# Claude Opus 5 vs GPT-5.5 Instant

> Claude Opus 5 is the stronger model overall, scoring 67.8 to 42.7 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-opus-5-vs-gpt-5-5-instant
- Last updated: 2026-10-12
- Shared benchmarks: 27

## Summary

- They share 27 benchmarks with published results for both. Claude Opus 5 scores higher in 9 categories and GPT-5.5 Instant in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5 leads 86.2 to 26.5.
- The biggest single-benchmark swing is FrontierMath Tier 4: 73.2% for Claude Opus 5 and 2.4% for GPT-5.5 Instant.

## Snapshot

| | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 67.8 | 42.7 |
| Rank | 4 | 110 |
| Context | 1M | — |
| Input $/M | $5 | — |
| Output $/M | $25 | — |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Opus 5: 67.5 (#5)
- GPT-5.5 Instant: 44.3 (#74)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| SciCode | 56.4% | 48.6% |
| LMArena Coding | 1534 | 1433 |
| DeepSWE | 73.6% | — |
| FrontierCode | 53.4% | — |
| CursorBench | 46.6% | — |
| LMArena WebDev | 1691 | — |
| FrontierSWE | 52% | — |
| WeirdML | 91.8% | — |
| ALE-Bench | 2,165 | — |

## Agentic & Tool Use

- Claude Opus 5: 55.6 (#1)
- GPT-5.5 Instant: —

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| APEX-Agents | 65.8% | — |
| OSWorld 2.0 | 31.4% | — |
| τ²-bench Banking | 48.7% | — |
| PostTrainBench | 35% | — |
| BALROG | 63.4% | — |
| GBAEval | 79.6% | — |
| GDP.pdf | 24% | — |
| Vending-Bench 2 | 11,182 | — |

## Reasoning

- Claude Opus 5: 77.2 (#4)
- GPT-5.5 Instant: 24.9 (#155)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| CritPt | 29.1% | 0% |
| Chess Puzzles | 42% | 12% |
| LMArena Hard Prompts | 1526 | 1426 |
| Epoch Capabilities Index | 162.78 | 142.52 |
| ARC-AGI-2 | 90.4% | — |
| SimpleBench | 80.6% | — |
| NYT Connections (extended) | 94.3% | — |
| ARC-AGI-1 | 97.5% | — |
| EBR-Bench | 45.7% | — |
| Mystery Game Puzzles | 59% | — |
| DTBench | 97.9% | — |
| LMCA | 64.5% | — |
| Bench to the Future 3 | 0.12 | — |

## Math

- Claude Opus 5: 86.2 (#8)
- GPT-5.5 Instant: 26.5 (#259)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| FrontierMath (Tiers 1-3) | 85.6% | 26.3% |
| FrontierMath Tier 4 | 73.2% | 2.4% |
| OTIS Mock AIME 2024-2025 | 98.9% | 68.1% |
| LMArena Math | 1531 | 1420 |
| ProofBench | 99% | — |

## Knowledge

- Claude Opus 5: 66.8 (#9)
- GPT-5.5 Instant: 48.9 (#74)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| GPQA Diamond | 93.9% | 82.5% |
| LMArena Expert | 1557 | 1409 |
| SimpleQA Verified | 59.9% | — |

## Multimodal

- Claude Opus 5: 50.8 (#8)
- GPT-5.5 Instant: 40.0 (#52)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| LMArena Vision | 1319 | 1250 |
| LMArena Document | 1516 | 1403 |
| Blueprint-Bench 2 | 30.4% | — |
| Furniture Assembly | 60.8% | — |

## Multilingual

- Claude Opus 5: 58.8 (#4)
- GPT-5.5 Instant: 52.8 (#80)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| LMArena Non-English | 1501 | 1417 |
| LMArena Chinese | 1574 | 1456 |
| LMArena French | 1519 | 1428 |
| LMArena German | 1524 | 1411 |
| LMArena Japanese | 1516 | 1408 |
| LMArena Korean | 1521 | 1392 |
| LMArena Russian | 1507 | 1431 |
| LMArena Spanish | 1519 | 1429 |

## Instruction Following

- Claude Opus 5: 79.2 (#7)
- GPT-5.5 Instant: 74.2 (#100)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| LMArena Instruction Following | 1517 | 1406 |

## Long Context

- Claude Opus 5: 46.5 (#21)
- GPT-5.5 Instant: 43.4 (#96)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| LMArena Longer Query | 1515 | 1422 |

## Writing & Preference

- Claude Opus 5: 79.2 (#1)
- GPT-5.5 Instant: 61.8 (#85)

| Benchmark | Claude Opus 5 | GPT-5.5 Instant |
|---|---|---|
| LMArena Text | 1507 | 1419 |
| LMArena Creative Writing | 1491 | 1419 |
| LMArena Multi-Turn | 1499 | 1433 |
| EQ-Bench Creative Writing | 2133 | — |
| EQ-Bench 4 | 1385 | — |

## FAQ

### Is Claude Opus 5 better than GPT-5.5 Instant?

Claude Opus 5 is the stronger model overall, scoring 67.8 to 42.7 on the Noometry Index.

### Is Claude Opus 5 or GPT-5.5 Instant better for coding?

Claude Opus 5 scores higher on coding benchmarks: 67.5 versus 44.3 in the Noometry coding category.

### How many benchmarks do Claude Opus 5 and GPT-5.5 Instant share?

27 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and GPT-5.5 Instant has 27.