# GPT-5.1-Codex vs GPT-5.4 mini

> GPT-5.4 mini is the stronger model overall, scoring 45.0 to 38.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-gpt-5-4-mini
- Last updated: 2026-10-10
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. GPT-5.1-Codex scores higher in 1 category and GPT-5.4 mini in 2 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.4 mini leads 45.5 to 30.3.
- The biggest single-benchmark swing is ProofBench: 9% for GPT-5.1-Codex and 21% for GPT-5.4 mini.
- GPT-5.4 mini is cheaper at $0.75 / $4.50 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.

## Snapshot

| | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 38.6 | 45.0 |
| Rank | 186 | 76 |
| Context | 400K | 400K |
| Input $/M | $1.25 | $0.75 |
| Output $/M | $10 | $4.50 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.9 (#116)
- GPT-5.4 mini: 45.2 (#72)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| LMArena WebDev | 1337 | 1397 |
| ALE-Bench | 1,245 | 1,189 |
| FrontierCode | — | 27% |
| SWE-bench Verified (bash only) | 66% | — |
| SciCode | — | 49.9% |
| WeirdML | — | 60.3% |
| LMArena Coding | — | 1438 |

## Agentic & Tool Use

- GPT-5.1-Codex: 38.0 (#33)
- GPT-5.4 mini: 29.9 (#81)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| DeepResearch Bench | — | 36.3% |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- GPT-5.4 mini: 30.4 (#85)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| ARC-AGI-2 | — | 18.9% |
| Kagi LLM Benchmark | — | 37.9% |
| NYT Connections (extended) | — | 61.8% |
| ARC-AGI-1 | — | 63.7% |
| CritPt | — | 10% |
| Chess Puzzles | — | 24% |
| Thematic Generalization | — | 61.7% |
| LMArena Hard Prompts | — | 1424 |
| Mystery Game Puzzles | — | 11% |
| DTBench | — | 80% |
| LMCA | — | 40.8% |
| Epoch Capabilities Index | — | 148.84 |
| ForecastBench | — | 57 |

## Math

- GPT-5.1-Codex: 30.3 (#235)
- GPT-5.4 mini: 45.5 (#75)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| ProofBench | 9% | 21% |
| FrontierMath (Tiers 1-3) | — | 51.2% |
| FrontierMath Tier 4 | — | 9.8% |
| OTIS Mock AIME 2024-2025 | — | 88.9% |
| LMArena Math | — | 1419 |
| FrontierMath (Feb 2025 set) | — | 28.3% |
| FrontierMath Tier 4 (v1) | — | 2.1% |

## Knowledge

- GPT-5.1-Codex: —
- GPT-5.4 mini: 51.5 (#67)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| GPQA Diamond | — | 86.9% |
| SimpleQA Verified | — | 29.4% |
| Vectara Hallucination Rate | — | 5.5% |
| LMArena Expert | — | 1435 |

## Multimodal

- GPT-5.1-Codex: —
- GPT-5.4 mini: 39.7 (#56)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| LMArena Vision | — | 1245 |

## Multilingual

- GPT-5.1-Codex: —
- GPT-5.4 mini: 51.9 (#96)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| LMArena Non-English | — | 1405 |
| LMArena Chinese | — | 1446 |
| LMArena French | — | 1440 |
| LMArena German | — | 1409 |
| LMArena Japanese | — | 1374 |
| LMArena Korean | — | 1368 |
| LMArena Russian | — | 1417 |
| LMArena Spanish | — | 1405 |

## Instruction Following

- GPT-5.1-Codex: —
- GPT-5.4 mini: 74.1 (#102)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| LMArena Instruction Following | — | 1405 |

## Long Context

- GPT-5.1-Codex: —
- GPT-5.4 mini: 43.0 (#112)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| LMArena Longer Query | — | 1407 |

## Writing & Preference

- GPT-5.1-Codex: —
- GPT-5.4 mini: 64.0 (#58)

| Benchmark | GPT-5.1-Codex | GPT-5.4 mini |
|---|---|---|
| LMArena Text | — | 1412 |
| LMArena Creative Writing | — | 1370 |
| EQ-Bench Creative Writing | — | 1665 |
| LMArena Multi-Turn | — | 1429 |

## FAQ

### Is GPT-5.1-Codex better than GPT-5.4 mini?

GPT-5.4 mini is the stronger model overall, scoring 45.0 to 38.6 on the Noometry Index.

### Which is cheaper, GPT-5.1-Codex or GPT-5.4 mini?

GPT-5.4 mini is cheaper. It lists at $0.75 per million input tokens and $4.50 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

### Is GPT-5.1-Codex or GPT-5.4 mini better for coding?

GPT-5.4 mini scores higher on coding benchmarks: 45.2 versus 41.9 in the Noometry coding category.

### Which has the bigger context window?

Both accept 400K tokens.

### How many benchmarks do GPT-5.1-Codex and GPT-5.4 mini share?

3 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and GPT-5.4 mini has 46.