Mistral Medium 3.5 vs Step 5 Preview
Step 5 Preview leads Mistral Medium 3.5 on coding, 61.1 to 25.5 on the Vibe Coding Index, and Step 5 Preview costs 2.8x less per output token ($2.70 vs $7.50 per million). Updated October 22, 2026; 43 benchmarks have a result for both.
Mistral Medium 3.5 or Step 5 Preview: which to pick
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5.
Pick Mistral Medium 3.5 for work measured by LMArena Text: French, where it leads.
- Shared results
- 43
- Mistral Medium 3.5 only
- 38
- Step 5 Preview only
- 18
- 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 25.5.
3 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Step 5 Preview
Step 5 Preview leads, 43.7 against 14.2.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Mistral Medium 3.5 has a AA Agentic Index result, 7.0.
Directional only
Reasoning
GPQA Diamond
No call
Only Mistral Medium 3.5 has a GPQA Diamond result, 34.9%.
Directional only
Knowledge
MMLU Pro
No call
Only Mistral Medium 3.5 has a MMLU Pro result, 75.3%.
Directional only
Web design
Design Arena: websites
No call
Only Mistral Medium 3.5 has a Design Arena: websites result, 1142.
Directional only
Long documents
Listed context window
Step 5 Preview
Step 5 Preview takes 1.05M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Step 5 Preview
Mistral Medium 3.5 $0.0053, Step 5 Preview $0.0024 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Mistral Medium 3.5 has the number, $6.02.
Directional only
At a glance
- Coding index
- Mistral Medium 3.5 25.5 from 3 benchmarks, Step 5 Preview 61.1 from 4 benchmarks.
- Widest category
- Coding, 33.3 points apart on average over 8 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): Mistral Medium 3.5 2.9% against Step 5 Preview 70.4%, 67.5 points apart on a 0 to 100 scale.
- Output price
- Mistral Medium 3.5 $7.50 against Step 5 Preview $2.70 per million output tokens, 2.8x apart.
- Context window
- Mistral Medium 3.5 takes 262K 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 | Mistral Medium 3.5 | Bars | Step 5 Preview | Ties |
|---|---|---|---|---|
| Coding | 0 | 8 | ||
| Intelligence | 0 | 1 | ||
| Agentic work | 0 | 4 | ||
| Reasoning | 0 | 6 | ||
| Math | 0 | 3 | ||
| Knowledge | 0 | 4 | ||
| General | 1 | 16 | ||
| All shared boards | 1 | 42 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index08
| Benchmark | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 85.6% | Only Step 5 Preview measured |
| LMArena WebDev | 1264 | 1567 | Step 5 Preview |
| AA Coding Index | 46.9 | Not measured | Only Mistral Medium 3.5 measured |
| SWE-bench Verified (Vals AI) | 66.4% | Not measured | Only Mistral Medium 3.5 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 31.8% | Only Step 5 Preview measured |
| Vibe Code Bench (Vals AI) | 2.9% | 70.4% | Step 5 Preview |
| Code migration (Vals AI) | 5.1% | 39.0% | Step 5 Preview |
| IOI (Vals AI) | Not measured | 38.1% | Only Step 5 Preview measured |
| Terminal-Bench 2.1 (Vals AI) | 39.0% | Not measured | Only Mistral Medium 3.5 measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 40.8% | Only Step 5 Preview measured |
| SciCode | 40.2% | 58.9% | Step 5 Preview |
| Terminal-Bench Hard (Artificial Analysis run) | 33.3% | Not measured | Only Mistral Medium 3.5 measured |
| ALE-Bench | 764.0 | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Text: coding | 1460 | 1485 | Step 5 Preview |
| LMArena Text: software and IT | 1458 | 1473 | Step 5 Preview |
| LMArena WebDev: React | 1254 | 1583 | Step 5 Preview |
| LMArena WebDev: HTML | 1308 | 1556 | Step 5 Preview |
| LMArena WebDev: from an image | Not measured | 1550 | Only Step 5 Preview measured |
| Neither model has a result on the other 21 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 14.2 | 43.7 | Step 5 Preview |
| Epoch Capabilities Index | 141.4 | Not measured | Only Mistral Medium 3.5 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| AA Agentic Index | 7.0 | Not measured | Only Mistral Medium 3.5 measured |
| 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) | 32.1% | 50.7% | Step 5 Preview |
| Tax Agent Bench (Vals AI) | 4.5% | 27.3% | Step 5 Preview |
| Legal Research Bench (Vals AI) | 9.1% | 40.4% | Step 5 Preview |
| Excel Modeling Benchmark (Vals AI) | 11.2% | 57.1% | Step 5 Preview |
| 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 | 94.2% | Not measured | Only Mistral Medium 3.5 measured |
| Neither model has a result on the other 28 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| GPQA Diamond | 34.9% | Not measured | Only Mistral Medium 3.5 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) | 74.8% | Not measured | Only Mistral Medium 3.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 13.8% | 46.5% | Step 5 Preview |
| LMArena Text: hard prompts | 1436 | 1461 | Step 5 Preview |
| LMArena Text: expert | 1432 | 1485 | Step 5 Preview |
| LMArena Text: hard prompts in English | 1445 | 1454 | Step 5 Preview |
| LMArena Vision: diagrams | 1254 | 1308 | Step 5 Preview |
| LMArena Vision: homework | 1230 | 1265 | Step 5 Preview |
| Kagi LLM Benchmark | 41.4% | Not measured | Only Mistral Medium 3.5 measured |
| Neither model has a result on the other 11 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| ProofBench | 9.0% | 42.0% | Step 5 Preview |
| LMArena Text: math | 1431 | 1458 | Step 5 Preview |
