# Claude Opus 5.5 vs GLM-5.3-Flash

> Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 49.6 on the Noometry Index. GLM-5.3-Flash costs 34× 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-glm-5-3-flash
- Last updated: 2026-10-10
- Shared benchmarks: 23

## Summary

- They share 23 benchmarks with published results for both. Claude Opus 5.5 scores higher in 10 categories and GLM-5.3-Flash in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 5.5 leads 79.5 to 31.7.
- The biggest single-benchmark swing is ProofBench: 100% for Claude Opus 5.5 and 21% for GLM-5.3-Flash.
- GLM-5.3-Flash is cheaper at $0.15 / $0.50 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
- GLM-5.3-Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| Provider | Anthropic | Z.ai (Zhipu) |
| Noometry Index | 68.5 | 49.6 |
| Rank | 3 | 45 |
| Context | 1M | 1M |
| Input $/M | $4 | $0.15 |
| Output $/M | $20 | $0.50 |
| Weights | Proprietary | Open |

## Coding

- Claude Opus 5.5: 71.4 (#1)
- GLM-5.3-Flash: 53.7 (#26)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| FrontierCode | 54.4% | 31.8% |
| LMArena WebDev | 1820 | 1614 |
| SciCode | 66.9% | 51.6% |
| LMArena Coding | 1545 | 1506 |
| DeepSWE | — | 63.4% |
| CursorBench | 57.8% | — |
| FrontierSWE | 62.3% | — |
| MirrorCode | 77.4% | — |
| ALE-Bench | — | 303.55 |

## Agentic & Tool Use

- Claude Opus 5.5: 45.3 (#13)
- GLM-5.3-Flash: 34.3 (#41)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| APEX-Agents | 73.5% | 52.8% |
| GDP.pdf | 30.6% | 14% |

## Reasoning

- Claude Opus 5.5: 79.5 (#2)
- GLM-5.3-Flash: 31.7 (#69)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| CritPt | 31.7% | 15.4% |
| LMArena Hard Prompts | 1545 | 1490 |
| Mystery Game Puzzles | 71% | 8% |
| ARC-AGI-2 | 92.5% | — |
| NYT Connections (extended) | 88.5% | — |
| ARC-AGI-1 | 97.5% | — |
| Chess Puzzles | — | 14% |
| EBR-Bench | 71.4% | — |
| DTBench | 98.9% | — |
| LMCA | 68.2% | — |
| Surface Evolver Bench | — | 52.5% |
| Bench to the Future 3 | — | 0.15 |
| Epoch Capabilities Index | — | 151.9 |

## Math

- Claude Opus 5.5: 92.4 (#2)
- GLM-5.3-Flash: 53.1 (#38)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| FrontierMath (Tiers 1-3) | 91.2% | 55.8% |
| FrontierMath Tier 4 | 95% | 17.1% |
| OTIS Mock AIME 2024-2025 | 100% | 93.9% |
| ProofBench | 100% | 21% |
| LMArena Math | — | 1499 |

## Knowledge

- Claude Opus 5.5: 66.6 (#9)
- GLM-5.3-Flash: 58.4 (#33)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| GPQA Diamond | 90.6% | 90.2% |
| LMArena Expert | 1564 | 1512 |
| SimpleQA Verified | 72.2% | — |

## Multimodal

- Claude Opus 5.5: 56.5 (#2)
- GLM-5.3-Flash: 42.6 (#25)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| LMArena Vision | — | 1304 |
| Furniture Assembly | 83.3% | — |

## Multilingual

- Claude Opus 5.5: 59.8 (#1)
- GLM-5.3-Flash: 56.2 (#24)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| LMArena Non-English | 1513 | 1462 |
| LMArena Chinese | 1572 | 1529 |
| LMArena Russian | 1532 | 1472 |
| LMArena French | — | 1495 |
| LMArena German | — | 1457 |
| LMArena Japanese | — | 1420 |
| LMArena Korean | — | 1443 |
| LMArena Spanish | — | 1471 |

## Instruction Following

- Claude Opus 5.5: 80.1 (#2)
- GLM-5.3-Flash: 77.8 (#17)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| LMArena Instruction Following | 1535 | 1480 |

## Long Context

- Claude Opus 5.5: 47.3 (#18)
- GLM-5.3-Flash: 45.3 (#41)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| LMArena Longer Query | 1540 | 1479 |

## Writing & Preference

- Claude Opus 5.5: 78.7 (#3)
- GLM-5.3-Flash: 65.4 (#49)

| Benchmark | Claude Opus 5.5 | GLM-5.3-Flash |
|---|---|---|
| LMArena Text | 1518 | 1471 |
| LMArena Creative Writing | 1538 | 1440 |
| LMArena Multi-Turn | 1520 | 1471 |
| EQ-Bench Creative Writing | 2050 | — |

## FAQ

### Is Claude Opus 5.5 better than GLM-5.3-Flash?

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 49.6 on the Noometry Index. GLM-5.3-Flash costs 34× 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 GLM-5.3-Flash?

GLM-5.3-Flash is cheaper. It lists at $0.15 per million input tokens and $0.50 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

### Is Claude Opus 5.5 or GLM-5.3-Flash better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.4 versus 53.7 in the Noometry coding category.

### Which has the bigger context window?

Both accept 1M tokens.

### How many benchmarks do Claude Opus 5.5 and GLM-5.3-Flash share?

23 benchmarks have published results for both models. Claude Opus 5.5 has 35 scored results on Noometry and GLM-5.3-Flash has 36.