# GLM-5.1 vs Mercury 2.5

> GLM-5.1 is the stronger model overall, scoring 47.8 to 33.5 on the Noometry Index. Mercury 2.5 costs 32× less per token, which makes it the better buy when GLM-5.1's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/glm-5-1-vs-mercury-2-5
- Last updated: 2026-10-10
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. GLM-5.1 scores higher in 3 categories and Mercury 2.5 in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GLM-5.1 leads 49.7 to 23.3.
- The biggest single-benchmark swing is ProofBench: 22.2% for GLM-5.1 and 3% for Mercury 2.5.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $1.40 / $4.40 for GLM-5.1.
- Mercury 2.5 accepts more context: 260K tokens versus 200K.
- GLM-5.1 has downloadable open weights; the other is API-only.

## Snapshot

| | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| Provider | Z.ai (Zhipu) | Inception |
| Noometry Index | 47.8 | 33.5 |
| Rank | 59 | 242 |
| Context | 200K | 260K |
| Input $/M | $1.40 | $0.04 |
| Output $/M | $4.40 | $0.15 |
| Weights | Open | Proprietary |

## Coding

- GLM-5.1: 48.7 (#55)
- Mercury 2.5: 39.5 (#156)

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| SciCode | 43.8% | 38.5% |
| ALE-Bench | 887.1 | 301.65 |
| SWE-bench Verified | 74.2% | — |
| LMArena WebDev | 1508 | — |
| WeirdML | 57.1% | — |
| LMArena Coding | 1485 | — |

## Agentic & Tool Use

- GLM-5.1: 24.9 (#113)
- Mercury 2.5: —

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| APEX-Agents | 40.9% | — |
| ExploitBench | 18.1% | — |
| GBAEval | 0% | — |
| Vending-Bench 2 | 5,634 | — |

## Reasoning

- GLM-5.1: 39.1 (#60)
- Mercury 2.5: 22.4 (#193)

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| CritPt | 4.6% | 0% |
| SimpleBench | 55.1% | — |
| NYT Connections (extended) | 77.7% | — |
| Chess Puzzles | 19% | — |
| Thematic Generalization | 69.8% | — |
| LMArena Hard Prompts | 1472 | — |
| Epoch Capabilities Index | 149.84 | — |

## Math

- GLM-5.1: 49.7 (#60)
- Mercury 2.5: 23.3 (#272)

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| ProofBench | 22.2% | 3% |
| FrontierMath (Tiers 1-3) | 36.8% | — |
| MathArena Final-Answer Competitions | 67.1% | — |
| OTIS Mock AIME 2024-2025 | 93.3% | — |
| LMArena Math | 1473 | — |
| FrontierMath (Feb 2025 set) | 33.4% | — |
| FrontierMath Tier 4 (v1) | 12.5% | — |

## Knowledge

- GLM-5.1: 54.9 (#50)
- Mercury 2.5: —

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| GPQA Diamond | 89.9% | — |
| SimpleQA Verified | 34% | — |
| LMArena Expert | 1476 | — |

## Multilingual

- GLM-5.1: 55.0 (#36)
- Mercury 2.5: —

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1447 | — |
| LMArena Chinese | 1515 | — |
| LMArena French | 1474 | — |
| LMArena German | 1465 | — |
| LMArena Japanese | 1434 | — |
| LMArena Korean | 1418 | — |
| LMArena Russian | 1454 | — |
| LMArena Spanish | 1469 | — |

## Instruction Following

- GLM-5.1: 76.3 (#42)
- Mercury 2.5: —

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| LMArena Instruction Following | 1451 | — |

## Long Context

- GLM-5.1: 44.9 (#53)
- Mercury 2.5: —

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1466 | — |

## Writing & Preference

- GLM-5.1: 66.9 (#31)
- Mercury 2.5: —

| Benchmark | GLM-5.1 | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1461 | — |
| LMArena Creative Writing | 1453 | — |
| EQ-Bench Creative Writing | 1592 | — |
| LMArena Multi-Turn | 1472 | — |

## FAQ

### Is GLM-5.1 better than Mercury 2.5?

GLM-5.1 is the stronger model overall, scoring 47.8 to 33.5 on the Noometry Index. Mercury 2.5 costs 32× less per token, which makes it the better buy when GLM-5.1's lead doesn't matter for your workload.

### Which is cheaper, GLM-5.1 or Mercury 2.5?

Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; GLM-5.1 lists at $1.40 and $4.40.

### Is GLM-5.1 or Mercury 2.5 better for coding?

GLM-5.1 scores higher on coding benchmarks: 48.7 versus 39.5 in the Noometry coding category.

### Which has the bigger context window?

Mercury 2.5 does, with 260K tokens against 200K.

### How many benchmarks do GLM-5.1 and Mercury 2.5 share?

4 benchmarks have published results for both models. GLM-5.1 has 41 scored results on Noometry and Mercury 2.5 has 4.