Qwen3.5 Plus 2026-04-20 vs Step 5 Preview
Step 5 Preview leads Qwen3.5 Plus 2026-04-20 on coding, 61.1 to 39.5 on the Vibe Coding Index, and Qwen3.5 Plus 2026-04-20 costs 1.5x less per output token ($1.80 vs $2.70 per million). Updated October 22, 2026; 1 benchmarks have a result for both.
Qwen3.5 Plus 2026-04-20 or Step 5 Preview: which to pick
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 39.5 for Qwen3.5 Plus 2026-04-20.
Pick Qwen3.5 Plus 2026-04-20 for output tokens 1.5x cheaper ($1.80 vs $2.70 per million).
- Shared results
- 1
- Qwen3.5 Plus 2026-04-20 only
- 24
- Step 5 Preview only
- 60
- Like-for-like categories
- 1 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 39.5.
2 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Only Step 5 Preview has a AA Intelligence Index result, 43.7.
Directional only
Reasoning
GPQA Diamond
No call
Only Qwen3.5 Plus 2026-04-20 has a GPQA Diamond result, 87.4%.
Directional only
Math
AIME
No call
Only Qwen3.5 Plus 2026-04-20 has a AIME result, 86.0%.
Directional only
Knowledge
MMLU Pro
No call
Only Qwen3.5 Plus 2026-04-20 has a MMLU Pro result, 87.2%.
Directional only
Long documents
Listed context window
Step 5 Preview
Step 5 Preview takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Qwen3.5 Plus 2026-04-20
Qwen3.5 Plus 2026-04-20 $0.0012, Step 5 Preview $0.0024 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Qwen3.5 Plus 2026-04-20 has the number, $1.35.
Directional only
At a glance
- Coding index
- Qwen3.5 Plus 2026-04-20 39.5 from 2 benchmarks, Step 5 Preview 61.1 from 4 benchmarks.
- Widest category
- Coding, 54.7 points apart on average over 1 shared benchmark.
- Widest single gap
- Vibe Code Bench (Vals AI): Qwen3.5 Plus 2026-04-20 15.7% against Step 5 Preview 70.4%, 54.7 points apart on a 0 to 100 scale.
- Output price
- Qwen3.5 Plus 2026-04-20 $1.80 against Step 5 Preview $2.70 per million output tokens, 1.5x apart.
- Context window
- Qwen3.5 Plus 2026-04-20 takes 1M 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 | Qwen3.5 Plus 2026-04-20 | Bars | Step 5 Preview | Ties |
|---|---|---|---|---|
| Coding | 0 | 1 | ||
| All shared boards | 0 | 1 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index01
| Benchmark | Qwen3.5 Plus 2026-04-20 | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 85.6% | Only Step 5 Preview measured |
| LMArena WebDev | Not measured | 1567 | Only Step 5 Preview measured |
| LiveCodeBench (Vals AI) | 85.3% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| SWE-bench Verified (Vals AI) | 71.2% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 31.8% | Only Step 5 Preview measured |
| Vibe Code Bench (Vals AI) | 15.7% | 70.4% | Step 5 Preview |
| 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 |
| SciCode | Not measured | 58.9% | Only Step 5 Preview measured |
| ALE-Bench | 608.9 | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text: coding | Not measured | 1485 | Only Step 5 Preview measured |
| LMArena Text: software and IT | Not measured | 1473 | Only Step 5 Preview measured |
| 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 |
| Neither model has a result on the other 23 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Step 5 Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 43.7 | Only Step 5 Preview measured |
| Epoch Capabilities Index | 146.2 | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | 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 |
| Vending-Bench 2 | $1 | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Neither model has a result on the other 29 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index13 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Step 5 Preview | Leader |
|---|---|---|---|
| GPQA Diamond | 87.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LiveBench reasoning | Not measured | 83.8% | Only Step 5 Preview measured |
| MysteryMechanism (Vals AI) | Not measured | 18.5% | Only Step 5 Preview measured |
| MMMU Pro (Vals AI) | 22.8% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 46.5% | Only Step 5 Preview measured |
| GPQA Diamond (Epoch AI run) | 84.8% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Chess puzzles | 8.0% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Mystery game puzzles | 17.0% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text: hard prompts | Not measured | 1461 | Only Step 5 Preview measured |
| LMArena Text: expert | Not measured | 1485 | Only Step 5 Preview measured |
| LMArena Text: hard prompts in English | Not measured | 1454 | Only Step 5 Preview measured |
| 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 9 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Step 5 Preview | Leader |
|---|---|---|---|
| AIME | 86.0% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| OTIS Mock AIME | 86.7% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| ProofBench | Not measured | 42.0% | Only Step 5 Preview measured |
| LMArena Text: math | Not measured | 1458 | Only Step 5 Preview measured |
