# GPT-5.3 Chat vs Step 3

> GPT-5.3 Chat is the stronger model overall, scoring 42.8 to 40.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-3-chat-vs-step-3
- Last updated: 2026-10-11
- Shared benchmarks: 15

## Summary

- They share 15 benchmarks with published results for both. GPT-5.3 Chat scores higher in 8 categories and Step 3 in 0 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where GPT-5.3 Chat leads 63.1 to 54.3.
- Step 3 has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.3 Chat | Step 3 |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 42.8 | 40.5 |
| Rank | 109 | 149 |
| Context | 128K | — |
| Input $/M | $1.75 | — |
| Output $/M | $14 | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5.3 Chat: 41.4 (#124)
- Step 3: 40.1 (#147)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Coding | 1408 | 1367 |

## Reasoning

- GPT-5.3 Chat: 28.5 (#102)
- Step 3: 28.4 (#105)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Hard Prompts | 1399 | 1355 |
| Kagi LLM Benchmark | — | 62.3% |

## Math

- GPT-5.3 Chat: 38.2 (#142)
- Step 3: 37.6 (#148)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Math | 1389 | 1366 |

## Knowledge

- GPT-5.3 Chat: 38.8 (#140)
- Step 3: 36.8 (#164)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Expert | 1397 | 1333 |

## Multimodal

- GPT-5.3 Chat: —
- Step 3: 35.5 (#86)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Vision | — | 1177 |

## Multilingual

- GPT-5.3 Chat: 50.3 (#124)
- Step 3: 46.3 (#159)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Non-English | 1382 | 1327 |
| LMArena Chinese | 1432 | 1397 |
| LMArena German | 1384 | 1371 |
| LMArena Korean | 1346 | 1269 |
| LMArena Russian | 1400 | 1331 |
| LMArena Spanish | 1371 | 1371 |
| LMArena French | 1397 | — |
| LMArena Japanese | 1352 | — |

## Instruction Following

- GPT-5.3 Chat: 72.8 (#129)
- Step 3: 70.4 (#164)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Instruction Following | 1378 | 1332 |

## Long Context

- GPT-5.3 Chat: 42.6 (#120)
- Step 3: 40.3 (#157)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Longer Query | 1396 | 1326 |

## Writing & Preference

- GPT-5.3 Chat: 63.1 (#68)
- Step 3: 54.3 (#151)

| Benchmark | GPT-5.3 Chat | Step 3 |
|---|---|---|
| LMArena Text | 1389 | 1350 |
| LMArena Creative Writing | 1355 | 1321 |
| LMArena Multi-Turn | 1412 | 1341 |
| EQ-Bench Creative Writing | 1690 | — |

## FAQ

### Is GPT-5.3 Chat better than Step 3?

GPT-5.3 Chat is the stronger model overall, scoring 42.8 to 40.5 on the Noometry Index.

### Is GPT-5.3 Chat or Step 3 better for coding?

GPT-5.3 Chat scores higher on coding benchmarks: 41.4 versus 40.1 in the Noometry coding category.

### How many benchmarks do GPT-5.3 Chat and Step 3 share?

15 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Step 3 has 17.