# GLM-5.1 vs GPT-5.3 Codex

> Side-by-side benchmark comparison for GLM-5.1 and GPT-5.3 Codex across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/glm-5-1-vs-gpt-5-3-codex
- Last updated: September 23, 2026

- Shared sourced benchmarks: 7
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.6

## Quick Verdict

Pick GPT-5.3 Codex if you want the stronger benchmark profile. GLM-5.1 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- GPT-5.3 Codex leads overall 62.07 to 57.71.
- The clearest category separation is in knowledge, where the averages are 50.2 for GLM-5.1 and 64 for GPT-5.3 Codex.
- The biggest single benchmark swing is Vibe Code Bench in Coding, with scores of 31.46% and 61.77%.
- GLM-5.1 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.3 Codex also has the larger context window at 400K.

## Model Snapshot

| Property | GLM-5.1 | GPT-5.3 Codex |
|----------|----------|----------|
| Creator | Z.AI | OpenAI |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 203K | 400K |
| Overall Score | 57.71 | 62.07 |
| Benchmarks Covered | 26 | 10 |
| Pricing (input/output) | $1.40 / $4.40 | $1.75 / $14.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- GLM-5.1 public-lane score: 42.1 (Estimated · #43/105)
- GPT-5.3 Codex public-lane score: 54.8 (Estimated · #30/105)

| Benchmark | GLM-5.1 | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 63.5% | 77.3% | GPT-5.3 Codex |
| BrowseComp | 68% | Coming soon | Coming soon |
| τ³-bench results | 70.6% | Coming soon | Coming soon |
| MCP Atlas | 71.8% | Coming soon | Coming soon |
| CyberGym | 68.7% | Coming soon | Coming soon |
| Claw-Eval | 62.3% | Coming soon | Coming soon |
| Gert Labs | 60.11% | 57.47% | GLM-5.1 |
| ResearchClawBench | 18.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 56.9% | Coming soon | Coming soon |
| OSWorld-Verified | Coming soon | 64.7% | Coming soon |
| JobBench | Coming soon | 33.7% | Coming soon |

### Coding

- Winner: GPT-5.3 Codex
- GLM-5.1 public-lane score: 51.5 (Supported · #36/135)
- GPT-5.3 Codex public-lane score: 56.8 (Supported · #23/135)

| Benchmark | GLM-5.1 | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | 58.4% | 56.8% | GLM-5.1 |
| NL2Repo | 42.7% | Coming soon | Coming soon |
| SWE-Rebench | 62.7% | 58.2% | GLM-5.1 |
| Vibe Code Bench | 31.46% | 61.77% | GPT-5.3 Codex |
| OpenHarmony Bench | 52.3% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 81.4% | 87.3% | GPT-5.3 Codex |
| SWE-bench (Vals) | 76.4% | 78.0% | GPT-5.3 Codex |
| SWE-bench Verified | Coming soon | 85% | Coming soon |

### Reasoning

- Winner: Not comparable
- GLM-5.1 public-lane score: 71.7 (Unranked · 2 rankable rows)
- GPT-5.3 Codex public-lane score: 78.3 (Unranked · 2 rankable rows)

### Multimodal & Grounded

- Winner: Not comparable
- GLM-5.1 public-lane score: Coming soon
- GPT-5.3 Codex public-lane score: 75.7 (Unranked · 1 rankable row)

### Knowledge

- Winner: Directional only
- GLM-5.1 public-lane score: 50.2 (Supported · #54/160)
- GPT-5.3 Codex public-lane score: 64 (Estimated · #25/160)

| Benchmark | GLM-5.1 | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 86.2% | Coming soon | Coming soon |
| HLE | 52.3% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 84.5% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 86.9% | Coming soon | Coming soon |

### Instruction Following

- Winner: Directional only
- GLM-5.1 public-lane score: 92.4 (#4/124)
- GPT-5.3 Codex public-lane score: 91.2 (#14/124)

### Mathematics

- Winner: Not comparable
- GLM-5.1 public-lane score: 63.8 (#3/7)
- GPT-5.3 Codex public-lane score: Coming soon

| Benchmark | GLM-5.1 | GPT-5.3 Codex | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | 95.3% | Coming soon | Coming soon |
| HMMT Nov 2025 | 94.0% | Coming soon | Coming soon |
| HMMT Feb 2026 | 82.6% | Coming soon | Coming soon |
| MMAnswerBench | 83.8% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 33.448% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 12.500% | Coming soon | Coming soon |

## FAQ

### Which is better overall, GLM-5.1 or GPT-5.3 Codex?

GPT-5.3 Codex is ahead overall on BenchLM right now.

### Where is the biggest gap between GLM-5.1 and GPT-5.3 Codex?

The widest category gap is in knowledge, where the averages are 50.2 for GLM-5.1 and 64 for GPT-5.3 Codex.

### How many benchmarks does GLM-5.1 cover on BenchLM?

GLM-5.1 currently has 26 sourced benchmark scores on BenchLM.

### How many benchmarks does GPT-5.3 Codex cover on BenchLM?

GPT-5.3 Codex currently has 10 sourced benchmark scores on BenchLM.

## Related Comparisons

- [GLM-5.1 vs GLM-5.3](/compare/glm-5-1-vs-glm-5-3)
- [GPT-5.3 Codex vs GLM-5.3](/compare/glm-5-3-vs-gpt-5-3-codex)
- [GLM-5.1 vs GLM-5.2](/compare/glm-5-1-vs-glm-5-2)
- [GPT-5.3 Codex vs GLM-5.2](/compare/glm-5-2-vs-gpt-5-3-codex)

## Explore More

- [GLM-5.1 profile](/models/glm-5-1)
- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)