Model comparison
GLM-5.3 vs GPT-5.5 Pro
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 54.8 on the Noometry Index. GLM-5.3 costs 31× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.
Last verified . 9 shared benchmarks.
Summary
- They share 9 benchmarks with published results for both. GLM-5.3 scores higher in 0 categories and GPT-5.5 Pro in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5.5 Pro leads 73.3 to 46.1.
- The biggest single-benchmark swing is FrontierMath Tier 4: 29.3% for GLM-5.3 and 78% for GPT-5.5 Pro.
- GLM-5.3 is cheaper at $1.40 / $4.40 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 1M.
- GLM-5.3 has downloadable open weights; the other is API-only.
Side by side
| GLM-5.3 | GPT-5.5 Pro | |
|---|---|---|
| Provider | Z.ai (Zhipu) | OpenAI |
| Noometry Index | 54.8 | 64.3 |
| Released | 2026-08-14 | 2026-04-23 |
| Weights | Open | Proprietary |
| Context window | 1M | 1.05M |
| Max output | 131K | 128K |
| Input $ / M tokens | $1.40 | $30 |
| Output $ / M tokens | $4.40 | $180 |
| Results tracked | 42 | 14 |
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Category by category
Coding Not comparable
GLM-5.3: 59.5 (#14), GPT-5.5 Pro: —
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| DeepSWE | 69% | — |
| FrontierCode | 40.1% | — |
| CursorBench | 42.6% | — |
| LMArena WebDev | 1622 | — |
| FrontierSWE | 30.2% | — |
| SciCode | 59% | — |
| WeirdML | 75.4% | — |
| LMArena Coding | 1496 | — |
| ALE-Bench | 1,317 | — |
Agentic & Tool Use Not comparable
GLM-5.3: 36.4 (#38), GPT-5.5 Pro: —
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| APEX-Agents | 56.6% | — |
| Vending-Bench 2 | 8,164 | — |
Reasoning GPT-5.5 Pro leads
GLM-5.3: 46.1 (#46), GPT-5.5 Pro: 73.3 (#10)
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| CritPt | 19.1% | 30.6% |
| Chess Puzzles | 21% | 64% |
| DTBench | 87.7% | 96% |
| LMCA | 55.5% | 53.9% |
| Epoch Capabilities Index | 155.61 | 162.07 |
| ARC-AGI-2 | — | 84.6% |
| SimpleBench | — | 76.9% |
| NYT Connections (extended) | 74.2% | — |
| ARC-AGI-1 | — | 96.5% |
| LMArena Hard Prompts | 1489 | — |
| Mystery Game Puzzles | 33% | — |
| Bench to the Future 3 | 0.15 | — |
Math GPT-5.5 Pro leads
GLM-5.3: 62.3 (#33), GPT-5.5 Pro: 84.0 (#10)
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | 68.8% | 87.7% |
| FrontierMath Tier 4 | 29.3% | 78% |
| OTIS Mock AIME 2024-2025 | 91.1% | 100% |
| ProofBench | 49% | — |
| LMArena Math | 1489 | — |
| FrontierMath (Feb 2025 set) | — | 52.4% |
| FrontierMath Tier 4 (v1) | — | 39.6% |
Knowledge GPT-5.5 Pro leads
GLM-5.3: 58.3 (#37), GPT-5.5 Pro: 64.1 (#19)
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| GPQA Diamond | 90.9% | 93.9% |
| SimpleQA Verified | 41% | — |
| LMArena Expert | 1516 | — |
Multilingual Not comparable
GLM-5.3: 55.7 (#28), GPT-5.5 Pro: —
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| LMArena Non-English | 1457 | — |
| LMArena Chinese | 1528 | — |
| LMArena French | 1499 | — |
| LMArena German | 1499 | — |
| LMArena Japanese | 1453 | — |
| LMArena Korean | 1472 | — |
| LMArena Russian | 1463 | — |
| LMArena Spanish | 1460 | — |
Instruction Following Not comparable
GLM-5.3: 77.5 (#23), GPT-5.5 Pro: —
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| LMArena Instruction Following | 1477 | — |
Long Context Not comparable
GLM-5.3: 45.4 (#41), GPT-5.5 Pro: —
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| LMArena Longer Query | 1482 | — |
Writing & Preference Not comparable
GLM-5.3: 75.7 (#6), GPT-5.5 Pro: —
| Benchmark | GLM-5.3 | GPT-5.5 Pro |
|---|---|---|
| LMArena Text | 1471 | — |
| LMArena Creative Writing | 1457 | — |
| EQ-Bench Creative Writing | 2075 | — |
| LMArena Multi-Turn | 1472 | — |
Frequently asked questions
Is GLM-5.3 better than GPT-5.5 Pro?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 54.8 on the Noometry Index. GLM-5.3 costs 31× 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-5.3 or GPT-5.5 Pro?
GLM-5.3 is cheaper. It lists at $1.40 per million input tokens and $4.40 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 1M.
How many benchmarks do GLM-5.3 and GPT-5.5 Pro share?
9 benchmarks have published results for both models. GLM-5.3 has 42 scored results on Noometry and GPT-5.5 Pro has 14.