GPT-5.6 Sol vs Grok 4.3
GPT-5.6 Sol leads Grok 4.3 on coding, 73.5 to 37.4 on the Vibe Coding Index, and Grok 4.3 costs 8.0x less per output token ($2.50 vs $20.00 per million). Updated October 22, 2026; 102 benchmarks have a result for both.
GPT-5.6 Sol or Grok 4.3: which to pick
Pick GPT-5.6 Sol for coding: it scores 73.5 on the Vibe Coding Index against 37.4 for Grok 4.3.
Pick Grok 4.3 for output tokens 8.0x cheaper ($2.50 vs $20.00 per million) and a lower cost per solved task ($0.31 against $1.20).
- Shared results
- 102
- GPT-5.6 Sol only
- 37
- Grok 4.3 only
- 3
- Like-for-like categories
- 8 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
GPT-5.6 Sol
GPT-5.6 Sol scores 73.5 against 37.4.
6 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-5.6 Sol
GPT-5.6 Sol leads, 47.0 against 24.9.
Same board, both measured
Agentic work
AA Agentic Index
GPT-5.6 Sol
GPT-5.6 Sol leads, 50.2 against 15.5.
Same board, both measured
Reasoning
GPQA Diamond
GPT-5.6 Sol
GPT-5.6 Sol leads, 95.2% against 91.4%.
Same board, both measured
Knowledge
MMLU Pro
GPT-5.6 Sol
GPT-5.6 Sol leads, 89.1% against 85.8%.
Same board, both measured
Web design
Design Arena: websites
GPT-5.6 Sol
GPT-5.6 Sol leads, 1321 against 1196.
Same board, both measured
Long documents
Listed context window
GPT-5.6 Sol
GPT-5.6 Sol takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Grok 4.3
GPT-5.6 Sol $0.014, Grok 4.3 $0.0025 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Grok 4.3
GPT-5.6 Sol $1.20, Grok 4.3 $0.31.
Published attempt cost and pass rate
At a glance
- Coding index
- GPT-5.6 Sol 73.5 from 6 benchmarks, Grok 4.3 37.4 from 3 benchmarks.
- Widest category
- Math, 37.4 points apart on average over 6 shared benchmarks.
- Widest single gap
- ProofBench: GPT-5.6 Sol 83.0% against Grok 4.3 11.0%, 72.0 points apart on a 0 to 100 scale.
- Output price
- GPT-5.6 Sol $20.00 against Grok 4.3 $2.50 per million output tokens, 8.0x apart.
- Context window
- GPT-5.6 Sol takes 1.05M tokens, Grok 4.3 1M.
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 | GPT-5.6 Sol | Bars | Grok 4.3 | Ties |
|---|---|---|---|---|
| Coding | 17 | 1 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 15 | 1 | ||
| Reasoning | 11 | 0 | ||
| Math | 6 | 0 | ||
| Knowledge | 10 | 1 | ||
| Web design | 8 | 0 | ||
| General | 30 | 1 | ||
| All shared boards | 98 | 4 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index171
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| LiveBench coding | 89.7% | Not measured | Only GPT-5.6 Sol measured |
| LMArena WebDev | 1616 | 1358 | GPT-5.6 Sol |
| AA Coding Index | 77.4 | 42.2 | GPT-5.6 Sol |
| LiveCodeBench (Vals AI) | 82.6% | 84.5% | Grok 4.3 |
| SWE-bench Verified (Vals AI) | 96.2% | 71.4% | GPT-5.6 Sol |
| Terminal-Bench 4 (Vals AI) | 37.9% | Not measured | Only GPT-5.6 Sol measured |
| Vibe Code Bench (Vals AI) | 80.5% | 19.4% | GPT-5.6 Sol |
| Code migration (Vals AI) | 52.9% | 6.8% | GPT-5.6 Sol |
| ProgramBench (Vals AI) | 1.5% | 0.0% | GPT-5.6 Sol |
| IOI (Vals AI) | 91.2% | Not measured | Only GPT-5.6 Sol measured |
| Terminal-Bench 2.1 (Vals AI) | 85.8% | 42.0% | GPT-5.6 Sol |
| Vibe Code Bench 1-100 (Vals AI) | 20.0% | Not measured | Only GPT-5.6 Sol measured |
| SkillsBench (Vals AI) | 54.1% | 40.6% | GPT-5.6 Sol |
| CyberBench (Vals AI) | 76.3% | Not measured | Only GPT-5.6 Sol measured |
| SciCode | 57.8% | 48.3% | GPT-5.6 Sol |
