Grok 4.3 vs Step 5 Preview
Updated October 21, 2026. 46 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Step 5 Preview for coding: it scores 71.4 on the Vibe Coding Index against 22.5 for Grok 4.3.
Pick Grok 4.3 when output tokens cost 1.1x less.
- Shared results
- 46
- Grok 4.3 only
- 58
- Step 5 Preview only
- 15
- Like-for-like categories
- 7 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
Step 5 Preview
Step 5 Preview scores 71.4 against 22.5.
1 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
Step 5 Preview
Step 5 Preview leads, 43.7 against 24.9.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Grok 4.3 has a AA Agentic Index result, 15.5.
Directional only
Reasoning
GPQA Diamond
No call
Only Grok 4.3 has a GPQA Diamond result, 91.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Grok 4.3 has a MMLU Pro result, 85.8%.
Directional only
Web design
Design Arena: websites
No call
Only Grok 4.3 has a Design Arena: websites result, 1196.
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
Step 5 Preview
Grok 4.3 $0.0025, Step 5 Preview $0.0024 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Grok 4.3 has the number, $0.31.
Directional only
At a glance
- Coding index
- Grok 4.3 22.5 from 1 benchmark, Step 5 Preview 71.4 from 2 benchmarks.
- Widest category
- Coding, 27.1 points apart on average over 9 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): Grok 4.3 19.4% against Step 5 Preview 70.4%, 51.0 points apart on a 0 to 100 scale.
- Output price
- Grok 4.3 $2.50 against Step 5 Preview $2.70 per million output tokens, 1.1x apart.
- Context window
- Grok 4.3 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 | Grok 4.3 | Bars | Step 5 Preview | Ties |
|---|---|---|---|---|
| Coding | 0 | 9 | ||
| Intelligence | 0 | 1 | ||
| Agentic work | 0 | 4 | ||
| Reasoning | 0 | 6 | ||
| Math | 0 | 3 | ||
| Knowledge | 0 | 4 | ||
| General | 0 | 19 | ||
| All shared boards | 0 | 46 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index09
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 85.6% | Only Step 5 Preview measured |
| LMArena WebDev | 1358 | 1567 | Step 5 Preview |
| AA Coding Index | 42.2 | Not measured | Only Grok 4.3 measured |
| LiveCodeBench (Vals AI) | 84.5% | Not measured | Only Grok 4.3 measured |
| SWE-bench Verified (Vals AI) | 71.4% | Not measured | Only Grok 4.3 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 31.8% | Only Step 5 Preview measured |
| Vibe Code Bench (Vals AI) | 19.4% | 70.4% | Step 5 Preview |
| Code migration (Vals AI) | 6.8% | 39.0% | Step 5 Preview |
| ProgramBench (Vals AI) | 0.0% | Not measured | Only Grok 4.3 measured |
| IOI (Vals AI) | Not measured | 38.1% | Only Step 5 Preview measured |
| Terminal-Bench 2.1 (Vals AI) | 42.0% | Not measured | Only Grok 4.3 measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 40.8% | Only Step 5 Preview measured |
| SkillsBench (Vals AI) | 40.6% | Not measured | Only Grok 4.3 measured |
| SciCode | 48.3% | 58.9% | Step 5 Preview |
| Terminal-Bench Hard (Artificial Analysis run) | 37.9% | Not measured | Only Grok 4.3 measured |
| WeirdML | 49.9% | Not measured | Only Grok 4.3 measured |
| ALE-Bench | 944.2 | Not measured | Only Grok 4.3 measured |
| LMArena Text: coding | 1415 | 1485 | Step 5 Preview |
| LMArena Text: software and IT | 1416 | 1473 | Step 5 Preview |
| LMArena WebDev: React | 1353 | 1583 | Step 5 Preview |
| LMArena WebDev: HTML | 1367 | 1556 | Step 5 Preview |
| LMArena WebDev: from an image | 1375 | 1550 | Step 5 Preview |
| Neither model has a result on the other 16 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 24.9 | 43.7 | 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 index04
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| AA Agentic Index | 15.5 | Not measured | Only Grok 4.3 measured |
| Design Arena: agents building web apps | 1126 | Not measured | Only Grok 4.3 measured |