| LMArena Text: mathematical work | Not measured | 1460 | Only Step 5 Preview measured |
| Neither model has a result on the other 8 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index11 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | Step 5 Preview | Leader |
|---|---|---|---|
| MMLU Pro | 87.2% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LegalBench (Vals AI) | 85.1% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| CaseLaw (Vals AI) | 59.7% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| CorpFin (Vals AI) | 65.3% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| MortgageTax (Vals AI) | 60.8% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| MedQA (Vals AI) | 95.2% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| SimpleQA Verified | 25.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text: science | Not measured | 1454 | Only Step 5 Preview measured |
| LMArena Text: medicine and healthcare | Not measured | 1439 | Only Step 5 Preview measured |
| LMArena Text: legal and government | Not measured | 1437 | Only Step 5 Preview measured |
| LMArena Text: business and finance | Not measured | 1435 | Only Step 5 Preview measured |
| 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 | Qwen3.5 Plus 2026-04-20 | 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 | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index25 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | 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) | 30.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| Long context reasoning (AA-LCR) | Not measured | 88.3% | Only Step 5 Preview measured |
| DTBench | 80.5% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMCA | 36.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| CL-bench | 19.8% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| CL-bench Life | 12.4% | Not measured | Only Qwen3.5 Plus 2026-04-20 measured |
| LMArena Text | Not measured | 1440 | Only Step 5 Preview measured |
| LMArena Text: instruction following | Not measured | 1438 | Only Step 5 Preview measured |
| LMArena Text: creative writing | Not measured | 1409 | Only Step 5 Preview measured |
| LMArena Vision | Not measured | 1265 | Only Step 5 Preview measured |
| LMArena Text: English | Not measured | 1447 | Only Step 5 Preview measured |
| LMArena Text: non-English | Not measured | 1428 | Only Step 5 Preview measured |
| LMArena Text: Chinese | Not measured | 1500 | Only Step 5 Preview measured |
| LMArena Text: Japanese | Not measured | 1383 | Only Step 5 Preview measured |
| LMArena Text: French | Not measured | 1438 | Only Step 5 Preview measured |
| LMArena Text: Spanish | Not measured | 1441 | Only Step 5 Preview measured |
| LMArena Text: Russian | Not measured | 1433 | Only Step 5 Preview measured |
| LMArena Text: multi-turn | Not measured | 1437 | Only Step 5 Preview measured |
| LMArena Text: longer queries | Not measured | 1449 | Only Step 5 Preview measured |
| LMArena Text: writing and language | Not measured | 1425 | Only Step 5 Preview measured |
| LMArena Text: entertainment and media | Not measured | 1412 | Only Step 5 Preview measured |
| 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 21 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Qwen3.5 Plus 2026-04-20 | 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
Qwen3.5 Plus 2026-04-20 costs less
Repository review
50K input + 3K output tokens
Qwen3.5 Plus 2026-04-20 costs less
Agent loop
200K input + 10K output tokens
Qwen3.5 Plus 2026-04-20 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 | Qwen3.5 Plus 2026-04-20 | StepFun Step 5 Preview |
|---|---|---|
| Maker | Qwen | StepFun |
| Weights | No public weights listed | Open weights |
| Released | April 27, 2026 | October 8, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $0.30 | $1.00 |
| Output $/Mtok | $1.80 | $2.70 |
| Coding index | 39.5 | 61.1 |
| Independent measurements behind it | 2 | 4 |
| Cost per solved task | $1.35 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Qwen3.5 Plus 2026-04-20 better than Step 5 Preview for coding?
Pick Step 5 Preview for coding: it scores 61.1 on the Vibe Coding Index against 39.5 for Qwen3.5 Plus 2026-04-20. Pick Qwen3.5 Plus 2026-04-20 for output tokens 1.5x cheaper ($1.80 vs $2.70 per million).
Which is cheaper, Qwen3.5 Plus 2026-04-20 or Step 5 Preview?
Qwen3.5 Plus 2026-04-20 costs $0.30 per million input tokens and $1.80 per million output tokens; Step 5 Preview costs $1.00 and $2.70. Cost per solved task is known for Qwen3.5 Plus 2026-04-20 only.
Which has the bigger context window, Qwen3.5 Plus 2026-04-20 or Step 5 Preview?
Step 5 Preview, with 1.05M tokens against 1M.
How many benchmarks is the Qwen3.5 Plus 2026-04-20 vs Step 5 Preview comparison based on?
1 benchmarks have a result for both models as of October 22, 2026. Qwen3.5 Plus 2026-04-20's coding index rests on 2 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.