o3 Mini vs Step 5 Preview
Step 5 Preview leads o3 Mini on the Artificial Analysis Intelligence Index, 43.7 to 12.5, and Step 5 Preview costs 1.6x less per output token ($2.70 vs $4.40 per million). Updated October 22, 2026; 29 benchmarks have a result for both.
o3 Mini or Step 5 Preview: which to pick
Only Step 5 Preview has a coding score, 61.1 on the Vibe Coding Index; o3 Mini has none, so the two cannot be ranked on coding.
Compare them on price, context and the boards below.
- Shared results
- 29
- o3 Mini only
- 42
- Step 5 Preview only
- 32
- Like-for-like categories
- 6 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Only Step 5 Preview has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Step 5 Preview
Step 5 Preview leads, 43.7 against 12.5.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only o3 Mini has a GPQA Diamond result, 75.5%.
Directional only
Math
AIME
No call
Only o3 Mini has a AIME result, 86.5%.
Directional only
Knowledge
MMLU Pro
No call
Only o3 Mini has a MMLU Pro result, 78.7%.
Directional only
Long documents
Listed context window
Step 5 Preview
Step 5 Preview takes 1.05M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Step 5 Preview
o3 Mini $0.0033, Step 5 Preview $0.0024 per turn.
List prices
At a glance
- Coding index
- o3 Mini not benchmarked, Step 5 Preview 61.1 from 4 benchmarks.
- Widest category
- Intelligence, 31.2 points apart on average over 1 shared benchmark.
- Widest single gap
- Long context reasoning (AA-LCR): o3 Mini 43.0% against Step 5 Preview 88.3%, 45.3 points apart on a 0 to 100 scale.
- Output price
- o3 Mini $4.40 against Step 5 Preview $2.70 per million output tokens, 1.6x apart.
- Context window
- o3 Mini takes 200K tokens, Step 5 Preview 1.05M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | o3 Mini | Bars | Step 5 Preview | Ties |
|---|---|---|---|---|
| Coding | 0 | 3 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 0 | 4 | ||
| Math | 0 | 2 | ||
| Knowledge | 0 | 4 | ||
| General | 0 | 15 | ||
| All shared boards | 0 | 29 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index03
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| Aider polyglot | 60.4% | Not measured | Only o3 Mini measured |
| SWE-bench Verified | 42.4% | Not measured | Only o3 Mini measured |
| SWE-bench Lite | 32.3% | Not measured | Only o3 Mini measured |
| LiveBench coding | Not measured | 85.6% | Only Step 5 Preview measured |
| LMArena WebDev | Not measured | 1567 | Only Step 5 Preview measured |
| LiveCodeBench (Vals AI) | 71.5% | Not measured | Only o3 Mini measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 31.8% | Only Step 5 Preview measured |
| Vibe Code Bench (Vals AI) | Not measured | 70.4% | Only Step 5 Preview measured |
| Code migration (Vals AI) | Not measured | 39.0% | Only Step 5 Preview measured |
| IOI (Vals AI) | Not measured | 38.1% | Only Step 5 Preview measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 40.8% | Only Step 5 Preview measured |
| LiveCodeBench (Artificial Analysis run) | 73.4% | Not measured | Only o3 Mini measured |
| SciCode | 42.8% | 58.9% | Step 5 Preview |
| Terminal-Bench Hard (Artificial Analysis run) | 6.8% | Not measured | Only o3 Mini measured |
| GSO-Bench | 1.3% | Not measured | Only o3 Mini measured |
| WeirdML | 43.7% | Not measured | Only o3 Mini measured |
| Cybench | 22.5% | Not measured | Only o3 Mini measured |
| LMArena Text: coding | 1378 | 1485 | Step 5 Preview |
| LMArena Text: software and IT | 1364 | 1473 | Step 5 Preview |
| LMArena WebDev: React | Not measured | 1583 | Only Step 5 Preview measured |
| LMArena WebDev: HTML | Not measured | 1556 | Only Step 5 Preview measured |
| LMArena WebDev: from an image | Not measured | 1550 | Only Step 5 Preview measured |
| SciCode | 7.7% | Not measured | Only o3 Mini measured |
| Neither model has a result on the other 16 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 12.5 | 43.7 | Step 5 Preview |
