Claude Opus 5.5 vs GLM 5.3 Flash
Claude Opus 5.5 
GLM 5.3 Flash Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 63.6.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- GLM 5.3 Flash is stronger in agents & tools, coding, human preference, maths.
- GLM 5.3 Flash is 34× cheaper ($0.238 vs $8.00 per 1M blended).
- GLM 5.3 Flash streams 1.4× faster (66 vs 48 tokens per second).
| Metric | Claude Opus 5.5 (thinking) | GLM 5.3 Flash |
|---|---|---|
| BenchLeader Index | 70.7 | 63.6 |
| Composite score | 95.0 | 60.6 |
| Knowledge score | 85.0 | 66.8 |
| Long context score | 68.5 | 66.1 |
| Multimodal score | 71.9 | 65.3 |
| Reasoning score | 95.0 | 69.2 |
| Agents & tools score | – | 64.3 |
| Coding score | – | 65.7 |
| Human preference score | – | 67.6 |
| Maths score | – | 71.1 |
| Blended price $/M | $8.00 | $0.238 |
| Output speed | 48 tok/s | 66 tok/s |
| Time to first answer | 4.2 s | 33.3 s |
| Context window | 1M | 1M |
| SciCode | – | 51.6% |
| APEX-Agents | – | 52.8% |
| Epoch Capabilities Index | – | 151.9 |
| LMArena Text | – | 1475 |
| LMArena Hard Prompts | – | 1498 |
| LMArena Coding | – | 1525 |
| LMArena WebDev | – | 1607 |
| LMArena Vision | – | 1299 |
| LMArena Agent | – | 1.1 |
| LiveBench | – | 71.6% |
| LiveBench Reasoning | – | 77.6% |
| LiveBench Coding | – | 79.0% |
| LiveBench Agentic Coding | – | 56.8% |
| LiveBench Mathematics | – | 81.2% |
| LiveBench Data Analysis | – | 76.4% |
| LiveBench Language | – | 77.3% |
| LiveBench Instruction Following | – | 52.8% |
| AA Intelligence Index | 57.6 | 41.8 |
| AA-LCR | 84.7% | 80.0% |
| MMMU-Pro | 87.7% | – |
| AA-Omniscience | 46.4 | 7.5 |
| GPQA Diamond (AA) | – | 91.2% |
| Humanity's Last Exam (AA) | 61.4% | 39.9% |
| SciCode (AA) | 66.9% | 51.6% |
| CritPt | 31.7% | 15.4% |
| GDPval (AA) | 67.3% | 57.0% |
| τ²-Bench Banking (AA) | – | 47.2% |
| LMArena Maths | – | 1513 |
| LMArena Creative Writing | – | 1435 |
| LMArena Instruction Following | – | 1471 |
| LMArena Multi-turn | – | 1475 |
| LMArena Longer Queries | – | 1476 |
| BTF-3 | – | 14.9% |
| Terminal-Bench 4.0 (AA) | 59.6% | 32.8% |
| Terminal-Bench 2.1 (AA) | – | 84.3% |
| AutomationBench | 69.5% | 60.4% |
| GDP.pdf | 26.2% | 15.4% |
| MLCR | – | 51.1% |
| Harvey LAB | 91.2% | – |
| EnterpriseOps-Gym | – | 33.2% |
| AA-Omniscience: accuracy | 66.2% | 27.5% |
| AA-Omniscience: non-hallucination | 41.4% | 72.4% |
| AA-Briefcase | 1822 | 1459 |
| AA Openness Index | – | 44.4 |
Data as of 2026-09-22. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 5.5 vs GLM 5.3 Flash: questions
- Is Claude Opus 5.5 better than GLM 5.3 Flash?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 63.6. The BenchLeader Index combines every independent quality benchmark; Claude Opus 5.5 (thinking) is ahead overall as of 2026-09-22, but check the category scores for your use.
- Which is cheaper, Claude Opus 5.5 or GLM 5.3 Flash?
- GLM 5.3 Flash is cheaper: $0.238 against $8.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 5.5 or GLM 5.3 Flash?
- GLM 5.3 Flash streams faster: 66 against 48 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.