# Claude Opus 5.5 vs GPT-5.3 Chat

> Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 42.8 on the Noometry Index. GPT-5.3 Chat costs 1.7× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-opus-5-5-vs-gpt-5-3-chat
- Last updated: 2026-10-12
- Shared benchmarks: 15

## Summary

- They share 15 benchmarks with published results for both. Claude Opus 5.5 scores higher in 8 categories and GPT-5.3 Chat in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5.5 leads 91.8 to 38.2.
- GPT-5.3 Chat is cheaper at $1.75 / $14 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
- Claude Opus 5.5 accepts more context: 1M tokens versus 128K.

## Snapshot

| | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 68.6 | 42.8 |
| Rank | 3 | 109 |
| Context | 1M | 128K |
| Input $/M | $4 | $1.75 |
| Output $/M | $20 | $14 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Opus 5.5: 71.9 (#3)
- GPT-5.3 Chat: 41.4 (#124)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Coding | 1547 | 1408 |
| FrontierCode | 54.6% | — |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1813 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| MirrorCode | 77.4% | — |
| ALE-Bench | 2,147 | — |

## Agentic & Tool Use

- Claude Opus 5.5: 45.3 (#15)
- GPT-5.3 Chat: —

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| APEX-Agents | 73.5% | — |
| GDP.pdf | 30.6% | — |
| Vending-Bench 2 | 9,235 | — |

## Reasoning

- Claude Opus 5.5: 80.2 (#3)
- GPT-5.3 Chat: 28.5 (#102)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Hard Prompts | 1535 | 1399 |
| ARC-AGI-2 | 93.3% | — |
| NYT Connections (extended) | 88.5% | — |
| ARC-AGI-1 | 98.5% | — |
| CritPt | 31.7% | — |
| EBR-Bench | 71.4% | — |
| Mystery Game Puzzles | 71% | — |
| DTBench | 98.9% | — |
| LMCA | 68.2% | — |
| Epoch Capabilities Index | 167.33 | — |

## Math

- Claude Opus 5.5: 91.8 (#3)
- GPT-5.3 Chat: 38.2 (#142)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Math | 1506 | 1389 |
| FrontierMath (Tiers 1-3) | 91.2% | — |
| FrontierMath Tier 4 | 95% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| FrontierMath Erdős | 2.9% | — |

## Knowledge

- Claude Opus 5.5: 66.4 (#10)
- GPT-5.3 Chat: 38.8 (#140)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Expert | 1547 | 1397 |
| GPQA Diamond | 90.6% | — |
| SimpleQA Verified | 72.2% | — |

## Multimodal

- Claude Opus 5.5: 57.8 (#1)
- GPT-5.3 Chat: —

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Vision | 1321 | — |
| Blueprint-Bench 2 | 51.2% | — |
| Furniture Assembly | 83.3% | — |

## Multilingual

- Claude Opus 5.5: 59.1 (#2)
- GPT-5.3 Chat: 50.3 (#124)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Non-English | 1507 | 1382 |
| LMArena Chinese | 1588 | 1432 |
| LMArena French | 1514 | 1397 |
| LMArena Russian | 1520 | 1400 |
| LMArena Spanish | 1507 | 1371 |
| LMArena German | — | 1384 |
| LMArena Japanese | — | 1352 |
| LMArena Korean | — | 1346 |

## Instruction Following

- Claude Opus 5.5: 80.0 (#3)
- GPT-5.3 Chat: 72.8 (#129)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Instruction Following | 1537 | 1378 |

## Long Context

- Claude Opus 5.5: 47.1 (#19)
- GPT-5.3 Chat: 42.6 (#120)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Longer Query | 1532 | 1396 |

## Writing & Preference

- Claude Opus 5.5: 78.2 (#3)
- GPT-5.3 Chat: 63.1 (#68)

| Benchmark | Claude Opus 5.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Text | 1515 | 1389 |
| LMArena Creative Writing | 1533 | 1355 |
| EQ-Bench Creative Writing | 2050 | 1690 |
| LMArena Multi-Turn | 1499 | 1412 |

## FAQ

### Is Claude Opus 5.5 better than GPT-5.3 Chat?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 42.8 on the Noometry Index. GPT-5.3 Chat costs 1.7× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Opus 5.5 or GPT-5.3 Chat?

GPT-5.3 Chat is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

### Is Claude Opus 5.5 or GPT-5.3 Chat better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 41.4 in the Noometry coding category.

### Which has the bigger context window?

Claude Opus 5.5 does, with 1M tokens against 128K.

### How many benchmarks do Claude Opus 5.5 and GPT-5.3 Chat share?

15 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and GPT-5.3 Chat has 18.