Model comparison
GLM-4.5-Air vs Mercury 2
GLM-4.5-Air and Mercury 2 score almost the same on the Noometry Index (38.9 vs 39.1), so choose on price, context window or the category you care about most.
Last verified . 12 shared benchmarks.
Summary
- They share 12 benchmarks with published results for both. GLM-4.5-Air scores higher in 4 categories and Mercury 2 in 3 categories; 4 gaps are clear of the uncertainty.
- Mercury 2 is cheaper at $0.25 / $0.75 per million input/output tokens, against $0.20 / $1.10 for GLM-4.5-Air.
- GLM-4.5-Air accepts more context: 131K tokens versus 128K.
- GLM-4.5-Air has downloadable open weights; the other is API-only.
Side by side
| GLM-4.5-Air | Mercury 2 | |
|---|---|---|
| Provider | Z.ai (Zhipu) | Inception |
| Noometry Index | 38.9 | 39.1 |
| Released | 2025-07-20 | 2026-02-20 |
| Weights | Open | Proprietary |
| Context window | 131K | 128K |
| Max output | 98K | 50K |
| Input $ / M tokens | $0.20 | $0.25 |
| Output $ / M tokens | $1.10 | $0.75 |
| Results tracked | 27 | 17 |
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Category by category
Coding Too close to call
GLM-4.5-Air: 33.3 (#259), Mercury 2: 33.5 (#255)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| LMArena Coding | 1397 | 1391 |
| LMArena WebDev | — | 1171 |
| SciCode | — | 38.7% |
| GSO | 2.9% | — |
| WeirdML | — | 43.2% |
| ALE-Bench | — | 785.58 |
Reasoning Too close to call
GLM-4.5-Air: 24.1 (#166), Mercury 2: 23.8 (#170)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| LMArena Hard Prompts | 1379 | 1362 |
| Kagi LLM Benchmark | 43% | — |
| CritPt | — | 0.8% |
| ForecastBench | 59.2 | — |
Math Not comparable
GLM-4.5-Air: 36.2 (#170), Mercury 2: —
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| Omni-MATH | 39.1% | — |
| LMArena Math | 1396 | — |
Knowledge Mercury 2 leads
GLM-4.5-Air: 35.0 (#191), Mercury 2: 36.2 (#172)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| Vectara Hallucination Rate | 9.3% | 12.3% |
| LMArena Expert | 1370 | 1358 |
| Humanity's Last Exam | 8.1% | — |
| MMLU-Pro | 76.2% | — |
| GPQA (HELM) | 59.4% | — |
Multilingual GLM-4.5-Air leads
GLM-4.5-Air: 49.1 (#135), Mercury 2: 46.6 (#157)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| LMArena Non-English | 1366 | 1331 |
| LMArena Chinese | 1426 | 1417 |
| LMArena Russian | 1373 | 1304 |
| LMArena French | 1399 | — |
| LMArena German | 1377 | — |
| LMArena Japanese | 1348 | — |
| LMArena Korean | 1308 | — |
| LMArena Spanish | 1386 | — |
Instruction Following Too close to call
GLM-4.5-Air: 69.6 (#171), Mercury 2: 70.2 (#165)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| LMArena Instruction Following | 1354 | 1329 |
| IFEval | 81.2% | — |
Long Context GLM-4.5-Air leads
GLM-4.5-Air: 41.6 (#135), Mercury 2: 40.5 (#154)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| LMArena Longer Query | 1366 | 1330 |
Writing & Preference GLM-4.5-Air leads
GLM-4.5-Air: 55.9 (#139), Mercury 2: 53.8 (#155)
| Benchmark | GLM-4.5-Air | Mercury 2 |
|---|---|---|
| LMArena Text | 1384 | 1355 |
| LMArena Creative Writing | 1343 | 1289 |
| LMArena Multi-Turn | 1371 | 1358 |
| WildBench | 78.9% | — |
Frequently asked questions
Is GLM-4.5-Air better than Mercury 2?
GLM-4.5-Air and Mercury 2 score almost the same on the Noometry Index (38.9 vs 39.1), so choose on price, context window or the category you care about most.
Which is cheaper, GLM-4.5-Air or Mercury 2?
Mercury 2 is cheaper. It lists at $0.25 per million input tokens and $0.75 per million output tokens; GLM-4.5-Air lists at $0.20 and $1.10.
Is GLM-4.5-Air or Mercury 2 better for coding?
They score almost the same on coding (33.3 vs 33.5); test both on your own repository before choosing.
Which has the bigger context window?
GLM-4.5-Air does, with 131K tokens against 128K.
How many benchmarks do GLM-4.5-Air and Mercury 2 share?
12 benchmarks have published results for both models. GLM-4.5-Air has 27 scored results on Noometry and Mercury 2 has 17.