# GPT-5.5 vs Grok 4.5

> Side-by-side benchmark comparison for GPT-5.5 and Grok 4.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-5-vs-grok-4-5
- Last updated: October 7, 2026

- Shared sourced benchmarks: 11
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick GPT-5.5 if you want the stronger benchmark profile. Grok 4.5 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- GPT-5.5 leads overall 67.79 to 63.97.
- The clearest category separation is in reasoning, where the averages are 66.7 for GPT-5.5 and 50.4 for Grok 4.5.
- The biggest single benchmark swing is ARC-AGI-2 in Reasoning, with scores of 85% and 52.6%.
- Grok 4.5 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- GPT-5.5 also has the larger context window at 1M.

## Model Snapshot

| Property | GPT-5.5 | Grok 4.5 |
|----------|----------|----------|
| Creator | OpenAI | xAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 500K |
| Overall Score | 67.79 | 63.97 |
| Benchmarks Covered | 41 | 17 |
| Pricing (input/output) | $5.00 / $30.00 | $2.00 / $6.00 |

## Category Breakdown

### Agentic

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 60.6 (Supported · #22/122)
- Grok 4.5 public-lane score: 57.6 (Supported · #29/122)

| Benchmark | GPT-5.5 | Grok 4.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 82% | Coming soon | Coming soon |
| CyberGym | 81.8% | Coming soon | Coming soon |
| BrowseComp | 84.4% | Coming soon | Coming soon |
| OSWorld-Verified | 78.7% | Coming soon | Coming soon |
| MCP Atlas | 75.3% | Coming soon | Coming soon |
| Toolathlon | 55.6% | Coming soon | Coming soon |
| τ²-bench results | 98% | Coming soon | Coming soon |
| Gert Labs | 72.93% | Coming soon | Coming soon |
| ResearchClawBench | 17.0% | Coming soon | Coming soon |
| OSWorld 2.0 | 13.0% | Coming soon | Coming soon |
| JobBench | 42.7% | Coming soon | Coming soon |
| ExploitGym | 13.4% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 76.4% | 67.8% | GPT-5.5 |
| ApprenticeBench | 20% | Coming soon | Coming soon |
| Terminal-Bench 3.0 | Coming soon | 15.7% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 83.3% | Coming soon |
| deepSwe | Coming soon | 53% | Coming soon |

### Coding

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 62.8 (Supported · #15/146)
- Grok 4.5 public-lane score: 57.7 (Supported · #27/146)

| Benchmark | GPT-5.5 | Grok 4.5 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | 58.6% | 64.7% | Grok 4.5 |
| Terminal-Bench 2.0 | 82.0% | Coming soon | Coming soon |
| Vibe Code Bench | 69.85% | Coming soon | Coming soon |
| React Native Evals | 84.7% | Coming soon | Coming soon |
| cursorBench31 | 59.2% | Coming soon | Coming soon |
| CursorBench 3.2 | 58.4% | 66.7% | Grok 4.5 |
| FrontierCode 1.1 Main | 43.0% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 85.3% | 87.4% | Grok 4.5 |
| SWE-bench (Vals) | 82.6% | 86.6% | Grok 4.5 |
| PostTrainBench v1.1 | 27.2% | 23.4% | GPT-5.5 |
| SWE Multilingual | Coming soon | 78% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 83.3% | Coming soon |
| VulcanBench v3 | Coming soon | 89.9% | Coming soon |

### Reasoning

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 66.7 (#18/28)
- Grok 4.5 public-lane score: 50.4 (#28/28)

| Benchmark | GPT-5.5 | Grok 4.5 | Winner |
|-----------|-----------|-----------|--------|
| MRCR v2 64K-128K | 83.1% | Coming soon | Coming soon |
| MRCR v2 128K-256K | 87.5% | Coming soon | Coming soon |
| ARC-AGI-2 | 85% | 52.6% | GPT-5.5 |
| ARC-AGI-3 | 0.4% | 0.3% | GPT-5.5 |
| ARC-AGI-1 | 95.00% | 85.67% | GPT-5.5 |

### Multimodal & Grounded

- Winner: Not comparable
- GPT-5.5 public-lane score: 71.4 (#19/49)
- Grok 4.5 public-lane score: 79.5 (Unranked · 1 rankable row)

| Benchmark | GPT-5.5 | Grok 4.5 | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | 81.2% | Coming soon | Coming soon |
| MMMU-Pro w/ Python | 83.2% | Coming soon | Coming soon |
| OfficeQA Pro | 54.1% | Coming soon | Coming soon |

### Knowledge

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 69.3 (Supported · #14/174)
- Grok 4.5 public-lane score: 67 (Supported · #19/174)

| Benchmark | GPT-5.5 | Grok 4.5 | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 93.6% | Coming soon | Coming soon |
| GPQA-D | 93.6% | Coming soon | Coming soon |
| HLE | 52.2% | Coming soon | Coming soon |
| HLE w/o tools | 41.4% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 93.2% | 92.9% | GPT-5.5 |
| MMLU-Pro (Vals) | 88.1% | 89.2% | Grok 4.5 |

### Instruction Following

- Winner: Not comparable
- GPT-5.5 public-lane score: 91.9 (#7/125)
- Grok 4.5 public-lane score: Coming soon

### Mathematics

- Winner: Not comparable
- GPT-5.5 public-lane score: 69.4 (Unranked · 3 rankable rows)
- Grok 4.5 public-lane score: Coming soon

| Benchmark | GPT-5.5 | Grok 4.5 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath (legacy) | 51.7% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 51.700% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 35.400% | Coming soon | Coming soon |

## FAQ

### Which is better overall, GPT-5.5 or Grok 4.5?

GPT-5.5 is ahead overall on BenchLM right now.

### Where is the biggest gap between GPT-5.5 and Grok 4.5?

The widest category gap is in reasoning, where the averages are 66.7 for GPT-5.5 and 50.4 for Grok 4.5.

### How many benchmarks does GPT-5.5 cover on BenchLM?

GPT-5.5 currently has 41 sourced benchmark scores on BenchLM.

### How many benchmarks does Grok 4.5 cover on BenchLM?

Grok 4.5 currently has 17 sourced benchmark scores on BenchLM.

## Related Comparisons

- [GPT-5.5 vs GPT-5.5 Pro](/compare/gpt-5-5-vs-gpt-5-5-pro)
- [Grok 4.5 vs GPT-5.5 Pro](/compare/gpt-5-5-pro-vs-grok-4-5)
- [GPT-5.5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-5-5)
- [Grok 4.5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-grok-4-5)

## Explore More

- [GPT-5.5 profile](/models/gpt-5-5)
- [Grok 4.5 profile](/models/grok-4-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)