Step 5 Preview vs MiMo-V2.5
Step 5 Preview leads MiMo-V2.5 on coding, 61.1 to 50.0 on the Vibe Coding Index, and MiMo-V2.5 costs 8.0x less per output token ($0.336 vs $2.70 per million). Updated October 22, 2026; 44 benchmarks have a result for both.
Step 5 Preview or MiMo-V2.5: which to pick
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 50.0 for MiMo-V2.5.
Pick MiMo-V2.5 for output tokens 8.0x cheaper ($0.336 vs $2.70 per million) and a larger context window (1.05M against 1.05M tokens).
- Shared results
- 44
- Step 5 Preview only
- 17
- MiMo-V2.5 only
- 36
- Like-for-like categories
- 7 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
Step 5 Preview
Step 5 Preview scores 61.1 against 50.0.
4 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Step 5 Preview
Step 5 Preview leads, 43.7 against 21.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only MiMo-V2.5 has a AA Agentic Index result, 15.8.
Directional only
Reasoning
GPQA Diamond
No call
Only MiMo-V2.5 has a GPQA Diamond result, 81.6%.
Directional only
Knowledge
MMLU Pro
No call
Only MiMo-V2.5 has a MMLU Pro result, 82.9%.
Directional only
Web design
Design Arena: websites
No call
Only MiMo-V2.5 has a Design Arena: websites result, 1265.
Directional only
Long documents
Listed context window
MiMo-V2.5
MiMo-V2.5 takes 1.05M tokens against 1.05M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
MiMo-V2.5
Step 5 Preview $0.0024, MiMo-V2.5 $0.0003 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only MiMo-V2.5 has the number, $0.01.
Directional only
At a glance
- Coding index
- Step 5 Preview 61.1 from 4 benchmarks, MiMo-V2.5 50.0 from 3 benchmarks.
- Widest category
- Intelligence, 21.9 points apart on average over 1 shared benchmark.
- Widest single gap
- Legal Research Bench (Vals AI): Step 5 Preview 40.4% against MiMo-V2.5 9.1%, 31.3 points apart on a 0 to 100 scale.
- Output price
- Step 5 Preview $2.70 against MiMo-V2.5 $0.336 per million output tokens, 8.0x apart.
- Context window
- Step 5 Preview takes 1.05M tokens, MiMo-V2.5 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 | Step 5 Preview | Bars | MiMo-V2.5 | Ties |
|---|---|---|---|---|
| Coding | 8 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 4 | 0 | ||
| Reasoning | 5 | 1 | ||
| Math | 3 | 0 | ||
| Knowledge | 4 | 0 | ||
| General | 15 | 3 | ||
| All shared boards | 40 | 4 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index80
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| LiveBench coding | 85.6% | Not measured | Only Step 5 Preview measured |
| LMArena WebDev | 1567 | 1438 | Step 5 Preview |
| AA Coding Index | Not measured | 56.8 | Only MiMo-V2.5 measured |
| LiveCodeBench (Vals AI) | Not measured | 81.5% | Only MiMo-V2.5 measured |
| SWE-bench Verified (Vals AI) | Not measured | 71.0% | Only MiMo-V2.5 measured |
| Terminal-Bench 4 (Vals AI) | 31.8% | Not measured | Only Step 5 Preview measured |
| Vibe Code Bench (Vals AI) | 70.4% | 42.2% | Step 5 Preview |
| Code migration (Vals AI) | 39.0% | 14.2% | Step 5 Preview |
| IOI (Vals AI) | 38.1% | Not measured | Only Step 5 Preview measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 60.7% | Only MiMo-V2.5 measured |
| SWE-bench Multimodal (Vals AI) | 40.8% | Not measured | Only Step 5 Preview measured |
| SciCode | 58.9% | 43.9% | Step 5 Preview |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 41.7% | Only MiMo-V2.5 measured |
| ALE-Bench | Not measured | 514.0 | Only MiMo-V2.5 measured |
| LMArena Text: coding | 1485 | 1469 | Step 5 Preview |
| LMArena Text: software and IT | 1473 | 1463 | Step 5 Preview |
| LMArena WebDev: React | 1583 | 1425 | Step 5 Preview |
| LMArena WebDev: HTML | 1556 | 1429 | Step 5 Preview |
| LMArena WebDev: from an image | 1550 | Not measured | Only Step 5 Preview measured |
