# GPT-5.1-Codex vs Grok Build 0.1

> GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 36.4 on the Noometry Index. Grok Build 0.1 costs 2.8× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-grok-build-0-1
- Last updated: 2026-10-12
- Shared benchmarks: 0

## Summary

- The widest gap is in agentic & tool use, where GPT-5.1-Codex leads 38.0 to 22.7.
- Grok Build 0.1 is cheaper at $1 / $2 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- GPT-5.1-Codex accepts more context: 400K tokens versus 256K.

## Snapshot

| | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 38.6 | 36.4 |
| Rank | 186 | 216 |
| Context | 400K | 256K |
| Input $/M | $1.25 | $1 |
| Output $/M | $10 | $2 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.9 (#116)
- Grok Build 0.1: 43.1 (#91)

| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| SciCode | — | 50.2% |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 38.0 (#33)
- Grok Build 0.1: 22.7 (#129)

| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| GBAEval | — | 2.4% |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Grok Build 0.1: 32.2 (#77)

| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| CritPt | — | 9.1% |

## Math

- GPT-5.1-Codex: 30.3 (#235)
- Grok Build 0.1: —

| Benchmark | GPT-5.1-Codex | Grok Build 0.1 |
|---|---|---|
| ProofBench | 9% | — |

## FAQ

### Is GPT-5.1-Codex better than Grok Build 0.1?

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 36.4 on the Noometry Index. Grok Build 0.1 costs 2.8× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.1-Codex or Grok Build 0.1?

Grok Build 0.1 is cheaper. It lists at $1 per million input tokens and $2 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

### Is GPT-5.1-Codex or Grok Build 0.1 better for coding?

Grok Build 0.1 scores higher on coding benchmarks: 43.1 versus 41.9 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.1-Codex does, with 400K tokens against 256K.

### How many benchmarks do GPT-5.1-Codex and Grok Build 0.1 share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Grok Build 0.1 has 3.