# GLM-5.1 vs GPT-5.5 Pro

> Side-by-side benchmark comparison for GLM-5.1 and GPT-5.5 Pro across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/glm-5-1-vs-gpt-5-5-pro
- Last updated: September 4, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Pick GLM-5.1 if you want the stronger benchmark profile. GPT-5.5 Pro only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- GLM-5.1 leads overall 64.41 to 63.07.
- The clearest category separation is in agentic, where the averages are 50.1 for GLM-5.1 and 60.6 for GPT-5.5 Pro.
- The biggest single benchmark swing is FrontierMath v2 (Tier 4) in Mathematics, with scores of 12.500% and 39.600%.
- GLM-5.1 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.5 Pro also has the larger context window at 1M.

## Model Snapshot

| Property | GLM-5.1 | GPT-5.5 Pro |
|----------|----------|----------|
| Creator | Z.AI | OpenAI |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 203K | 1M |
| Overall Score | 64.41 | 63.07 |
| Benchmarks Covered | 26 | 6 |
| Pricing (input/output) | $1.40 / $4.40 | $30.00 / $180.00 |

## Category Breakdown

### Agentic

- Winner: Coming soon
- GLM-5.1 public-lane score: 50.1 (Estimated · #63/151)
- GPT-5.5 Pro public-lane score: 60.6 (Estimated · #24/151)

| Benchmark | GLM-5.1 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 63.5% | Coming soon | Coming soon |
| BrowseComp | 68% | 90.1% | GPT-5.5 Pro |
| 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% | Coming soon | Coming soon |
| ResearchClawBench | 18.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 56.9% | Coming soon | Coming soon |

### Coding

- Winner: Coming soon
- GLM-5.1 public-lane score: 56.8 (Supported · #39/183)
- GPT-5.5 Pro public-lane score: Coming soon

| Benchmark | GLM-5.1 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | 58.4% | Coming soon | Coming soon |
| NL2Repo | 42.7% | Coming soon | Coming soon |
| SWE-Rebench | 62.7% | Coming soon | Coming soon |
| Vibe Code Bench | 31.46% | Coming soon | Coming soon |
| OpenHarmony Bench | 52.3% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 81.4% | Coming soon | Coming soon |
| SWE-bench (Vals) | 76.4% | Coming soon | Coming soon |

### Reasoning

- Winner: Coming soon
- GLM-5.1 public-lane score: 69.9 (Unranked · 2 rankable rows)
- GPT-5.5 Pro public-lane score: Coming soon

### Knowledge

- Winner: Coming soon
- GLM-5.1 public-lane score: 55.4 (Supported · #59/181)
- GPT-5.5 Pro public-lane score: 61.1 (Estimated · #36/181)

| Benchmark | GLM-5.1 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 86.2% | Coming soon | Coming soon |
| HLE | 52.3% | 57.2% | GPT-5.5 Pro |
| GPQA Diamond (Vals) | 84.5% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 86.9% | Coming soon | Coming soon |
| HLE w/o tools | Coming soon | 43.1% | Coming soon |

### Instruction Following

- Winner: Coming soon
- GLM-5.1 public-lane score: 93.5 (#5/120)
- GPT-5.5 Pro public-lane score: Coming soon

### Mathematics

- Winner: Coming soon
- GLM-5.1 public-lane score: 64.1 (#3/7)
- GPT-5.5 Pro public-lane score: 70.2 (Unranked · 3 rankable rows)

| Benchmark | GLM-5.1 | GPT-5.5 Pro | 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% | 51.000% | GPT-5.5 Pro |
| FrontierMath v2 (Tier 4) | 12.500% | 39.600% | GPT-5.5 Pro |
| FrontierMath (legacy) | Coming soon | 52.4% | Coming soon |

## FAQ

### Which is better overall, GLM-5.1 or GPT-5.5 Pro?

GLM-5.1 is ahead overall on BenchLM right now.

### Where is the biggest gap between GLM-5.1 and GPT-5.5 Pro?

The widest category gap is in agentic, where the averages are 50.1 for GLM-5.1 and 60.6 for GPT-5.5 Pro.

### 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-5.5 Pro cover on BenchLM?

GPT-5.5 Pro currently has 6 sourced benchmark scores on BenchLM.

## Related Comparisons

- [GLM-5.1 vs GLM-5.3](/compare/glm-5-1-vs-glm-5-3)
- [GPT-5.5 Pro vs GLM-5.3](/compare/glm-5-3-vs-gpt-5-5-pro)
- [GLM-5.1 vs GLM-5.2](/compare/glm-5-1-vs-glm-5-2)
- [GPT-5.5 Pro vs GLM-5.2](/compare/glm-5-2-vs-gpt-5-5-pro)

## Explore More

- [GLM-5.1 profile](/models/glm-5-1)
- [GPT-5.5 Pro profile](/models/gpt-5-5-pro)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)