| Neither model has a result on the other 20 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 43.7 | 21.8 | Step 5 Preview |
| Neither model has a result on the other 1 board here | |||
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 15.8 | Only MiMo-V2.5 measured |
| LiveBench research | 72.8% | Not measured | Only Step 5 Preview measured |
| LiveBench browser | 24.0% | Not measured | Only Step 5 Preview measured |
| LiveBench long agentic | 27.5% | Not measured | Only Step 5 Preview measured |
| SREBench (Vals AI) | 0.4% | Not measured | Only Step 5 Preview measured |
| Finance Agent (Vals AI) | 50.7% | 36.7% | Step 5 Preview |
| Tax Agent Bench (Vals AI) | 27.3% | 7.8% | Step 5 Preview |
| Legal Research Bench (Vals AI) | 40.4% | 9.1% | Step 5 Preview |
| Excel Modeling Benchmark (Vals AI) | 57.1% | 55.1% | Step 5 Preview |
| BioMysteryBench (Vals AI) | 67.4% | Not measured | Only Step 5 Preview measured |
| Terminal-Bench-Science (Vals AI) | 2.9% | Not measured | Only Step 5 Preview measured |
| Vals Science Index | 29.6% | Not measured | Only Step 5 Preview measured |
| τ²-Bench Telecom | Not measured | 90.6% | Only MiMo-V2.5 measured |
| Neither model has a result on the other 28 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index51
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 81.6% | Only MiMo-V2.5 measured |
| LiveBench reasoning | 83.8% | Not measured | Only Step 5 Preview measured |
| MysteryMechanism (Vals AI) | 18.5% | Not measured | Only Step 5 Preview measured |
| MMMU Pro (Vals AI) | Not measured | 80.0% | Only MiMo-V2.5 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 84.9% | Only MiMo-V2.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 46.5% | 27.2% | Step 5 Preview |
| LMArena Text: hard prompts | 1461 | 1450 | Step 5 Preview |
| LMArena Text: expert | 1485 | 1459 | Step 5 Preview |
| LMArena Text: hard prompts in English | 1454 | 1461 | MiMo-V2.5 |
| LMArena Vision: diagrams | 1308 | 1269 | Step 5 Preview |
| LMArena Vision: homework | 1265 | 1262 | Step 5 Preview |
| Neither model has a result on the other 11 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| ProofBench | 42.0% | 16.0% | Step 5 Preview |
| LMArena Text: math | 1458 | 1436 | Step 5 Preview |
| LMArena Text: mathematical work | 1460 | 1451 | Step 5 Preview |
| Neither model has a result on the other 10 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 82.9% | Only MiMo-V2.5 measured |
| LegalBench (Vals AI) | Not measured | 78.9% | Only MiMo-V2.5 measured |
| CorpFin (Vals AI) | Not measured | 59.9% | Only MiMo-V2.5 measured |
| TaxEval (Vals AI) | Not measured | 71.8% | Only MiMo-V2.5 measured |
| MortgageTax (Vals AI) | Not measured | 59.3% | Only MiMo-V2.5 measured |
| MedCode (Vals AI) | Not measured | 31.9% | Only MiMo-V2.5 measured |
| LMArena Text: science | 1454 | 1440 | Step 5 Preview |
| LMArena Text: medicine and healthcare | 1439 | 1432 | Step 5 Preview |
| LMArena Text: legal and government | 1437 | 1425 | Step 5 Preview |
| LMArena Text: business and finance | 1435 | 1432 | Step 5 Preview |
| Neither model has a result on the other 8 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1265 | Only MiMo-V2.5 measured |
| Design Arena: UI components | Not measured | 1255 | Only MiMo-V2.5 measured |
| Design Arena: game dev | Not measured | 1249 | Only MiMo-V2.5 measured |
| Design Arena: data viz | Not measured | 1250 | Only MiMo-V2.5 measured |
| Design Arena: 3D | Not measured | 1215 | Only MiMo-V2.5 measured |
| Design Arena: all code categories | Not measured | 1260 | Only MiMo-V2.5 measured |
| Design Arena: SVG | Not measured | 1179 | Only MiMo-V2.5 measured |
| Design Arena: ASCII art | Not measured | 1140 | Only MiMo-V2.5 measured |
| LiveBench design | 76.9% | Not measured | Only Step 5 Preview measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index153
