Claude Sonnet 5.5 vs GPT-6 Sol
Claude Sonnet 5.5 leads GPT-6 Sol on coding, 87.3 to 76.0 on the Vibe Coding Index, at about the same output price ($10.00 vs $10.00 per million). Updated October 21, 2026; 90 benchmarks have a result for both.
Claude Sonnet 5.5 or GPT-6 Sol: which to pick
Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 76.0 for GPT-6 Sol.
Pick GPT-6 Sol for a larger context window (1.05M against 1M tokens) and work measured by CyberBench (Vals AI) or ALE-Bench, where it leads.
- Shared results
- 90
- Claude Sonnet 5.5 only
- 6
- GPT-6 Sol only
- 11
- 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
Claude Sonnet 5.5
Claude Sonnet 5.5 scores 87.3 against 76.0.
5 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 56.0 against 47.6.
Same board, both measured
Web design
Design Arena: websites
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 1326 against 1292.
Same board, both measured
General
Vals Index
No call
Only Claude Sonnet 5.5 has a Vals Index result, 70.8%.
Directional only
Long documents
Listed context window
GPT-6 Sol
GPT-6 Sol takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
No call
Claude Sonnet 5.5 $0.0070, GPT-6 Sol $0.0070 per turn.
List prices
At a glance
- Coding index
- Claude Sonnet 5.5 87.3 from 5 benchmarks, GPT-6 Sol 76.0 from 5 benchmarks.
- Widest category
- Knowledge, 13.5 points apart on average over 6 shared benchmarks.
- Widest single gap
- Tax Agent Bench (Vals AI): Claude Sonnet 5.5 42.0% against GPT-6 Sol 15.0%, 27.0 points apart on a 0 to 100 scale.
- Output price
- Both cost $10.00 per million output tokens.
- Context window
- Claude Sonnet 5.5 takes 1M tokens, GPT-6 Sol 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 | Claude Sonnet 5.5 | Bars | GPT-6 Sol | Ties |
|---|---|---|---|---|
| Coding | 14 | 2 | 1 tie | |
| Intelligence | 2 | 0 | ||
| Agentic work | 12 | 4 | ||
| Reasoning | 11 | 0 | ||
| Math | 3 | 2 | 1 tie | |
| Knowledge | 5 | 1 | ||
| Web design | 7 | 0 | ||
| General | 22 | 2 | 1 tie | |
| All shared boards | 76 | 11 | 3 ties |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index142
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| LiveBench coding | 94.7% | 93.1% | Claude Sonnet 5.5 |
| LMArena WebDev | 1768 | 1683 | Claude Sonnet 5.5 |
| Terminal-Bench 4 (Vals AI) | 64.1% | 44.4% | Claude Sonnet 5.5 |
| Vibe Code Bench (Vals AI) | 92.4% | 87.8% | Claude Sonnet 5.5 |
| Code migration (Vals AI) | 69.8% | 57.2% | Claude Sonnet 5.5 |
| ProgramBench (Vals AI) | 6.5% | 2.0% | Claude Sonnet 5.5 |
| IOI (Vals AI) | 83.1% | 82.6% | Claude Sonnet 5.5 |
| Terminal-Bench 2.1 (Vals AI) | 83.2% | 83.2% | Tie |
| SWE-bench Multimodal (Vals AI) | 58.3% | Not measured | Only Claude Sonnet 5.5 measured |
| CyberBench (Vals AI) | 59.6% | 78.0% | GPT-6 Sol |
| SciCode | 61.0% | 57.6% | Claude Sonnet 5.5 |
| FrontierCode | 52.1% | 49.3% | Claude Sonnet 5.5 |
| FrontierSWE | 61.9% | Not measured | Only Claude Sonnet 5.5 measured |
| ALE-Bench | 1819.1 | 2462.0 | GPT-6 Sol |
| LMArena Text: coding | 1513 | 1448 | Claude Sonnet 5.5 |
| LMArena Text: software and IT | 1504 | 1433 | Claude Sonnet 5.5 |
| LMArena WebDev: React | 1817 | 1685 | Claude Sonnet 5.5 |
| LMArena WebDev: HTML | 1741 | 1685 | Claude Sonnet 5.5 |
| LMArena WebDev: from an image | 1737 | 1660 | Claude Sonnet 5.5 |
| SciCode | 13.8% | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 19 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| AA Intelligence Index | 56.0 | 47.6 | Claude Sonnet 5.5 |
| Epoch Capabilities Index | 166.2 | 163.7 | Claude Sonnet 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index124
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1306 | 1231 | Claude Sonnet 5.5 |
| Design Arena: agents building full-stack apps | Not measured | 1238 | Only GPT-6 Sol measured |