| Terminal-Bench Hard (Artificial Analysis run) | 65.9% | 37.9% | GPT-5.6 Sol |
| FrontierCode | 47.5% | Not measured | Only GPT-5.6 Sol measured |
| FrontierSWE | 32.2% | Not measured | Only GPT-5.6 Sol measured |
| GSO-Bench | 76.5% | Not measured | Only GPT-5.6 Sol measured |
| WeirdML | 88.8% | 49.9% | GPT-5.6 Sol |
| MirrorCode | 20.0% | Not measured | Only GPT-5.6 Sol measured |
| ALE-Bench | 2176.9 | 944.2 | GPT-5.6 Sol |
| LMArena Text: coding | 1496 | 1415 | GPT-5.6 Sol |
| LMArena Text: software and IT | 1489 | 1416 | GPT-5.6 Sol |
| LMArena WebDev: React | 1620 | 1353 | GPT-5.6 Sol |
| LMArena WebDev: HTML | 1618 | 1367 | GPT-5.6 Sol |
| LMArena WebDev: from an image | 1609 | 1375 | GPT-5.6 Sol |
| SciCode | 10.8% | Not measured | Only GPT-5.6 Sol measured |
| Neither model has a result on the other 11 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| AA Intelligence Index | 47.0 | 24.9 | GPT-5.6 Sol |
| Epoch Capabilities Index | 162.8 | Not measured | Only GPT-5.6 Sol measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index151
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| AA Agentic Index | 50.2 | 15.5 | GPT-5.6 Sol |
| Design Arena: agents building web apps | 1245 | 1126 | GPT-5.6 Sol |
| Design Arena: agents building full-stack apps | 1261 | 1006 | GPT-5.6 Sol |
| Design Arena: agents building mobile apps | 1248 | 1058 | GPT-5.6 Sol |
| Design Arena: agents building Android apps | 1240 | 962 | GPT-5.6 Sol |
| Design Arena: agents building Godot games | 1260 | 914 | GPT-5.6 Sol |
| Design Arena: agents building games | 1266 | 1007 | GPT-5.6 Sol |
| Design Arena: HTML slides | 1236 | 959 | GPT-5.6 Sol |
| Design Arena: PowerPoint slides | 1215 | 988 | GPT-5.6 Sol |
| Design Arena: spreadsheets | Not measured | 879 | Only Grok 4.3 measured |
| LiveBench research | 54.5% | Not measured | Only GPT-5.6 Sol measured |
| LiveBench browser | 88.0% | Not measured | Only GPT-5.6 Sol measured |
| LiveBench long agentic | 48.5% | Not measured | Only GPT-5.6 Sol measured |
| SREBench (Vals AI) | 30.5% | Not measured | Only GPT-5.6 Sol measured |
| Finance Agent (Vals AI) | 53.8% | 37.7% | GPT-5.6 Sol |
| Tax Agent Bench (Vals AI) | 31.1% | 6.2% | GPT-5.6 Sol |
| Legal Research Bench (Vals AI) | 48.1% | 15.4% | GPT-5.6 Sol |
| Excel Modeling Benchmark (Vals AI) | 72.3% | 18.4% | GPT-5.6 Sol |
| BioMysteryBench (Vals AI) | 71.1% | Not measured | Only GPT-5.6 Sol measured |
| Terminal-Bench-Science (Vals AI) | 20.0% | Not measured | Only GPT-5.6 Sol measured |
| Vals Science Index | 41.5% | Not measured | Only GPT-5.6 Sol measured |
| Time Horizon Index (Vals AI) | 23.8% | Not measured | Only GPT-5.6 Sol measured |
| CUA-bench (Vals AI) | 8.3% | Not measured | Only GPT-5.6 Sol measured |
| τ²-Bench Telecom | 85.1% | 97.7% | Grok 4.3 |
| OSWorld 2.0 | 27.3% | Not measured | Only GPT-5.6 Sol measured |
| BALROG | 60.0% | Not measured | Only GPT-5.6 Sol measured |
| PostTrainBench | 36.2% | Not measured | Only GPT-5.6 Sol measured |
| Vending-Bench 2 | $9,619 | $35 | GPT-5.6 Sol |
| LMArena Search | 1261 | 1166 | GPT-5.6 Sol |
| Neither model has a result on the other 12 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index110
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| GPQA Diamond | 95.2% | 91.4% | GPT-5.6 Sol |
| LiveBench reasoning | 91.7% | Not measured | Only GPT-5.6 Sol measured |
| MysteryMechanism (Vals AI) | 33.3% | Not measured | Only GPT-5.6 Sol measured |