| Epoch Capabilities Index | 140.2 | Not measured | Only o3 Mini measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench research | Not measured | 72.8% | Only Step 5 Preview measured |
| LiveBench browser | Not measured | 24.0% | Only Step 5 Preview measured |
| LiveBench long agentic | Not measured | 27.5% | Only Step 5 Preview measured |
| SREBench (Vals AI) | Not measured | 0.4% | Only Step 5 Preview measured |
| Finance Agent (Vals AI) | Not measured | 50.7% | Only Step 5 Preview measured |
| Tax Agent Bench (Vals AI) | Not measured | 27.3% | Only Step 5 Preview measured |
| Legal Research Bench (Vals AI) | Not measured | 40.4% | Only Step 5 Preview measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 57.1% | Only Step 5 Preview measured |
| BioMysteryBench (Vals AI) | Not measured | 67.4% | Only Step 5 Preview measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 2.9% | Only Step 5 Preview measured |
| Vals Science Index | Not measured | 29.6% | Only Step 5 Preview measured |
| τ²-Bench Telecom | 31.3% | Not measured | Only o3 Mini measured |
| Neither model has a result on the other 29 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| GPQA Diamond | 75.5% | Not measured | Only o3 Mini measured |
| LiveBench reasoning | Not measured | 83.8% | Only Step 5 Preview measured |
| MysteryMechanism (Vals AI) | Not measured | 18.5% | Only Step 5 Preview measured |
| GPQA Diamond (Artificial Analysis run) | 77.3% | Not measured | Only o3 Mini measured |
| Humanity's Last Exam (Artificial Analysis run) | 12.0% | 46.5% | Step 5 Preview |
| GPQA Diamond (Epoch AI run) | 77.0% | Not measured | Only o3 Mini measured |
| ARC-AGI | 34.5% | Not measured | Only o3 Mini measured |
| ARC-AGI-2 | 3.0% | Not measured | Only o3 Mini measured |
| SimpleBench | 22.8% | Not measured | Only o3 Mini measured |
| Chess puzzles | 15.0% | Not measured | Only o3 Mini measured |
| Mystery game puzzles | 7.0% | Not measured | Only o3 Mini measured |
| LMArena Text: hard prompts | 1365 | 1461 | Step 5 Preview |
| LMArena Text: expert | 1364 | 1485 | Step 5 Preview |
| LMArena Text: hard prompts in English | 1375 | 1454 | Step 5 Preview |
| LMArena Vision: diagrams | Not measured | 1308 | Only Step 5 Preview measured |
| LMArena Vision: homework | Not measured | 1265 | Only Step 5 Preview measured |
| Neither model has a result on the other 6 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| AIME | 86.5% | Not measured | Only o3 Mini measured |
| MATH 500 (Vals AI) | 91.8% | Not measured | Only o3 Mini measured |
| MGSM (Vals AI) | 91.3% | Not measured | Only o3 Mini measured |
| OTIS Mock AIME | 76.9% | Not measured | Only o3 Mini measured |
| FrontierMath, tiers 1 to 3 | 18.6% | Not measured | Only o3 Mini measured |
| FrontierMath, tier 4 | 0.0% | Not measured | Only o3 Mini measured |
| ProofBench | Not measured | 42.0% | Only Step 5 Preview measured |
| MATH level 5 | 96.5% | Not measured | Only o3 Mini measured |
| LMArena Text: math | 1396 | 1458 | Step 5 Preview |
| LMArena Text: mathematical work | 1399 | 1460 | Step 5 Preview |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| MMLU Pro | 78.7% | Not measured | Only o3 Mini measured |
| LegalBench (Vals AI) | 71.5% | Not measured | Only o3 Mini measured |
| CorpFin (Vals AI) | 45.3% | Not measured | Only o3 Mini measured |
| TaxEval (Vals AI) | 69.4% | Not measured | Only o3 Mini measured |
| MedQA (Vals AI) | 94.8% | Not measured | Only o3 Mini measured |
| MMLU Pro (Artificial Analysis run) | 80.2% | Not measured | Only o3 Mini measured |
| SimpleQA Verified | 15.3% | Not measured | Only o3 Mini measured |
| LMArena Text: science | 1339 | 1454 | Step 5 Preview |
| LMArena Text: medicine and healthcare | 1330 | 1439 | Step 5 Preview |
| LMArena Text: legal and government | 1328 | 1437 | Step 5 Preview |
| LMArena Text: business and finance | 1313 | 1435 | Step 5 Preview |
