Model comparison
GPT-5.3 Chat vs Step 5 Preview
Step 5 Preview is the stronger model overall, scoring 47.9 to 42.8 on the Noometry Index.
Last verified . 13 shared benchmarks.
StepFunSummary
- They share 13 benchmarks with published results for both. GPT-5.3 Chat scores higher in 1 category and Step 5 Preview in 7 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 5 Preview leads 40.0 to 28.5.
- Step 5 Preview is cheaper at $1 / $2.70 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
- Step 5 Preview accepts more context: 1.02M tokens versus 128K.
Side by side
| GPT-5.3 Chat | Step 5 Preview | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 42.8 | 47.9 |
| Released | 2026-03-03 | 2026-09-16 |
| Weights | Proprietary | Proprietary |
| Context window | 128K | 1.02M |
| Max output | 16K | 66K |
| Input $ / M tokens | $1.75 | $1 |
| Output $ / M tokens | $14 | $2.70 |
| Results tracked | 18 | 18 |
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Category by category
Coding Step 5 Preview leads
GPT-5.3 Chat: 41.4 (#124), Step 5 Preview: 51.8 (#36)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Coding | 1408 | 1480 |
| LMArena WebDev | — | 1564 |
| SciCode | — | 58.9% |
Reasoning Step 5 Preview leads
GPT-5.3 Chat: 28.5 (#102), Step 5 Preview: 40.0 (#57)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Hard Prompts | 1399 | 1465 |
| CritPt | — | 20.9% |
Math Step 5 Preview leads
GPT-5.3 Chat: 38.2 (#142), Step 5 Preview: 46.1 (#72)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Math | 1389 | 1470 |
| ProofBench | — | 42% |
Knowledge Step 5 Preview leads
GPT-5.3 Chat: 38.8 (#140), Step 5 Preview: 41.2 (#112)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Expert | 1397 | 1470 |
Multimodal Not comparable
GPT-5.3 Chat: —, Step 5 Preview: 41.0 (#41)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Vision | — | 1267 |
Multilingual Step 5 Preview leads
GPT-5.3 Chat: 50.3 (#124), Step 5 Preview: 53.8 (#54)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1382 | 1432 |
| LMArena Chinese | 1432 | 1519 |
| LMArena Russian | 1400 | 1436 |
| LMArena Spanish | 1371 | 1439 |
| LMArena French | 1397 | — |
| LMArena German | 1384 | — |
| LMArena Japanese | 1352 | — |
| LMArena Korean | 1346 | — |
Instruction Following Step 5 Preview leads
GPT-5.3 Chat: 72.8 (#129), Step 5 Preview: 76.0 (#50)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1378 | 1444 |
Long Context Step 5 Preview leads
GPT-5.3 Chat: 42.6 (#120), Step 5 Preview: 44.5 (#64)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1396 | 1455 |
Writing & Preference Too close to call
GPT-5.3 Chat: 63.1 (#68), Step 5 Preview: 62.8 (#71)
| Benchmark | GPT-5.3 Chat | Step 5 Preview |
|---|---|---|
| LMArena Text | 1389 | 1442 |
| LMArena Creative Writing | 1355 | 1410 |
| LMArena Multi-Turn | 1412 | 1447 |
| EQ-Bench Creative Writing | 1690 | — |
Frequently asked questions
Is GPT-5.3 Chat better than Step 5 Preview?
Step 5 Preview is the stronger model overall, scoring 47.9 to 42.8 on the Noometry Index.
Which is cheaper, GPT-5.3 Chat or Step 5 Preview?
Step 5 Preview is cheaper. It lists at $1 per million input tokens and $2.70 per million output tokens; GPT-5.3 Chat lists at $1.75 and $14.
Is GPT-5.3 Chat or Step 5 Preview better for coding?
Step 5 Preview scores higher on coding benchmarks: 51.8 versus 41.4 in the Noometry coding category.
Which has the bigger context window?
Step 5 Preview does, with 1.02M tokens against 128K.
How many benchmarks do GPT-5.3 Chat and Step 5 Preview share?
13 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Step 5 Preview has 18.