| MMMU Pro (Vals AI) | 88.8% | 83.1% | GPT-5.6 Sol |
| GPQA Diamond (Artificial Analysis run) | 94.1% | 90.1% | GPT-5.6 Sol |
| Humanity's Last Exam (Artificial Analysis run) | 49.5% | 37.2% | GPT-5.6 Sol |
| GPQA Diamond (Epoch AI run) | 93.5% | 88.8% | GPT-5.6 Sol |
| ARC-AGI | 97.5% | Not measured | Only GPT-5.6 Sol measured |
| ARC-AGI-2 | 92.5% | Not measured | Only GPT-5.6 Sol measured |
| SimpleBench | 64.8% | Not measured | Only GPT-5.6 Sol measured |
| Chess puzzles | 59.0% | 18.0% | GPT-5.6 Sol |
| Mystery game puzzles | 58.0% | Not measured | Only GPT-5.6 Sol measured |
| EBR-bench | 44.8% | Not measured | Only GPT-5.6 Sol measured |
| LMArena Text: hard prompts | 1483 | 1396 | GPT-5.6 Sol |
| LMArena Text: expert | 1517 | 1384 | GPT-5.6 Sol |
| LMArena Text: hard prompts in English | 1477 | 1402 | GPT-5.6 Sol |
| LMArena Vision: diagrams | 1305 | 1241 | GPT-5.6 Sol |
| LMArena Vision: homework | 1305 | 1241 | GPT-5.6 Sol |
| Kagi LLM Benchmark | 67.0% | Not measured | Only GPT-5.6 Sol measured |
| Neither model has a result on the other 3 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | 93.3% | GPT-5.6 Sol |
| FrontierMath, tiers 1 to 3 | 89.1% | 42.8% | GPT-5.6 Sol |
| FrontierMath, tier 4 | 82.9% | 14.6% | GPT-5.6 Sol |
| ProofBench | 83.0% | 11.0% | GPT-5.6 Sol |
| LMArena Text: math | 1473 | 1387 | GPT-5.6 Sol |
| LMArena Text: mathematical work | 1496 | 1396 | GPT-5.6 Sol |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index101
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| MMLU Pro | 89.1% | 85.8% | GPT-5.6 Sol |
| LegalBench (Vals AI) | 87.0% | 84.5% | GPT-5.6 Sol |
| CaseLaw (Vals AI) | Not measured | 79.3% | Only Grok 4.3 measured |
| CorpFin (Vals AI) | 64.4% | 68.5% | Grok 4.3 |
| TaxEval (Vals AI) | 74.8% | 70.8% | GPT-5.6 Sol |
| MortgageTax (Vals AI) | 67.3% | 48.3% | GPT-5.6 Sol |
| MedCode (Vals AI) | 44.0% | 38.1% | GPT-5.6 Sol |
| SimpleQA Verified | 69.7% | 33.2% | GPT-5.6 Sol |
| LMArena Text: science | 1455 | 1399 | GPT-5.6 Sol |
| LMArena Text: medicine and healthcare | 1431 | 1384 | GPT-5.6 Sol |
| LMArena Text: legal and government | 1476 | 1386 | GPT-5.6 Sol |
| LMArena Text: business and finance | 1457 | 1381 | GPT-5.6 Sol |
| FACTS Benchmark Suite | 52.4% | Not measured | Only GPT-5.6 Sol measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| Design Arena: websites | 1321 | 1196 | GPT-5.6 Sol |
| Design Arena: UI components | 1335 | 1190 | GPT-5.6 Sol |
| Design Arena: game dev | 1367 | 1173 | GPT-5.6 Sol |
| Design Arena: data viz | 1322 | 1179 | GPT-5.6 Sol |
| Design Arena: 3D | 1384 | 1124 | GPT-5.6 Sol |
| Design Arena: all code categories | 1341 | 1186 | GPT-5.6 Sol |
| Design Arena: SVG | 1314 | 1080 | GPT-5.6 Sol |
| Design Arena: ASCII art | 1304 | 1125 | GPT-5.6 Sol |
| LiveBench design | 81.6% | Not measured | Only GPT-5.6 Sol measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index301
| Benchmark | GPT-5.6 Sol | Grok 4.3 | Leader |
|---|---|---|---|
| LiveBench data analysis | 79.8% | Not measured | Only GPT-5.6 Sol measured |
| Public Benefits Bench (Vals AI) | 66.5% | 51.7% | GPT-5.6 Sol |
| SAGE (Vals AI) | 52.6% | 19.7% | GPT-5.6 Sol |
| MedScribe (Vals AI) | 85.2% | 74.4% | GPT-5.6 Sol |
| Vals Multimodal Index | 72.6% | 43.3% | GPT-5.6 Sol |
| IFBench | 72.7% | 83.3% | Grok 4.3 |
| Long context reasoning (AA-LCR) | 84.0% | 75.0% | GPT-5.6 Sol |
