Model comparison
GLM-4.5 vs GPT-5.5 Pro
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 41.4 on the Noometry Index. GLM-4.5 costs 68× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in math, where GPT-5.5 Pro leads 83.8 to 36.3.
- GLM-4.5 is cheaper at $0.60 / $2.20 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 131K.
- GLM-4.5 has downloadable open weights; the other is API-only.
Side by side
| GLM-4.5 | GPT-5.5 Pro | |
|---|---|---|
| Provider | Z.ai (Zhipu) | OpenAI |
| Noometry Index | 41.4 | 64.3 |
| Released | 2025-07-27 | 2026-04-23 |
| Weights | Open | Proprietary |
| Context window | 131K | 1.05M |
| Max output | 98K | 128K |
| Input $ / M tokens | $0.60 | $30 |
| Output $ / M tokens | $2.20 | $180 |
| Results tracked | 27 | 14 |
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Category by category
Coding Not comparable
GLM-4.5: 41.1 (#121), GPT-5.5 Pro: —
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| SWE-bench Verified (bash only) | 54.2% | — |
| WeirdML | 40.6% | — |
| LMArena Coding | 1434 | — |
| ALE-Bench | 344.82 | — |
| AlgoTune | 1.52 | — |
Reasoning GPT-5.5 Pro leads
GLM-4.5: 27.7 (#99), GPT-5.5 Pro: 73.6 (#7)
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| ARC-AGI-2 | — | 84.6% |
| SimpleBench | — | 76.9% |
| Kagi LLM Benchmark | 57.9% | — |
| ARC-AGI-1 | — | 96.5% |
| CritPt | — | 30.6% |
| Chess Puzzles | — | 64% |
| LMArena Hard Prompts | 1430 | — |
| DTBench | — | 96% |
| LMCA | — | 53.9% |
| Epoch Capabilities Index | — | 162.45 |
Math GPT-5.5 Pro leads
GLM-4.5: 36.3 (#119), GPT-5.5 Pro: 83.8 (#8)
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 87.7% |
| FrontierMath Tier 4 | — | 78% |
| OTIS Mock AIME 2024-2025 | — | 100% |
| LMArena Math | 1427 | — |
| FrontierMath (Feb 2025 set) | — | 52.4% |
| FrontierMath Tier 4 (v1) | — | 39.6% |
Knowledge GPT-5.5 Pro leads
GLM-4.5: 35.5 (#172), GPT-5.5 Pro: 64.2 (#17)
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| GPQA Diamond | — | 93.9% |
| Humanity's Last Exam | 8.3% | — |
| Confabulations | 11.3% | — |
| LMArena Expert | 1433 | — |
Multilingual Not comparable
GLM-4.5: 53.0 (#74), GPT-5.5 Pro: —
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| LMArena Non-English | 1417 | — |
| LMArena Chinese | 1465 | — |
| LMArena French | 1423 | — |
| LMArena German | 1406 | — |
| LMArena Japanese | 1416 | — |
| LMArena Korean | 1382 | — |
| LMArena Russian | 1414 | — |
| LMArena Spanish | 1454 | — |
Instruction Following Not comparable
GLM-4.5: 74.3 (#100), GPT-5.5 Pro: —
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| LMArena Instruction Following | 1405 | — |
Long Context Not comparable
GLM-4.5: 38.2 (#196), GPT-5.5 Pro: —
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| Fiction.LiveBench | 58.3% | — |
| LMArena Longer Query | 1413 | — |
Writing & Preference Not comparable
GLM-4.5: 57.7 (#121), GPT-5.5 Pro: —
| Benchmark | GLM-4.5 | GPT-5.5 Pro |
|---|---|---|
| LMArena Text | 1430 | — |
| LMArena Creative Writing | 1395 | — |
| Short-Story Creative Writing | 73.4% | — |
| EQ-Bench Creative Writing | 1343 | — |
| LMArena Multi-Turn | 1415 | — |
Frequently asked questions
Is GLM-4.5 better than GPT-5.5 Pro?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 41.4 on the Noometry Index. GLM-4.5 costs 68× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Which is cheaper, GLM-4.5 or GPT-5.5 Pro?
GLM-4.5 is cheaper. It lists at $0.60 per million input tokens and $2.20 per million output tokens; GPT-5.5 Pro lists at $30 and $180.
Which has the bigger context window?
GPT-5.5 Pro does, with 1.05M tokens against 131K.
How many benchmarks do GLM-4.5 and GPT-5.5 Pro share?
0 benchmarks have published results for both models. GLM-4.5 has 27 scored results on Noometry and GPT-5.5 Pro has 14.