| Benchmark | Step 5 Preview | MiMo-V2.5 | Leader |
|---|---|---|---|
| LiveBench data analysis | 63.5% | Not measured | Only Step 5 Preview measured |
| Public Benefits Bench (Vals AI) | 58.1% | Not measured | Only Step 5 Preview measured |
| SAGE (Vals AI) | Not measured | 43.3% | Only MiMo-V2.5 measured |
| MedScribe (Vals AI) | Not measured | 72.2% | Only MiMo-V2.5 measured |
| Vals Multimodal Index | Not measured | 52.8% | Only MiMo-V2.5 measured |
| IFBench | Not measured | 67.1% | Only MiMo-V2.5 measured |
| Long context reasoning (AA-LCR) | 88.3% | 73.0% | Step 5 Preview |
| LMArena Text | 1440 | 1428 | Step 5 Preview |
| LMArena Text: instruction following | 1438 | 1435 | Step 5 Preview |
| LMArena Text: creative writing | 1409 | 1393 | Step 5 Preview |
| LMArena Vision | 1265 | 1247 | Step 5 Preview |
| LMArena Text: English | 1447 | 1447 | MiMo-V2.5 |
| LMArena Text: non-English | 1428 | 1405 | Step 5 Preview |
| LMArena Text: Chinese | 1500 | 1469 | Step 5 Preview |
| LMArena Text: German | Not measured | 1421 | Only MiMo-V2.5 measured |
| LMArena Text: Japanese | 1383 | 1306 | Step 5 Preview |
| LMArena Text: Korean | Not measured | 1361 | Only MiMo-V2.5 measured |
| LMArena Text: French | 1438 | 1448 | MiMo-V2.5 |
| LMArena Text: Spanish | 1441 | 1414 | Step 5 Preview |
| LMArena Text: Russian | 1433 | 1396 | Step 5 Preview |
| LMArena Text: Polish | Not measured | 1413 | Only MiMo-V2.5 measured |
| LMArena Text: multi-turn | 1437 | 1445 | MiMo-V2.5 |
| LMArena Text: longer queries | 1449 | 1445 | Step 5 Preview |
| LMArena Text: writing and language | 1425 | 1409 | Step 5 Preview |
| LMArena Text: entertainment and media | 1412 | 1399 | Step 5 Preview |
| LMArena Vision: English | 1290 | 1259 | Step 5 Preview |
| LMArena Vision: Chinese | Not measured | 1326 | Only MiMo-V2.5 measured |
| LMArena Vision: reading text | 1282 | 1256 | Step 5 Preview |
| LMArena Vision: humor | Not measured | 1226 | Only MiMo-V2.5 measured |
| LMArena Vision: recognizing things | Not measured | 1189 | Only MiMo-V2.5 measured |
| LMArena Vision: creative writing | Not measured | 1230 | Only MiMo-V2.5 measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Step 5 Preview | MiMo-V2.5 | 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
MiMo-V2.5 costs less
Repository review
50K input + 3K output tokens
MiMo-V2.5 costs less
Agent loop
200K input + 10K output tokens
MiMo-V2.5 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 | StepFun Step 5 Preview | Xiaomi MiMo-V2.5 |
|---|---|---|
| Maker | StepFun | Xiaomi |
| Weights | Open weights | Open weights |
| Released | October 8, 2026 | April 22, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $1.00 | $0.168 |
| Output $/Mtok | $2.70 | $0.336 |
| Coding index | 61.1 | 50.0 |
| Independent measurements behind it | 4 | 3 |
| Cost per solved task | Not computable | $0.01 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Step 5 Preview better than MiMo-V2.5 for coding?
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 50.0 for MiMo-V2.5. Pick MiMo-V2.5 for output tokens 8.0x cheaper ($0.336 vs $2.70 per million) and a larger context window (1.05M against 1.05M tokens).
Which is cheaper, Step 5 Preview or MiMo-V2.5?
Step 5 Preview costs $1.00 per million input tokens and $2.70 per million output tokens; MiMo-V2.5 costs $0.168 and $0.336. Cost per solved task is known for MiMo-V2.5 only.
Which has the bigger context window, Step 5 Preview or MiMo-V2.5?
MiMo-V2.5, with 1.05M tokens against 1.05M.
How many benchmarks is the Step 5 Preview vs MiMo-V2.5 comparison based on?
44 benchmarks have a result for both models as of October 22, 2026. Step 5 Preview's coding index rests on 4 independent benchmarks and MiMo-V2.5's on 3. Where only one model has a result, the page says so instead of naming a winner.