# GPT-5.1-Codex vs Grok 4

> Side-by-side benchmark comparison for GPT-5.1-Codex and Grok 4 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

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

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-5.1-Codex and Grok 4 share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Grok 4 has the lower published output-token price.
- GPT-5.1-Codex has the larger published context window at 400K.

## Model Snapshot

| Property | GPT-5.1-Codex | Grok 4 |
|----------|----------|----------|
| Creator | OpenAI | xAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 400K | 128K |
| Independent public score (not head-to-head) | 51.62 | 54.91 |
| Benchmarks Covered | 3 | 4 |
| Pricing (input/output) | $1.25 / $10.00 | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 51.4 (Estimated · #54/151)
- Grok 4 public-lane score: Coming soon

| Benchmark | GPT-5.1-Codex | Grok 4 | Winner |
|-----------|-----------|-----------|--------|
| Gert Labs | 49.68% | 42.34% | GPT-5.1-Codex |
| JobBench | 26.2% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 47.4 (Estimated · #89/183)
- Grok 4 public-lane score: 53.4 (Estimated · #50/183)

| Benchmark | GPT-5.1-Codex | Grok 4 | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 13.12% | Coming soon | Coming soon |
| React Native Evals | Coming soon | 72.6% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 66.8 (Unranked · 1 rankable row)
- Grok 4 public-lane score: 61.3 (Unranked · 1 rankable row)

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 70.6 (Unranked · 2 rankable rows)
- Grok 4 public-lane score: 69.2 (Unranked · 2 rankable rows)

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 53.3 (Estimated · #69/181)
- Grok 4 public-lane score: 53.7 (Estimated · #66/181)

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 85.3 (#42/120)
- Grok 4 public-lane score: 64.1 (#67/120)

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: Coming soon
- Grok 4 public-lane score: 38.5 (Unranked · 2 rankable rows)

| Benchmark | GPT-5.1-Codex | Grok 4 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | Coming soon | 19.655% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 2.083% | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-5.1-Codex and Grok 4?

Not yet. The models share only 1 sourced benchmark row, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [GPT-5.1-Codex vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gpt-5-1-codex)
- [Grok 4 vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-grok-4)
- [GPT-5.1-Codex vs GPT-6 Astra](/compare/gpt-5-1-codex-vs-gpt-6-astra)
- [Grok 4 vs GPT-6 Astra](/compare/gpt-6-astra-vs-grok-4)

## Explore More

- [GPT-5.1-Codex profile](/models/gpt-5-1-codex)
- [Grok 4 profile](/models/grok-4)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)