Model comparison
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.
Last verified . 0 shared benchmarks.
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.
Side by side
| GLM-4.5-Air | Mercury 2.5 | |
|---|---|---|
| Provider | Z.ai (Zhipu) | Inception |
| Noometry Index | 38.9 | 33.5 |
| Released | 2025-07-20 | 2026-09-08 |
| Weights | Open | Proprietary |
| Context window | 131K | 260K |
| Max output | 98K | 66K |
| Input $ / M tokens | $0.20 | $0.04 |
| Output $ / M tokens | $1.10 | $0.15 |
| Results tracked | 27 | 4 |
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Category by category
Coding Mercury 2.5 leads
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 leads
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 leads
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 Not comparable
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 Not comparable
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 Not comparable
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 Not comparable
GLM-4.5-Air: 41.6 (#135), Mercury 2.5: —
| Benchmark | GLM-4.5-Air | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1366 | — |
Writing & Preference Not comparable
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 | — |
Frequently asked questions
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.