GLM 5.3 vs GPT-5.3-Codex
GLM 5.3 
GPT-5.3-Codex Verdict
- GLM 5.3 (max) and GPT-5.3-Codex are level on quality (60.0 vs 60.6).
- GLM 5.3 (max) is stronger in coding, human preference, maths, reasoning.
- GPT-5.3-Codex is stronger in agents & tools, knowledge, composite, instruction following, long context, multimodal.
- GLM 5.3 (max) is 2.2× cheaper ($2.15 vs $4.81 per 1M blended).
- GPT-5.3-Codex streams 1.9× faster (124 vs 66 tokens per second).
| Metric | GLM 5.3 (max) | GPT-5.3-Codex |
|---|---|---|
| BenchLeader Index | 60.0 | 60.6 |
| Agents & tools score | 52.8 | 61.7 |
| Coding score | 64.3 | 54.7 |
| Human preference score | 68.9 | – |
| Knowledge score | 55.8 | 65.9 |
| Maths score | 60.0 | – |
| Reasoning score | 66.9 | – |
| Composite score | – | 64.0 |
| Instruction following score | – | 70.1 |
| Long context score | – | 66.0 |
| Multimodal score | – | 61.6 |
| Blended price $/M | $2.15 | $4.81 |
| Output speed | 66 tok/s | 124 tok/s |
| Time to first answer | 33.5 s | 48.3 s |
| Context window | 1M | 400k |
| GPQA Diamond | 90.9% | – |
| FrontierMath Tiers 1–3 | 68.8% | – |
| FrontierMath Tier 4 | 29.3% | – |
| OTIS Mock AIME | 91.1% | – |
| SimpleQA Verified | 41.0% | – |
| Terminal-Bench | 41.8% | 78.4% |
| SciCode | 56.5% | – |
| WeirdML | 75.4% | 79.3% |
| APEX-Agents | – | 31.8% |
| ProofBench | 49.0% | – |
| Epoch Capabilities Index | – | 156.6 |
| LMArena Text | 1486 | – |
| LMArena Hard Prompts | 1509 | – |
| LMArena Coding | 1526 | – |
| LMArena WebDev | 1614 | 1409 |
| LMArena Agent | 2.6 | – |
| AA Intelligence Index | – | 32.5 |
| IFBench | – | 75.4% |
| AA-LCR | – | 83.3% |
| MMMU-Pro | – | 78.5% |
| AA-Omniscience | – | 10.9 |
| Terminal-Bench Hard | – | 53.0% |
| GPQA Diamond (AA) | – | 91.5% |
| Humanity's Last Exam (AA) | – | 42.5% |
| τ²-Bench Telecom (AA) | – | 86.0% |
| LiveCodeBench | 80.5% | – |
| MMLU-Pro | 86.8% | – |
| IOI | 68.4% | – |
| LegalBench | 84.8% | – |
| TaxEval | 72.4% | – |
| Terminal-Bench 2.1 (Vals) | 71.5% | – |
| SWE-bench (Vals) | 95.4% | – |
| GPQA Diamond (Vals) | 88.1% | – |
| Vals Index | 57.0 | – |
| HiL-Bench | – | 4.3% |
Data as of 2026-09-13. Best configuration of each model; every score links to its source on the model pages.
GLM 5.3 vs GPT-5.3-Codex: questions
- Is GLM 5.3 better than GPT-5.3-Codex?
- GLM 5.3 (max) and GPT-5.3-Codex are level on quality (60.0 vs 60.6). The BenchLeader Index combines every independent quality benchmark; GPT-5.3-Codex is ahead overall as of 2026-09-13, but check the category scores for your use.
- Is GLM 5.3 better than GPT-5.3-Codex for coding?
- GLM 5.3 scores higher in coding (64 vs 55 on the category index, where 50 is average).
- Is GLM 5.3 better than GPT-5.3-Codex for agentic tasks?
- GPT-5.3-Codex scores higher in agentic tasks (62 vs 53 on the category index, where 50 is average).
- Which is cheaper, GLM 5.3 or GPT-5.3-Codex?
- GLM 5.3 is cheaper: $2.15 against $4.81 per million tokens, blended at three input tokens per output token.
- Which is faster, GLM 5.3 or GPT-5.3-Codex?
- GPT-5.3-Codex streams faster: 124 against 66 output tokens per second.
- Which has the larger context window?
- GLM 5.3 accepts more context: 1M against 400k tokens.