| Design Arena: agents building mobile apps | 1257 | 1214 | Claude Sonnet 5.5 |
| Design Arena: spreadsheets | 1244 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench research | 83.6% | 69.3% | Claude Sonnet 5.5 |
| LiveBench browser | 84.0% | 92.0% | GPT-6 Sol |
| LiveBench long agentic | 78.8% | 66.9% | Claude Sonnet 5.5 |
| SREBench (Vals AI) | 30.1% | 30.5% | GPT-6 Sol |
| Finance Agent (Vals AI) | 58.1% | 49.0% | Claude Sonnet 5.5 |
| Tax Agent Bench (Vals AI) | 42.0% | 15.0% | Claude Sonnet 5.5 |
| Legal Research Bench (Vals AI) | 48.1% | 28.9% | Claude Sonnet 5.5 |
| Harvey's Legal Agent Benchmark (Vals AI) | 10.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 75.7% | 71.5% | Claude Sonnet 5.5 |
| BioMysteryBench (Vals AI) | 81.1% | 74.8% | Claude Sonnet 5.5 |
| Terminal-Bench-Science (Vals AI) | 47.1% | 30.0% | Claude Sonnet 5.5 |
| Vals Science Index | 59.1% | 45.0% | Claude Sonnet 5.5 |
| APEX-Agents | 75.5% | 54.3% | Claude Sonnet 5.5 |
| SpireClimb | 1.3% | 7.5% | GPT-6 Sol |
| Vending-Bench 2 | $11,165 | $14,428 | GPT-6 Sol |
| Neither model has a result on the other 22 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index110
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| LiveBench reasoning | 91.6% | 88.7% | Claude Sonnet 5.5 |
| MysteryMechanism (Vals AI) | 49.1% | 30.2% | Claude Sonnet 5.5 |
| Humanity's Last Exam (Artificial Analysis run) | 55.0% | 47.9% | Claude Sonnet 5.5 |
| GPQA Diamond (Epoch AI run) | 95.6% | 94.3% | Claude Sonnet 5.5 |
| ARC-AGI | Not measured | 95.5% | Only GPT-6 Sol measured |
| ARC-AGI-2 | Not measured | 89.6% | Only GPT-6 Sol measured |
| Chess puzzles | 59.0% | 56.0% | Claude Sonnet 5.5 |
| Mystery game puzzles | 65.0% | 56.0% | Claude Sonnet 5.5 |
| EBR-bench | Not measured | 53.3% | Only GPT-6 Sol measured |
| LMArena Text: hard prompts | 1494 | 1422 | Claude Sonnet 5.5 |
| LMArena Text: expert | 1531 | 1437 | Claude Sonnet 5.5 |
| LMArena Text: hard prompts in English | 1502 | 1420 | Claude Sonnet 5.5 |
| LMArena Vision: diagrams | 1329 | 1270 | Claude Sonnet 5.5 |
| LMArena Vision: homework | 1331 | 1286 | Claude Sonnet 5.5 |
| Neither model has a result on the other 8 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index32
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | 100.0% | Tie |
| FrontierMath, tiers 1 to 3 | 88.8% | 89.8% | GPT-6 Sol |
| FrontierMath, tier 4 | 80.5% | 90.0% | GPT-6 Sol |
| ProofBench | 100.0% | 83.0% | Claude Sonnet 5.5 |
| LMArena Text: math | 1497 | 1407 | Claude Sonnet 5.5 |
| LMArena Text: mathematical work | 1510 | 1424 | Claude Sonnet 5.5 |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index51
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| MedCode (Vals AI) | 52.9% | 47.1% | Claude Sonnet 5.5 |
| SimpleQA Verified | 46.5% | 60.7% | GPT-6 Sol |
| LMArena Text: science | 1483 | 1389 | Claude Sonnet 5.5 |
| LMArena Text: medicine and healthcare | 1464 | 1366 | Claude Sonnet 5.5 |
| LMArena Text: legal and government | 1483 | 1396 | Claude Sonnet 5.5 |
| LMArena Text: business and finance | 1468 | 1380 | Claude Sonnet 5.5 |
| FACTS Benchmark Suite | Not measured | 72.5% | Only GPT-6 Sol measured |
| Neither model has a result on the other 11 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| Design Arena: websites | 1326 | 1292 | Claude Sonnet 5.5 |
| Design Arena: UI components | 1365 | 1292 | Claude Sonnet 5.5 |
| Design Arena: game dev | 1469 | 1314 | Claude Sonnet 5.5 |
| Design Arena: data viz | 1394 | 1269 | Claude Sonnet 5.5 |
| Design Arena: 3D | 1452 | 1318 | Claude Sonnet 5.5 |
| Design Arena: all code categories | 1364 | 1301 | Claude Sonnet 5.5 |
| Design Arena: SVG | Not measured | 1316 | Only GPT-6 Sol measured |
| Design Arena: ASCII art | Not measured | 1225 | Only GPT-6 Sol measured |
| LiveBench design | 85.0% | 82.2% | