# GLM-4.5-Air vs Mercury 2.5

> GLM-4.5-Air is the stronger model overall, scoring 38.9 to 33.5 on the Noometry Index. Mercury 2.5 costs 6.3× less per token, which makes it the better buy when GLM-4.5-Air's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/glm-4-5-air-vs-mercury-2-5
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in math, where GLM-4.5-Air leads 36.2 to 23.3.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $0.20 / $1.10 for GLM-4.5-Air.
- Mercury 2.5 accepts more context: 260K tokens versus 131K.
- GLM-4.5-Air has downloadable open weights; the other is API-only.

## Snapshot

| | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| Provider | Z.ai (Zhipu) | Inception |
| Noometry Index | 38.9 | 33.5 |
| Rank | 177 | 242 |
| Context | 131K | 260K |
| Input $/M | $0.20 | $0.04 |
| Output $/M | $1.10 | $0.15 |
| Weights | Open | Proprietary |

## Coding

- GLM-4.5-Air: 33.3 (#259)
- Mercury 2.5: 39.5 (#156)

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| SciCode | — | 38.5% |
| GSO | 2.9% | — |
| LMArena Coding | 1397 | — |
| ALE-Bench | — | 301.65 |

## Reasoning

- GLM-4.5-Air: 24.1 (#166)
- Mercury 2.5: 22.4 (#193)

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| Kagi LLM Benchmark | 43% | — |
| CritPt | — | 0% |
| LMArena Hard Prompts | 1379 | — |
| ForecastBench | 59.2 | — |

## Math

- GLM-4.5-Air: 36.2 (#170)
- Mercury 2.5: 23.3 (#272)

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| ProofBench | — | 3% |
| Omni-MATH | 39.1% | — |
| LMArena Math | 1396 | — |

## Knowledge

- GLM-4.5-Air: 35.0 (#191)
- Mercury 2.5: —

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| Humanity's Last Exam | 8.1% | — |
| MMLU-Pro | 76.2% | — |
| Vectara Hallucination Rate | 9.3% | — |
| GPQA (HELM) | 59.4% | — |
| LMArena Expert | 1370 | — |

## Multilingual

- GLM-4.5-Air: 49.1 (#135)
- Mercury 2.5: —

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1366 | — |
| LMArena Chinese | 1426 | — |
| LMArena French | 1399 | — |
| LMArena German | 1377 | — |
| LMArena Japanese | 1348 | — |
| LMArena Korean | 1308 | — |
| LMArena Russian | 1373 | — |
| LMArena Spanish | 1386 | — |

## Instruction Following

- GLM-4.5-Air: 69.6 (#171)
- Mercury 2.5: —

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| IFEval | 81.2% | — |
| LMArena Instruction Following | 1354 | — |

## Long Context

- GLM-4.5-Air: 41.6 (#135)
- Mercury 2.5: —

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1366 | — |

## Writing & Preference

- GLM-4.5-Air: 55.9 (#139)
- Mercury 2.5: —

| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1384 | — |
| LMArena Creative Writing | 1343 | — |
| WildBench | 78.9% | — |
| LMArena Multi-Turn | 1371 | — |

## FAQ

### Is GLM-4.5-Air better than Mercury 2.5?

GLM-4.5-Air is the stronger model overall, scoring 38.9 to 33.5 on the Noometry Index. Mercury 2.5 costs 6.3× less per token, which makes it the better buy when GLM-4.5-Air's lead doesn't matter for your workload.

### Which is cheaper, GLM-4.5-Air 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-4.5-Air lists at $0.20 and $1.10.

### Is GLM-4.5-Air or Mercury 2.5 better for coding?

Mercury 2.5 scores higher on coding benchmarks: 39.5 versus 33.3 in the Noometry coding category.

### Which has the bigger context window?

Mercury 2.5 does, with 260K tokens against 131K.

### How many benchmarks do GLM-4.5-Air and Mercury 2.5 share?

0 benchmarks have published results for both models. GLM-4.5-Air has 27 scored results on Noometry and Mercury 2.5 has 4.