| Design Arena: agents building full-stack apps | 1006 | Not measured | Only Grok 4.3 measured |
| Design Arena: agents building mobile apps | 1059 | Not measured | Only Grok 4.3 measured |
| Design Arena: agents building Android apps | 967 | Not measured | Only Grok 4.3 measured |
| Design Arena: agents building Godot games | 914 | Not measured | Only Grok 4.3 measured |
| Design Arena: agents building games | 1007 | Not measured | Only Grok 4.3 measured |
| Design Arena: HTML slides | 1008 | Not measured | Only Grok 4.3 measured |
| Design Arena: PowerPoint slides | 1012 | Not measured | Only Grok 4.3 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) | 37.7% | 50.7% | Step 5 Preview |
| Tax Agent Bench (Vals AI) | 6.2% | 27.3% | Step 5 Preview |
| Legal Research Bench (Vals AI) | 15.4% | 40.4% | Step 5 Preview |
| Excel Modeling Benchmark (Vals AI) | 18.4% | 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 | 97.7% | Not measured | Only Grok 4.3 measured |
| Vending-Bench 2 | $35 | Not measured | Only Grok 4.3 measured |
| LMArena Search | 1166 | Not measured | Only Grok 4.3 measured |
| Neither model has a result on the other 16 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| GPQA Diamond | 91.4% | Not measured | Only Grok 4.3 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) | 83.1% | Not measured | Only Grok 4.3 measured |
| GPQA Diamond (Artificial Analysis run) | 90.1% | Not measured | Only Grok 4.3 measured |
| Humanity's Last Exam (Artificial Analysis run) | 37.2% | 46.5% | Step 5 Preview |
| GPQA Diamond (Epoch AI run) | 88.8% | Not measured | Only Grok 4.3 measured |
| Chess puzzles | 18.0% | Not measured | Only Grok 4.3 measured |
| LMArena Text: hard prompts | 1396 | 1461 | Step 5 Preview |
| LMArena Text: expert | 1384 | 1485 | Step 5 Preview |
| LMArena Text: hard prompts in English | 1402 | 1454 | Step 5 Preview |
| LMArena Vision: diagrams | 1241 | 1308 | Step 5 Preview |
| LMArena Vision: homework | 1241 | 1265 | Step 5 Preview |
| Neither model has a result on the other 8 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index03
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| OTIS Mock AIME | 93.3% | Not measured | Only Grok 4.3 measured |
| FrontierMath, tiers 1 to 3 | 42.8% | Not measured | Only Grok 4.3 measured |
| FrontierMath, tier 4 | 14.6% | Not measured | Only Grok 4.3 measured |
| ProofBench | 11.0% | 42.0% | Step 5 Preview |
| LMArena Text: math | 1387 | 1458 | Step 5 Preview |
| LMArena Text: mathematical work | 1396 | 1460 | Step 5 Preview |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index04
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| MMLU Pro | 85.8% | Not measured | Only Grok 4.3 measured |
| LegalBench (Vals AI) | 84.5% | Not measured | Only Grok 4.3 measured |
| CaseLaw (Vals AI) | 79.3% | Not measured | Only Grok 4.3 measured |
| CorpFin (Vals AI) | 68.5% | Not measured | Only Grok 4.3 measured |
| TaxEval (Vals AI) | 70.8% | Not measured | Only Grok 4.3 measured |
| MortgageTax (Vals AI) | 48.3% | Not measured | Only Grok 4.3 measured |
| MedCode (Vals AI) | 38.1% | Not measured | Only Grok 4.3 measured |
| SimpleQA Verified | 33.2% | Not measured | Only Grok 4.3 measured |
| LMArena Text: science | 1399 | 1454 | Step 5 Preview |
| LMArena Text: medicine and healthcare | 1384 | 1439 | Step 5 Preview |
| LMArena Text: legal and government | 1386 | 1437 | Step 5 Preview |
| LMArena Text: business and finance | 1381 | 1435 | Step 5 Preview |
| Neither model has a result on the other 5 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1196 | Not measured | Only Grok 4.3 measured |
| Design Arena: UI components | 1192 | Not measured | Only Grok 4.3 measured |
| Design Arena: game dev | 1174 | Not measured | Only Grok 4.3 measured |
| Design Arena: data viz | 1180 | Not measured | Only Grok 4.3 measured |
| Design Arena: 3D | 1125 | Not measured | Only Grok 4.3 measured |
| Design Arena: all code categories | 1187 | Not measured | Only Grok 4.3 measured |