| Neither model has a result on the other 7 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench design | Not measured | 76.9% | Only Step 5 Preview measured |
| Neither model has a result on the other 8 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index015
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench data analysis | Not measured | 63.5% | Only Step 5 Preview measured |
| Public Benefits Bench (Vals AI) | Not measured | 58.1% | Only Step 5 Preview measured |
| IFBench | 67.1% | Not measured | Only o3 Mini measured |
| Long context reasoning (AA-LCR) | 43.0% | 88.3% | Step 5 Preview |
| DTBench | 68.8% | Not measured | Only o3 Mini measured |
| LMCA | 19.0% | Not measured | Only o3 Mini measured |
| Fiction.LiveBench | 50.0% | Not measured | Only o3 Mini measured |
| Creative writing (Lech Mazur) | 61.7% | Not measured | Only o3 Mini measured |
| LMArena Text | 1337 | 1440 | Step 5 Preview |
| LMArena Text: instruction following | 1337 | 1438 | Step 5 Preview |
| LMArena Text: creative writing | 1286 | 1409 | Step 5 Preview |
| LMArena Vision | Not measured | 1265 | Only Step 5 Preview measured |
| LMArena Text: English | 1351 | 1447 | Step 5 Preview |
| LMArena Text: non-English | 1319 | 1428 | Step 5 Preview |
| LMArena Text: Chinese | 1379 | 1500 | Step 5 Preview |
| LMArena Text: German | 1303 | Not measured | Only o3 Mini measured |
| LMArena Text: Japanese | 1286 | 1383 | Step 5 Preview |
| LMArena Text: Korean | 1313 | Not measured | Only o3 Mini measured |
| LMArena Text: French | 1334 | 1438 | Step 5 Preview |
| LMArena Text: Spanish | 1321 | 1441 | Step 5 Preview |
| LMArena Text: Russian | 1304 | 1433 | Step 5 Preview |
| LMArena Text: Polish | 1294 | Not measured | Only o3 Mini measured |
| LMArena Text: multi-turn | 1320 | 1437 | Step 5 Preview |
| LMArena Text: longer queries | 1343 | 1449 | Step 5 Preview |
| LMArena Text: writing and language | 1313 | 1425 | Step 5 Preview |
| LMArena Text: entertainment and media | 1283 | 1412 | Step 5 Preview |
| LMArena Vision: English | Not measured | 1290 | Only Step 5 Preview measured |
| LMArena Vision: reading text | Not measured | 1282 | Only Step 5 Preview measured |
| Neither model has a result on the other 18 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | o3 Mini | Step 5 Preview | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Step 5 Preview costs less
Repository review
50K input + 3K output tokens
Step 5 Preview costs less
Agent loop
200K input + 10K output tokens
Step 5 Preview costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | OpenAI o3 Mini | StepFun Step 5 Preview |
|---|---|---|
| Maker | OpenAI | StepFun |
| Weights | No public weights listed | Open weights |
| Released | January 31, 2025 | October 8, 2026 |
| Context window | 200K | 1.05M |
| Input $/Mtok | $1.10 | $1.00 |
| Output $/Mtok | $4.40 | $2.70 |
| Coding index | Not benchmarked | 61.1 |
| Independent measurements behind it | 0 | 4 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is o3 Mini better than Step 5 Preview for coding?
Only Step 5 Preview has a coding score, 61.1 on the Vibe Coding Index; o3 Mini has none, so the two cannot be ranked on coding. Compare them on price, context and the boards below.
Which is cheaper, o3 Mini or Step 5 Preview?
o3 Mini costs $1.10 per million input tokens and $4.40 per million output tokens; Step 5 Preview costs $1.00 and $2.70. Cost per solved task is known for neither of them.
Which has the bigger context window, o3 Mini or Step 5 Preview?
Step 5 Preview, with 1.05M tokens against 200K.
How many benchmarks is the o3 Mini vs Step 5 Preview comparison based on?
29 benchmarks have a result for both models as of October 22, 2026. o3 Mini's coding index rests on 0 independent benchmarks and Step 5 Preview's on 4. Where only one model has a result, the page says so instead of naming a winner.