5 public-lane score: 79.6 (Estimated · #3/136)

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 88.6% | Coming soon | Coming soon |
| SWE-bench Pro | 69.2% | 81.3% | Claude Sonnet 5.5 |
| SWE Multilingual | 84.4% | 90.3% | Claude Sonnet 5.5 |
| SWE Multimodal | 38.4% | 54.3% | Claude Sonnet 5.5 |
| Terminal-Bench 2.1 | 74.6% | Coming soon | Coming soon |
| cursorBench31 | 58.4% | Coming soon | Coming soon |
| cursorBench32 | 62.3% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 46.5% | 46.2% | Claude Opus 4.8 |
| LiveCodeBench (Vals) | 87.8% | Coming soon | Coming soon |
| SWE-bench (Vals) | 88.6% | Coming soon | Coming soon |
| cursorBench40 | Coming soon | 55.5% | Coming soon |
| DeepSWE | Coming soon | 71.0% | Coming soon |
| FrontierCode 1.1 Extended | Coming soon | 59.1% | Coming soon |
| ProgramBench | Coming soon | 79.7% | Coming soon |
| FrontierSWE v2 | Coming soon | 61.9% | Coming soon |

### Reasoning

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 59.1 (#22/27)
- Claude Sonnet 5.5 public-lane score: 79.2 (#7/27)

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 72.1% | Coming soon | Coming soon |
| ARC-AGI-3 | 1.5% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 87.7 (#7/50)
- Claude Sonnet 5.5 public-lane score: 83.3 (Unranked · 7 rankable rows)

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | 66.2% | 65.6% | Claude Opus 4.8 |
| ScreenSpot Pro | 87.9% | Coming soon | Coming soon |
| CharXiv | 89.9% | Coming soon | Coming soon |
| CharXiv w/o tools | 80.5% | Coming soon | Coming soon |
| Chartography (no tools) | Coming soon | 61.6% | Coming soon |
| Chartography (tools) | Coming soon | 90.2% | Coming soon |
| BenchCAD Vision2Code (no tools) | Coming soon | 0.747 | Coming soon |
| BenchCAD Vision2Code (tools) | Coming soon | 0.963 | Coming soon |
| Biomedical image analysis | Coming soon | 72.2% | Coming soon |
| OfficeQA | Coming soon | 76.9% | Coming soon |

### Knowledge

- Winner: Claude Sonnet 5.5
- Claude Opus 4.8 public-lane score: 70 (Supported · #12/160)
- Claude Sonnet 5.5 public-lane score: 80.9 (Supported · #6/160)

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 93.6% | Coming soon | Coming soon |
| GPQA-D | 93.6% | Coming soon | Coming soon |
| HLE | 57.9% | Coming soon | Coming soon |
| HLE w/o tools | 49.8% | 56.9% | Claude Sonnet 5.5 |
| GPQA Diamond (Vals) | 92.4% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 89.6% | Coming soon | Coming soon |
| HealthBench (raw) | Coming soon | 69.4% | Coming soon |
| HealthBench (length-adjusted) | Coming soon | 65.4% | Coming soon |
| HealthBench Professional (raw) | Coming soon | 77.1% | Coming soon |
| HealthBench Professional | Coming soon | 69.2% | Coming soon |
| BioMysteryBench (human-solvable) | Coming soon | 89.2% | Coming soon |
| BioMysteryBench (human-difficult) | Coming soon | 44.7% | Coming soon |
| SpatialBench Verified | Coming soon | 72.5% | Coming soon |
| SingleCellBench | Coming soon | 59.1% | Coming soon |
| Protein Design | Coming soon | 51.0% | Coming soon |
| Morphology-to-molecule matching | Coming soon | 25.0% | Coming soon |
| Medicinal chemistry | Coming soon | 65.3% | Coming soon |
| Protein Design library ranking | Coming soon | 54.8% | Coming soon |
| De novo protein-binder design | Coming soon | 82.3% | Coming soon |
| Protocols (troubleshooting) | Coming soon | 67.3% | Coming soon |
| Protocols (understanding) | Coming soon | 66.6% | Coming soon |

### Multilingual

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: Coming soon
- Claude Sonnet 5.5 public-lane score: Coming soon

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| INCLUDE | 87.6% | Coming soon | Coming soon |
| GMMLU | Coming soon | 92.1% | Coming soon |
| MILU | Coming soon | 91.6% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 74 (#60/124)
- Claude Sonnet 5.5 public-lane score: Coming soon

### Mathematics

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 65.2 (#2/7)
- Claude Sonnet 5.5 public-lane score: Coming soon

| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Winner |
|-----------|-----------|-----------|--------|
| USAMO 2026 | 96.7% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 47.241% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 31.250% | Coming soon | Coming soon |
| ArXivMath Aug. 2026 (no tools) | Coming soon | 86.8% | Coming soon |
| ArXivMath Aug. 2026 (tools) | Coming soon | 95.2% | Coming soon |

## FAQ

### Which is better overall, Claude Opus 4.8 or Claude Sonnet 5.5?

Claude Sonnet 5.5 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Opus 4.8 and Claude Sonnet 5.5?

The widest category gap is in reasoning, where the averages are 59.1 for Claude Opus 4.8 and 79.2 for Claude Sonnet 5.5.

### How many benchmarks does Claude Opus 4.8 cover on BenchLM?

Claude Opus 4.8 currently has 38 sourced benchmark scores on BenchLM.

### How many benchmarks does Claude Sonnet 5.5 cover on BenchLM?

Claude Sonnet 5.5 currently has 47 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Opus 4.8 vs GPT-6 Astra](/compare/claude-opus-4-8-vs-gpt-6-astra)
- [Claude Sonnet 5.5 vs GPT-6 Astra](/compare/claude-sonnet-5-5-vs-gpt-6-astra)
- [Claude Opus 4.8 vs Claude Opus 5.5](/compare/claude-opus-4-8-vs-claude-opus-5-5)
- [Claude Sonnet 5.5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-claude-sonnet-5-5)

## Explore More

- [Claude Opus 4.8 profile](/models/claude-opus-4-8)
- [Claude Sonnet 5.5 profile](/models/claude-sonnet-5-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)