# GPT-5.2 Codex vs Step 3.5 Flash

> GPT-5.2 Codex and Step 3.5 Flash score almost the same on the Noometry Index (42.6 vs 42.3), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/gpt-5-2-codex-vs-step-3-5-flash
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.2 Codex leads 45.5 to 42.4.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $1.75 / $14 for GPT-5.2 Codex.
- GPT-5.2 Codex accepts more context: 400K tokens versus 256K.
- Step 3.5 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 42.6 | 42.3 |
| Rank | 111 | 116 |
| Context | 400K | 256K |
| Input $/M | $1.75 | $0.10 |
| Output $/M | $14 | $0.30 |
| Weights | Proprietary | Open |

## Coding

- GPT-5.2 Codex: 45.5 (#71)
- Step 3.5 Flash: 42.4 (#105)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| SWE-bench Verified (bash only) | 72.8% | — |
| LMArena WebDev | 1339 | — |
| SWE-bench Multilingual | 66.3% | — |
| LMArena Coding | — | 1436 |
| ALE-Bench | 1,300 | — |

## Agentic & Tool Use

- GPT-5.2 Codex: 41.0 (#22)
- Step 3.5 Flash: —

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| Terminal-Bench | 66.5% | — |

## Reasoning

- GPT-5.2 Codex: —
- Step 3.5 Flash: 22.2 (#202)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| NYT Connections (extended) | — | 28.4% |
| LMArena Hard Prompts | — | 1411 |

## Math

- GPT-5.2 Codex: —
- Step 3.5 Flash: 42.6 (#84)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| MathArena Final-Answer Competitions | — | 66.8% |
| LMArena Math | — | 1408 |

## Knowledge

- GPT-5.2 Codex: —
- Step 3.5 Flash: 39.6 (#132)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | — | 1421 |

## Multilingual

- GPT-5.2 Codex: —
- Step 3.5 Flash: 50.5 (#119)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | — | 1385 |
| LMArena Chinese | — | 1447 |
| LMArena French | — | 1421 |
| LMArena German | — | 1405 |
| LMArena Japanese | — | 1354 |
| LMArena Korean | — | 1352 |
| LMArena Russian | — | 1385 |
| LMArena Spanish | — | 1419 |

## Instruction Following

- GPT-5.2 Codex: —
- Step 3.5 Flash: 73.1 (#124)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1385 |

## Long Context

- GPT-5.2 Codex: —
- Step 3.5 Flash: 42.8 (#117)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | — | 1402 |

## Writing & Preference

- GPT-5.2 Codex: —
- Step 3.5 Flash: 58.8 (#113)

| Benchmark | GPT-5.2 Codex | Step 3.5 Flash |
|---|---|---|
| LMArena Text | — | 1403 |
| LMArena Creative Writing | — | 1357 |
| LMArena Multi-Turn | — | 1405 |

## FAQ

### Is GPT-5.2 Codex better than Step 3.5 Flash?

GPT-5.2 Codex and Step 3.5 Flash score almost the same on the Noometry Index (42.6 vs 42.3), so choose on price, context window or the category you care about most.

### Which is cheaper, GPT-5.2 Codex or Step 3.5 Flash?

Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; GPT-5.2 Codex lists at $1.75 and $14.

### Is GPT-5.2 Codex or Step 3.5 Flash better for coding?

GPT-5.2 Codex scores higher on coding benchmarks: 45.5 versus 42.4 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.2 Codex does, with 400K tokens against 256K.

### How many benchmarks do GPT-5.2 Codex and Step 3.5 Flash share?

0 benchmarks have published results for both models. GPT-5.2 Codex has 5 scored results on Noometry and Step 3.5 Flash has 19.