# Claude Sonnet 5.5 vs GLM-5.1

> Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 47.8 on the Noometry Index. GLM-5.1 costs 1.9× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-sonnet-5-5-vs-glm-5-1
- Last updated: 2026-10-12
- Shared benchmarks: 24

## Summary

- They share 24 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 8 categories and GLM-5.1 in 1 category; 7 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 49.7.
- The biggest single-benchmark swing is ProofBench: 100% for Claude Sonnet 5.5 and 22.2% for GLM-5.1.
- GLM-5.1 is cheaper at $1.40 / $4.40 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 200K.
- GLM-5.1 has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| Provider | Anthropic | Z.ai (Zhipu) |
| Noometry Index | 61.9 | 47.8 |
| Rank | 10 | 59 |
| Context | 1M | 200K |
| Input $/M | $2 | $1.40 |
| Output $/M | $10 | $4.40 |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 5.5: 67.3 (#6)
- GLM-5.1: 48.7 (#55)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| LMArena WebDev | 1774 | 1508 |
| SciCode | 61% | 43.8% |
| LMArena Coding | 1513 | 1485 |
| ALE-Bench | 1,819 | 887.1 |
| SWE-bench Verified | — | 74.2% |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| FrontierSWE | 61.9% | — |
| WeirdML | — | 57.1% |

## Agentic & Tool Use

- Claude Sonnet 5.5: 45.0 (#16)
- GLM-5.1: 24.9 (#113)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| APEX-Agents | 75.5% | 40.9% |
| ExploitBench | — | 18.1% |
| GBAEval | — | 0% |
| Vending-Bench 2 | — | 5,634 |

## Reasoning

- Claude Sonnet 5.5: 54.0 (#28)
- GLM-5.1: 39.1 (#60)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| NYT Connections (extended) | 80.5% | 77.7% |
| CritPt | 31.4% | 4.6% |
| LMArena Hard Prompts | 1495 | 1472 |
| Epoch Capabilities Index | 165.03 | 149.84 |
| SimpleBench | — | 55.1% |
| Chess Puzzles | — | 19% |
| Thematic Generalization | — | 69.8% |
| Mystery Game Puzzles | 65% | — |

## Math

- Claude Sonnet 5.5: 87.9 (#6)
- GLM-5.1: 49.7 (#60)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | 36.8% |
| OTIS Mock AIME 2024-2025 | 100% | 93.3% |
| ProofBench | 100% | 22.2% |
| LMArena Math | 1510 | 1473 |
| FrontierMath Tier 4 | 80.5% | — |
| MathArena Final-Answer Competitions | — | 67.1% |
| FrontierMath (Feb 2025 set) | — | 33.4% |
| FrontierMath Erdős | 2.9% | — |
| FrontierMath Tier 4 (v1) | — | 12.5% |

## Knowledge

- Claude Sonnet 5.5: 66.0 (#12)
- GLM-5.1: 54.9 (#50)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| GPQA Diamond | 95.6% | 89.9% |
| SimpleQA Verified | 46.5% | 34% |
| LMArena Expert | 1540 | 1476 |

## Multimodal

- Claude Sonnet 5.5: 51.5 (#6)
- GLM-5.1: —

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| LMArena Vision | 1289 | — |
| Furniture Assembly | 75% | — |

## Multilingual

- Claude Sonnet 5.5: 55.3 (#30)
- GLM-5.1: 55.0 (#36)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| LMArena Non-English | 1452 | 1447 |
| LMArena Chinese | 1522 | 1515 |
| LMArena Russian | 1451 | 1454 |
| LMArena French | — | 1474 |
| LMArena German | — | 1465 |
| LMArena Japanese | — | 1434 |
| LMArena Korean | — | 1418 |
| LMArena Spanish | — | 1469 |

## Instruction Following

- Claude Sonnet 5.5: 78.3 (#11)
- GLM-5.1: 76.3 (#42)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| LMArena Instruction Following | 1495 | 1451 |

## Long Context

- Claude Sonnet 5.5: 45.9 (#28)
- GLM-5.1: 44.9 (#53)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| LMArena Longer Query | 1498 | 1466 |

## Writing & Preference

- Claude Sonnet 5.5: 66.0 (#40)
- GLM-5.1: 66.9 (#31)

| Benchmark | Claude Sonnet 5.5 | GLM-5.1 |
|---|---|---|
| LMArena Text | 1471 | 1461 |
| LMArena Creative Writing | 1465 | 1453 |
| LMArena Multi-Turn | 1474 | 1472 |
| EQ-Bench Creative Writing | — | 1592 |

## FAQ

### Is Claude Sonnet 5.5 better than GLM-5.1?

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 47.8 on the Noometry Index. GLM-5.1 costs 1.9× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Sonnet 5.5 or GLM-5.1?

GLM-5.1 is cheaper. It lists at $1.40 per million input tokens and $4.40 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.

### Is Claude Sonnet 5.5 or GLM-5.1 better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 48.7 in the Noometry coding category.

### Which has the bigger context window?

Claude Sonnet 5.5 does, with 1M tokens against 200K.

### How many benchmarks do Claude Sonnet 5.5 and GLM-5.1 share?

24 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and GLM-5.1 has 41.