| DTBench | 95.7% | 90.7% | GPT-5.6 Sol |
| LMCA | 58.5% | 38.3% | GPT-5.6 Sol |
| Surface Evolver Bench | 93.1% | Not measured | Only GPT-5.6 Sol measured |
| Furniture assembly | 56.7% | Not measured | Only GPT-5.6 Sol measured |
| LMArena Text | 1457 | 1397 | GPT-5.6 Sol |
| LMArena Text: instruction following | 1483 | 1366 | GPT-5.6 Sol |
| LMArena Text: creative writing | 1449 | 1380 | GPT-5.6 Sol |
| LMArena Vision | 1281 | 1229 | GPT-5.6 Sol |
| LMArena Text: English | 1457 | 1404 | GPT-5.6 Sol |
| LMArena Text: non-English | 1451 | 1385 | GPT-5.6 Sol |
| LMArena Text: Chinese | 1525 | 1422 | GPT-5.6 Sol |
| LMArena Text: German | 1476 | 1395 | GPT-5.6 Sol |
| LMArena Text: Japanese | 1472 | 1379 | GPT-5.6 Sol |
| LMArena Text: Korean | 1442 | 1354 | GPT-5.6 Sol |
| LMArena Text: French | 1472 | 1411 | GPT-5.6 Sol |
| LMArena Text: Spanish | 1443 | 1399 | GPT-5.6 Sol |
| LMArena Text: Russian | 1471 | 1399 | GPT-5.6 Sol |
| LMArena Text: Polish | 1459 | 1398 | GPT-5.6 Sol |
| LMArena Text: multi-turn | 1461 | 1406 | GPT-5.6 Sol |
| LMArena Text: longer queries | 1481 | 1393 | GPT-5.6 Sol |
| LMArena Text: writing and language | 1462 | 1385 | GPT-5.6 Sol |
| LMArena Text: entertainment and media | 1450 | 1370 | GPT-5.6 Sol |
| LMArena Vision: English | 1280 | 1235 | GPT-5.6 Sol |
| LMArena Vision: Chinese | 1313 | 1257 | GPT-5.6 Sol |
| LMArena Vision: reading text | 1290 | 1235 | GPT-5.6 Sol |
| LMArena Vision: humor | 1246 | 1222 | GPT-5.6 Sol |
| LMArena Vision: recognizing things | Not measured | 1217 | Only Grok 4.3 measured |
| LMArena Vision: creative writing | 1283 | 1237 | GPT-5.6 Sol |
| LMArena Document | 1483 | Not measured | Only GPT-5.6 Sol measured |
| Neither model has a result on the other 10 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5.6 Sol | Grok 4.3 | 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
Grok 4.3 costs less
Repository review
50K input + 3K output tokens
Grok 4.3 costs less
Agent loop
200K input + 10K output tokens
Grok 4.3 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 GPT-5.6 Sol | SpaceXAI Grok 4.3 |
|---|---|---|
| Maker | OpenAI | xAI |
| Weights | No public weights listed | No public weights listed |
| Released | July 9, 2026 | April 30, 2026 |
| Context window | 1.05M | 1M |
| Input $/Mtok | $4.00 | $1.25 |
| Output $/Mtok | $20.00 | $2.50 |
| Coding index | 73.5 | 37.4 |
| Independent measurements behind it | 6 | 3 |
| Cost per solved task | $1.20 | $0.31 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.6 Sol better than Grok 4.3 for coding?
Pick GPT-5.6 Sol for coding: it scores 73.5 on the Vibe Coding Index against 37.4 for Grok 4.3. Pick Grok 4.3 for output tokens 8.0x cheaper ($2.50 vs $20.00 per million) and a lower cost per solved task ($0.31 against $1.20).
Which is cheaper, GPT-5.6 Sol or Grok 4.3?
GPT-5.6 Sol costs $4.00 per million input tokens and $20.00 per million output tokens; Grok 4.3 costs $1.25 and $2.50. Per solved SWE-bench Verified task, GPT-5.6 Sol costs $1.20 and Grok 4.3 $0.31.
Which has the bigger context window, GPT-5.6 Sol or Grok 4.3?
GPT-5.6 Sol, with 1.05M tokens against 1M.
How many benchmarks is the GPT-5.6 Sol vs Grok 4.3 comparison based on?
102 benchmarks have a result for both models as of October 22, 2026. GPT-5.6 Sol's coding index rests on 6 independent benchmarks and Grok 4.3's on 3. Where only one model has a result, the page says so instead of naming a winner.