| Design Arena: SVG | 1081 | Not measured | Only Grok 4.3 measured |
| Design Arena: ASCII art | 1125 | Not measured | Only Grok 4.3 measured |
| LiveBench design | Not measured | 76.9% | Only Step 5 Preview measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index019
| Benchmark | Grok 4.3 | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench data analysis | Not measured | 63.5% | Only Step 5 Preview measured |
| Public Benefits Bench (Vals AI) | 51.7% | 58.1% | Step 5 Preview |
| SAGE (Vals AI) | 19.7% | Not measured | Only Grok 4.3 measured |
| MedScribe (Vals AI) | 74.4% | Not measured | Only Grok 4.3 measured |
| Vals Multimodal Index | 43.3% | Not measured | Only Grok 4.3 measured |
| IFBench | 83.3% | Not measured | Only Grok 4.3 measured |
| Long context reasoning (AA-LCR) | 75.0% | 88.3% | Step 5 Preview |
| DTBench | 90.7% | Not measured | Only Grok 4.3 measured |
| LMCA | 38.3% | Not measured | Only Grok 4.3 measured |
| LMArena Text | 1397 | 1440 | Step 5 Preview |
| LMArena Text: instruction following | 1366 | 1438 | Step 5 Preview |
| LMArena Text: creative writing | 1380 | 1409 | Step 5 Preview |
| LMArena Vision | 1229 | 1265 | Step 5 Preview |
| LMArena Text: English | 1404 | 1447 | Step 5 Preview |
| LMArena Text: non-English | 1385 | 1428 | Step 5 Preview |
| LMArena Text: Chinese | 1422 | 1500 | Step 5 Preview |
| LMArena Text: German | 1395 | Not measured | Only Grok 4.3 measured |
| LMArena Text: Japanese | 1379 | 1383 | Step 5 Preview |
| LMArena Text: Korean | 1354 | Not measured | Only Grok 4.3 measured |
| LMArena Text: French | 1411 | 1438 | Step 5 Preview |
| LMArena Text: Spanish | 1399 | 1441 | Step 5 Preview |
| LMArena Text: Russian | 1399 | 1433 | Step 5 Preview |
| LMArena Text: Polish | 1398 | Not measured | Only Grok 4.3 measured |
| LMArena Text: multi-turn | 1406 | 1437 | Step 5 Preview |
| LMArena Text: longer queries | 1393 | 1449 | Step 5 Preview |
| LMArena Text: writing and language | 1385 | 1425 | Step 5 Preview |
| LMArena Text: entertainment and media | 1370 | 1412 | Step 5 Preview |
| LMArena Vision: English | 1235 | 1290 | Step 5 Preview |
| LMArena Vision: Chinese | 1257 | Not measured | Only Grok 4.3 measured |
| LMArena Vision: reading text | 1235 | 1282 | Step 5 Preview |
| LMArena Vision: humor | 1222 | Not measured | Only Grok 4.3 measured |
| LMArena Vision: recognizing things | 1217 | Not measured | Only Grok 4.3 measured |
| LMArena Vision: creative writing | 1237 | Not measured | Only Grok 4.3 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 | Grok 4.3 | 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 | SpaceXAI Grok 4.3 | StepFun Step 5 Preview |
|---|---|---|
| Maker | xAI | StepFun |
| Weights | No public weights listed | Open weights |
| Released | April 30, 2026 | October 8, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $1.25 | $1.00 |
| Output $/Mtok | $2.50 | $2.70 |
| Coding index | 22.5 | 71.4 |
| Independent measurements behind it | 1 | 2 |
| Cost per solved task | $0.31 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Grok 4.3 better than Step 5 Preview for coding?
Pick Step 5 Preview for coding: it scores 71.4 on the Vibe Coding Index against 22.5 for Grok 4.3. Pick Grok 4.3 when output tokens cost 1.1x less.
Which is cheaper, Grok 4.3 or Step 5 Preview?
Grok 4.3 costs $1.25 per million input tokens and $2.50 per million output tokens; Step 5 Preview costs $1.00 and $2.70. Cost per solved task is known for Grok 4.3 only.
Which has the bigger context window, Grok 4.3 or Step 5 Preview?
Step 5 Preview, with 1.05M tokens against 1M.
How many benchmarks is the Grok 4.3 vs Step 5 Preview comparison based on?
46 benchmarks have a result for both models as of October 21, 2026. Grok 4.3's coding index rests on 1 independent benchmark and Step 5 Preview's on 2. Where only one model has a result, the page says so instead of naming a winner.