Model comparison
GPT-5.4 nano vs Step 3.5 Flash
GPT-5.4 nano and Step 3.5 Flash score almost the same on the Noometry Index (41.9 vs 42.3), so choose on price, context window or the category you care about most.
Last verified . 17 shared benchmarks.
StepFunSummary
- They share 17 benchmarks with published results for both. GPT-5.4 nano scores higher in 3 categories and Step 3.5 Flash in 5 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Step 3.5 Flash leads 58.8 to 55.7.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.20 / $1.25 for GPT-5.4 nano.
- GPT-5.4 nano accepts more context: 400K tokens versus 256K.
- Step 3.5 Flash has downloadable open weights; the other is API-only.
Side by side
| GPT-5.4 nano | Step 3.5 Flash | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 41.9 | 42.3 |
| Released | 2026-03-17 | 2026-01-29 |
| Weights | Proprietary | Open |
| Context window | 400K | 256K |
| Max output | 128K | 256K |
| Input $ / M tokens | $0.20 | $0.10 |
| Output $ / M tokens | $1.25 | $0.30 |
| Results tracked | 40 | 19 |
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Category by category
Coding GPT-5.4 nano leads
GPT-5.4 nano: 43.6 (#84), Step 3.5 Flash: 42.4 (#105)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1405 | 1436 |
| SciCode | 46.9% | — |
| WeirdML | 49.2% | — |
| ALE-Bench | 1,005 | — |
Reasoning GPT-5.4 nano leads
GPT-5.4 nano: 23.7 (#173), Step 3.5 Flash: 22.2 (#202)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1381 | 1411 |
| ARC-AGI-2 | 5.7% | — |
| Kagi LLM Benchmark | 39.7% | — |
| NYT Connections (extended) | — | 28.4% |
| ARC-AGI-1 | 51.5% | — |
| CritPt | 9.3% | — |
| Chess Puzzles | 30% | — |
| Mystery Game Puzzles | 9% | — |
| DTBench | 80.3% | — |
| LMCA | 36.9% | — |
| Epoch Capabilities Index | 145.81 | — |
| ForecastBench | 57.3 | — |
Math Step 3.5 Flash leads
GPT-5.4 nano: 40.9 (#88), Step 3.5 Flash: 42.6 (#84)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1406 | 1408 |
| FrontierMath (Tiers 1-3) | 44.9% | — |
| FrontierMath Tier 4 | 12.2% | — |
| MathArena Final-Answer Competitions | — | 66.8% |
| OTIS Mock AIME 2024-2025 | 87.8% | — |
| ProofBench | 5% | — |
| FrontierMath (Feb 2025 set) | 25.9% | — |
| FrontierMath Tier 4 (v1) | 6.3% | — |
Knowledge GPT-5.4 nano leads
GPT-5.4 nano: 41.9 (#103), Step 3.5 Flash: 39.6 (#132)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1396 | 1421 |
| GPQA Diamond | 78.5% | — |
| SimpleQA Verified | 11.7% | — |
| Vectara Hallucination Rate | 3.1% | — |
Multimodal Not comparable
GPT-5.4 nano: 36.7 (#78), Step 3.5 Flash: —
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Vision | 1196 | — |
Multilingual Step 3.5 Flash leads
GPT-5.4 nano: 48.6 (#140), Step 3.5 Flash: 50.5 (#119)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1359 | 1385 |
| LMArena Chinese | 1392 | 1447 |
| LMArena French | 1396 | 1421 |
| LMArena German | 1367 | 1405 |
| LMArena Japanese | 1343 | 1354 |
| LMArena Korean | 1320 | 1352 |
| LMArena Russian | 1363 | 1385 |
| LMArena Spanish | 1371 | 1419 |
Instruction Following Step 3.5 Flash leads
GPT-5.4 nano: 71.9 (#144), Step 3.5 Flash: 73.1 (#124)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1362 | 1385 |
Long Context Step 3.5 Flash leads
GPT-5.4 nano: 41.6 (#137), Step 3.5 Flash: 42.8 (#117)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1366 | 1402 |
Writing & Preference Step 3.5 Flash leads
GPT-5.4 nano: 55.7 (#142), Step 3.5 Flash: 58.8 (#113)
| Benchmark | GPT-5.4 nano | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1372 | 1403 |
| LMArena Creative Writing | 1314 | 1357 |
| LMArena Multi-Turn | 1382 | 1405 |
Frequently asked questions
Is GPT-5.4 nano better than Step 3.5 Flash?
GPT-5.4 nano and Step 3.5 Flash score almost the same on the Noometry Index (41.9 vs 42.3), so choose on price, context window or the category you care about most.
Which is cheaper, GPT-5.4 nano 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-5.4 nano lists at $0.20 and $1.25.
Is GPT-5.4 nano or Step 3.5 Flash better for coding?
GPT-5.4 nano scores higher on coding benchmarks: 43.6 versus 42.4 in the Noometry coding category.
Which has the bigger context window?
GPT-5.4 nano does, with 400K tokens against 256K.
How many benchmarks do GPT-5.4 nano and Step 3.5 Flash share?
17 benchmarks have published results for both models. GPT-5.4 nano has 40 scored results on Noometry and Step 3.5 Flash has 19.