Model comparison
GPT-4o mini vs Step 3.5 Flash
Step 3.5 Flash is the stronger model overall, scoring 41.7 to 25.4 on the Noometry Index.
Last verified . 17 shared benchmarks.
StepFunSummary
- They share 17 benchmarks with published results for both. GPT-4o mini scores higher in 0 categories and Step 3.5 Flash in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Step 3.5 Flash leads 40.6 to 9.9.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.15 / $0.60 for GPT-4o mini.
- Step 3.5 Flash accepts more context: 256K tokens versus 128K.
- Step 3.5 Flash has downloadable open weights; the other is API-only.
Side by side
| GPT-4o mini | Step 3.5 Flash | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 25.4 | 41.7 |
| Released | 2024-07-18 | 2026-01-29 |
| Weights | Proprietary | Open |
| Context window | 128K | 256K |
| Max output | 16K | 256K |
| Input $ / M tokens | $0.15 | $0.10 |
| Output $ / M tokens | $0.60 | $0.30 |
| Results tracked | 60 | 19 |
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Category by category
Coding Step 3.5 Flash leads
GPT-4o mini: 21.6 (#330), Step 3.5 Flash: 41.7 (#106)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1290 | 1436 |
| Aider Polyglot | 3.6% | — |
| WeirdML | 11.8% | — |
| BigCodeBench Instruct | 46.1% | — |
| LiveBench Coding | 43.1% | — |
| BigCodeBench Complete | 57.4% | — |
| HumanEval+ | 83.5% | — |
| MBPP+ | 72.2% | — |
Agentic & Tool Use Not comparable
GPT-4o mini: 27.2 (#95), Step 3.5 Flash: —
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| BALROG | 17.4% | — |
Reasoning Step 3.5 Flash leads
GPT-4o mini: 8.7 (#343), Step 3.5 Flash: 21.2 (#202)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1267 | 1411 |
| ARC-AGI-2 | 0% | — |
| SimpleBench | 10.7% | — |
| Kagi LLM Benchmark | 28.8% | — |
| NYT Connections (extended) | — | 28.4% |
| Chess Puzzles | 0% | — |
| LiveBench Reasoning | 32.8% | — |
| Mystery Game Puzzles | 12% | — |
| DTBench | 54.4% | — |
| LiveBench Data Analysis | 50% | — |
| LMCA | 10.4% | — |
| Epoch Capabilities Index | 126.56 | — |
| LiveBench | 41.3% | — |
| PIQA | 88.7% | — |
Math Step 3.5 Flash leads
GPT-4o mini: 9.9 (#307), Step 3.5 Flash: 40.6 (#77)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1267 | 1408 |
| FrontierMath (Tiers 1-3) | 0.7% | — |
| MathArena Final-Answer Competitions | — | 66.8% |
| OTIS Mock AIME 2024-2025 | 6.9% | — |
| Omni-MATH | 28% | — |
| LiveBench Math | 36.3% | — |
| MATH Level 5 | 52.6% | — |
| GSM8K | 91.3% | — |
Knowledge Step 3.5 Flash leads
GPT-4o mini: 17.7 (#279), Step 3.5 Flash: 39.0 (#127)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1235 | 1422 |
| GPQA Diamond | 37.7% | — |
| SimpleQA Verified | 8.3% | — |
| MMLU-Pro | 60.3% | — |
| Confabulations | 37.2% | — |
| GPQA (HELM) | 36.8% | — |
| BoolQ | 88.7% | — |
| MMLU | 81.8% | — |
Multimodal Not comparable
GPT-4o mini: 25.3 (#117), Step 3.5 Flash: —
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Vision | 1066 | — |
| Video-MME | 64.8% | — |
| GeoBench | 64% | — |
| VPCT | 34% | — |
Multilingual Step 3.5 Flash leads
GPT-4o mini: 42.2 (#194), Step 3.5 Flash: 50.7 (#115)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1266 | 1386 |
| LMArena Chinese | 1264 | 1448 |
| LMArena French | 1296 | 1421 |
| LMArena German | 1272 | 1404 |
| LMArena Japanese | 1216 | 1353 |
| LMArena Korean | 1195 | 1350 |
| LMArena Russian | 1275 | 1385 |
| LMArena Spanish | 1276 | 1419 |
Instruction Following Step 3.5 Flash leads
GPT-4o mini: 62.1 (#234), Step 3.5 Flash: 73.3 (#119)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1259 | 1385 |
| LiveBench Instruction Following | 56.8% | — |
| IFEval | 78.2% | — |
Long Context Step 3.5 Flash leads
GPT-4o mini: 39.1 (#181), Step 3.5 Flash: 42.8 (#112)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1289 | 1402 |
Writing & Preference Step 3.5 Flash leads
GPT-4o mini: 39.7 (#243), Step 3.5 Flash: 59.0 (#108)
| Benchmark | GPT-4o mini | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1286 | 1403 |
| LMArena Creative Writing | 1268 | 1357 |
| LMArena Multi-Turn | 1285 | 1405 |
| Short-Story Creative Writing | 67.2% | — |
| EQ-Bench Creative Writing | 873 | — |
| WildBench | 79.1% | — |
| LiveBench Language | 28.6% | — |
Frequently asked questions
Is GPT-4o mini better than Step 3.5 Flash?
Step 3.5 Flash is the stronger model overall, scoring 41.7 to 25.4 on the Noometry Index.
Which is cheaper, GPT-4o mini 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-4o mini lists at $0.15 and $0.60.
Is GPT-4o mini or Step 3.5 Flash better for coding?
Step 3.5 Flash scores higher on coding benchmarks: 41.7 versus 21.6 in the Noometry coding category.
Which has the bigger context window?
Step 3.5 Flash does, with 256K tokens against 128K.
How many benchmarks do GPT-4o mini and Step 3.5 Flash share?
17 benchmarks have published results for both models. GPT-4o mini has 60 scored results on Noometry and Step 3.5 Flash has 19.