# GPT-5.1-Codex vs Step 2 16k Exp 202412

> GPT-5.1-Codex and Step 2 16k Exp 202412 score almost the same on the Noometry Index (38.2 vs 38.6), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-step-2-16k-exp-202412
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in math, where Step 2 16k Exp 202412 leads 33.6 to 29.3.

## Snapshot

| | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 38.2 | 38.6 |
| Rank | 178 | 173 |
| Context | 400K | — |
| Input $/M | $1.25 | — |
| Output $/M | $10 | — |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.7 (#107)
- Step 2 16k Exp 202412: 37.9 (#170)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| LMArena Coding | — | 1316 |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 37.8 (#32)
- Step 2 16k Exp 202412: —

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Step 2 16k Exp 202412: 24.8 (#140)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Hard Prompts | — | 1299 |

## Math

- GPT-5.1-Codex: 29.3 (#218)
- Step 2 16k Exp 202412: 33.6 (#171)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| ProofBench | 9% | — |
| LMArena Math | — | 1305 |

## Knowledge

- GPT-5.1-Codex: —
- Step 2 16k Exp 202412: 34.6 (#187)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Expert | — | 1279 |

## Multilingual

- GPT-5.1-Codex: —
- Step 2 16k Exp 202412: 43.9 (#176)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Non-English | — | 1290 |
| LMArena Chinese | — | 1331 |
| LMArena Russian | — | 1324 |

## Instruction Following

- GPT-5.1-Codex: —
- Step 2 16k Exp 202412: 68.1 (#187)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Instruction Following | — | 1287 |

## Long Context

- GPT-5.1-Codex: —
- Step 2 16k Exp 202412: 39.7 (#165)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Longer Query | — | 1307 |

## Writing & Preference

- GPT-5.1-Codex: —
- Step 2 16k Exp 202412: 52.5 (#168)

| Benchmark | GPT-5.1-Codex | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Text | — | 1321 |
| LMArena Creative Writing | — | 1328 |
| LMArena Multi-Turn | — | 1292 |

## FAQ

### Is GPT-5.1-Codex better than Step 2 16k Exp 202412?

GPT-5.1-Codex and Step 2 16k Exp 202412 score almost the same on the Noometry Index (38.2 vs 38.6), so choose on price, context window or the category you care about most.

### Is GPT-5.1-Codex or Step 2 16k Exp 202412 better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.7 versus 37.9 in the Noometry coding category.

### How many benchmarks do GPT-5.1-Codex and Step 2 16k Exp 202412 share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Step 2 16k Exp 202412 has 12.