| LMArena Text: mathematical work | 1440 | 1460 | 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 index04
| Benchmark | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| MMLU Pro | 75.3% | Not measured | Only Mistral Medium 3.5 measured |
| CaseLaw (Vals AI) | 44.2% | Not measured | Only Mistral Medium 3.5 measured |
| CorpFin (Vals AI) | 58.8% | Not measured | Only Mistral Medium 3.5 measured |
| TaxEval (Vals AI) | 68.0% | Not measured | Only Mistral Medium 3.5 measured |
| MortgageTax (Vals AI) | 28.9% | Not measured | Only Mistral Medium 3.5 measured |
| MedCode (Vals AI) | 33.8% | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Text: science | 1428 | 1454 | Step 5 Preview |
| LMArena Text: medicine and healthcare | 1409 | 1439 | Step 5 Preview |
| LMArena Text: legal and government | 1437 | 1437 | Step 5 Preview |
| LMArena Text: business and finance | 1426 | 1435 | 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 | Mistral Medium 3.5 | Step 5 Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1142 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: UI components | 1076 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: game dev | 1079 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: data viz | 1120 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: 3D | 1060 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: all code categories | 1121 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: SVG | 949 | Not measured | Only Mistral Medium 3.5 measured |
| Design Arena: ASCII art | 1062 | Not measured | Only Mistral Medium 3.5 measured |
| LiveBench design | Not measured | 76.9% | Only Step 5 Preview measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index116
| Benchmark | Mistral Medium 3.5 | 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 |
| SAGE (Vals AI) | 37.6% | Not measured | Only Mistral Medium 3.5 measured |
| MedScribe (Vals AI) | 67.7% | Not measured | Only Mistral Medium 3.5 measured |
| Vals Multimodal Index | 34.8% | Not measured | Only Mistral Medium 3.5 measured |
| IFBench | 68.8% | Not measured | Only Mistral Medium 3.5 measured |
| Long context reasoning (AA-LCR) | 69.3% | 88.3% | Step 5 Preview |
| DTBench | 75.5% | Not measured | Only Mistral Medium 3.5 measured |
| LMCA | 26.1% | Not measured | Only Mistral Medium 3.5 measured |
| Surface Evolver Bench | 26.9% | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Text | 1421 | 1440 | Step 5 Preview |
| LMArena Text: instruction following | 1415 | 1438 | Step 5 Preview |
| LMArena Text: creative writing | 1374 | 1409 | Step 5 Preview |
| LMArena Vision | 1222 | 1265 | Step 5 Preview |
| LMArena Text: English | 1433 | 1447 | Step 5 Preview |
| LMArena Text: non-English | 1404 | 1428 | Step 5 Preview |
| LMArena Text: Chinese | 1444 | 1500 | Step 5 Preview |
| LMArena Text: German | 1453 | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Text: Japanese | Not measured | 1383 | Only Step 5 Preview measured |
| LMArena Text: Korean | 1384 | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Text: French | 1448 | 1438 | Mistral Medium 3.5 |
| LMArena Text: Spanish | 1411 | 1441 | Step 5 Preview |
| LMArena Text: Russian | 1395 | 1433 | Step 5 Preview |
| LMArena Text: Polish | 1430 | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Text: multi-turn | 1423 | 1437 | Step 5 Preview |
| LMArena Text: longer queries | 1415 | 1449 | Step 5 Preview |
| LMArena Text: writing and language | 1384 | 1425 | Step 5 Preview |
| LMArena Text: entertainment and media | 1382 | 1412 | Step 5 Preview |
| LMArena Vision: English | 1240 | 1290 | Step 5 Preview |
| LMArena Vision: Chinese | 1244 | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Vision: reading text | 1233 | 1282 | Step 5 Preview |
| LMArena Vision: humor | 1216 | Not measured | Only Mistral Medium 3.5 measured |
| LMArena Vision: creative writing | 1198 | Not measured | Only Mistral Medium 3.5 measured |
| Neither model has a result on the other 13 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Mistral Medium 3.5 | 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 | Mistral Medium 3.5 | StepFun Step 5 Preview |
|---|---|---|
| Maker | Mistral AI | StepFun |
| Weights | No public weights listed | Open weights |
| Released | April 30, 2026 | October 8, 2026 |
| Context window | 262K | 1.05M |
| Input $/Mtok | $1.50 | $1.00 |
| Output $/Mtok | $7.50 | $2.70 |
| Coding index | 25.5 | 61.1 |
| Independent measurements behind it | 3 | 4 |
| Cost per solved task | $6.02 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Mistral Medium 3.5 better than Step 5 Preview for coding?
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5. Pick Mistral Medium 3.5 for work measured by LMArena Text: French, where it leads.
Which is cheaper, Mistral Medium 3.5 or Step 5 Preview?
Mistral Medium 3.5 costs $1.50 per million input tokens and $7.50 per million output tokens; Step 5 Preview costs $1.00 and $2.70. Cost per solved task is known for Mistral Medium 3.5 only.
Which has the bigger context window, Mistral Medium 3.5 or Step 5 Preview?
Step 5 Preview, with 1.05M tokens against 262K.
How many benchmarks is the Mistral Medium 3.5 vs Step 5 Preview comparison based on?
43 benchmarks have a result for both models as of October 22, 2026. Mistral Medium 3.5's coding index rests on 3 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.