Model comparison
GLM-4.5-Air vs gpt-oss-120b
GLM-4.5-Air is the stronger model overall, scoring 38.9 to 36.3 on the Noometry Index. gpt-oss-120b costs 6.0× less per token, which makes it the better buy when GLM-4.5-Air's lead doesn't matter for your workload.
Last verified . 24 shared benchmarks.
Summary
- They share 24 benchmarks with published results for both. GLM-4.5-Air scores higher in 5 categories and gpt-oss-120b in 3 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in math, where gpt-oss-120b leads 52.5 to 36.2.
- The biggest single-benchmark swing is Omni-MATH: 39.1% for GLM-4.5-Air and 68.8% for gpt-oss-120b.
- gpt-oss-120b is cheaper at $0.037 / $0.17 per million input/output tokens, against $0.20 / $1.10 for GLM-4.5-Air.
Side by side
| GLM-4.5-Air | gpt-oss-120b | |
|---|---|---|
| Provider | Z.ai (Zhipu) | OpenAI |
| Noometry Index | 38.9 | 36.3 |
| Released | 2025-07-20 | 2025-08-05 |
| Weights | Open | Open |
| Context window | 131K | 131K |
| Max output | 98K | 41K |
| Input $ / M tokens | $0.20 | $0.037 |
| Output $ / M tokens | $1.10 | $0.17 |
| Results tracked | 27 | 48 |
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Category by category
Coding Too close to call
GLM-4.5-Air: 33.3 (#259), gpt-oss-120b: 33.5 (#256)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| LMArena Coding | 1397 | 1380 |
| SWE-bench Verified (bash only) | — | 26% |
| Aider Polyglot | — | 41.8% |
| SciCode | — | 36% |
| GSO | 2.9% | — |
| WeirdML | — | 48.2% |
| ALE-Bench | — | 575.62 |
| AlgoTune | — | 1.41 |
Agentic & Tool Use Not comparable
GLM-4.5-Air: —, gpt-oss-120b: 12.2 (#153)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| Terminal-Bench | — | 18.7% |
| APEX-Agents | — | 4.4% |
| METR Time Horizons | — | 56.6% |
| Vending-Bench 2 | — | -21.53 |
Reasoning GLM-4.5-Air leads
GLM-4.5-Air: 24.1 (#166), gpt-oss-120b: 20.0 (#245)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| Kagi LLM Benchmark | 43% | 58.6% |
| LMArena Hard Prompts | 1379 | 1364 |
| SimpleBench | — | 22.1% |
| CritPt | — | 1.1% |
| Chess Puzzles | — | 20% |
| Mystery Game Puzzles | — | 2% |
| DTBench | — | 76.3% |
| LMCA | — | 22.1% |
| Surface Evolver Bench | — | 25% |
| Epoch Capabilities Index | — | 139.93 |
| ForecastBench | 59.2 | — |
Math gpt-oss-120b leads
GLM-4.5-Air: 36.2 (#170), gpt-oss-120b: 52.5 (#50)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| Omni-MATH | 39.1% | 68.8% |
| LMArena Math | 1396 | 1389 |
| OTIS Mock AIME 2024-2025 | — | 88.9% |
Knowledge gpt-oss-120b leads
GLM-4.5-Air: 35.0 (#191), gpt-oss-120b: 42.4 (#96)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| MMLU-Pro | 76.2% | 79.5% |
| Vectara Hallucination Rate | 9.3% | 14.2% |
| GPQA (HELM) | 59.4% | 68.4% |
| LMArena Expert | 1370 | 1356 |
| GPQA Diamond | — | 75.8% |
| Humanity's Last Exam | 8.1% | — |
| Confabulations | — | 15.7% |
Multilingual GLM-4.5-Air leads
GLM-4.5-Air: 49.1 (#135), gpt-oss-120b: 48.0 (#147)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| LMArena Non-English | 1366 | 1351 |
| LMArena Chinese | 1426 | 1385 |
| LMArena French | 1399 | 1369 |
| LMArena German | 1377 | 1353 |
| LMArena Japanese | 1348 | 1331 |
| LMArena Korean | 1308 | 1282 |
| LMArena Russian | 1373 | 1343 |
| LMArena Spanish | 1386 | 1389 |
Instruction Following Too close to call
GLM-4.5-Air: 69.6 (#171), gpt-oss-120b: 69.3 (#173)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| IFEval | 81.2% | 83.6% |
| LMArena Instruction Following | 1354 | 1318 |
Long Context GLM-4.5-Air leads
GLM-4.5-Air: 41.6 (#135), gpt-oss-120b: 31.4 (#278)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| LMArena Longer Query | 1366 | 1319 |
| Fiction.LiveBench | — | 44.4% |
Writing & Preference GLM-4.5-Air leads
GLM-4.5-Air: 55.9 (#139), gpt-oss-120b: 46.5 (#217)
| Benchmark | GLM-4.5-Air | gpt-oss-120b |
|---|---|---|
| LMArena Text | 1384 | 1365 |
| LMArena Creative Writing | 1343 | 1275 |
| WildBench | 78.9% | 84.5% |
| LMArena Multi-Turn | 1371 | 1340 |
| Short-Story Creative Writing | — | 77.1% |
| EQ-Bench Creative Writing | — | 961 |
Frequently asked questions
Is GLM-4.5-Air better than gpt-oss-120b?
GLM-4.5-Air is the stronger model overall, scoring 38.9 to 36.3 on the Noometry Index. gpt-oss-120b costs 6.0× 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 gpt-oss-120b?
gpt-oss-120b is cheaper. It lists at $0.037 per million input tokens and $0.17 per million output tokens; GLM-4.5-Air lists at $0.20 and $1.10.
Is GLM-4.5-Air or gpt-oss-120b 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?
Both accept 131K tokens.
How many benchmarks do GLM-4.5-Air and gpt-oss-120b share?
24 benchmarks have published results for both models. GLM-4.5-Air has 27 scored results on Noometry and gpt-oss-120b has 48.