# GPT-5.5 vs Grok 4.3

> Side-by-side benchmark comparison for GPT-5.5 and Grok 4.3 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-5-vs-grok-4-3
- Last updated: September 10, 2026

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

## Quick Verdict

Pick GPT-5.5 if you want the stronger benchmark profile. Grok 4.3 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 72.07 to 59.73.
- The clearest category separation is in agentic, where the averages are 61 for GPT-5.5 and 26.9 for Grok 4.3.
- The biggest single benchmark swing is Terminal-Bench 2.1 (Vals) in Agentic, with scores of 76.4% and 41.9%.
- Grok 4.3 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.

## Model Snapshot

| Property | GPT-5.5 | Grok 4.3 |
|----------|----------|----------|
| Creator | OpenAI | xAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 72.07 | 59.73 |
| Benchmarks Covered | 39 | 7 |
| Pricing (input/output) | $5.00 / $30.00 | $1.25 / $2.50 |

## Category Breakdown

### Agentic

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 61 (Supported · #17/152)
- Grok 4.3 public-lane score: 26.9 (Supported · #144/152)

| Benchmark | GPT-5.5 | Grok 4.3 | 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% | 43.86% | GPT-5.5 |
| ResearchClawBench | 17.0% | 12.4% | GPT-5.5 |
| 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% | 41.9% | GPT-5.5 |
| ApprenticeBench | 20% | Coming soon | Coming soon |

### Coding

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 67.6 (Supported · #7/151)
- Grok 4.3 public-lane score: 33.6 (Supported · #131/151)

| Benchmark | GPT-5.5 | Grok 4.3 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Pro | 58.6% | Coming soon | Coming soon |
| 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 |
| cursorBench32 | 58.4% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 43.0% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 85.3% | 84.5% | GPT-5.5 |
| SWE-bench (Vals) | 82.6% | 71.4% | GPT-5.5 |

### Multimodal & Grounded

- Winner: Coming soon
- GPT-5.5 public-lane score: 71.3 (#19/48)
- Grok 4.3 public-lane score: 65.6 (#25/48)

| Benchmark | GPT-5.5 | Grok 4.3 | 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 |

### Reasoning

- Winner: Coming soon
- GPT-5.5 public-lane score: 64 (#13/20)
- Grok 4.3 public-lane score: 65.2 (Unranked · 2 rankable rows)

| Benchmark | GPT-5.5 | Grok 4.3 | 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% | Coming soon | Coming soon |
| ARC-AGI-3 | 0.4% | Coming soon | Coming soon |

### Knowledge

- Winner: GPT-5.5
- GPT-5.5 public-lane score: 72.9 (Supported · #7/183)
- Grok 4.3 public-lane score: 57 (Supported · #44/183)

| Benchmark | GPT-5.5 | Grok 4.3 | 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% | 91.4% | GPT-5.5 |
| MMLU-Pro (Vals) | 88.1% | 85.8% | GPT-5.5 |

### Instruction Following

- Winner: Coming soon
- GPT-5.5 public-lane score: 93.2 (#7/123)
- Grok 4.3 public-lane score: 94.4 (#2/123)

### Mathematics

- Winner: Coming soon
- GPT-5.5 public-lane score: 69.6 (Unranked · 3 rankable rows)
- Grok 4.3 public-lane score: Coming soon

| Benchmark | GPT-5.5 | Grok 4.3 | 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 4.3?

GPT-5.5 is ahead overall on BenchLM right now.

### Where is the biggest gap between GPT-5.5 and Grok 4.3?

The widest category gap is in agentic, where the averages are 61 for GPT-5.5 and 26.9 for Grok 4.3.

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

GPT-5.5 currently has 39 sourced benchmark scores on BenchLM.

### How many benchmarks does Grok 4.3 cover on BenchLM?

Grok 4.3 currently has 7 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 4.3 vs GPT-5.5 Pro](/compare/gpt-5-5-pro-vs-grok-4-3)
- [GPT-5.5 vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gpt-5-5)
- [Grok 4.3 vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-grok-4-3)

## Explore More

- [GPT-5.5 profile](/models/gpt-5-5)
- [Grok 4.3 profile](/models/grok-4-3)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)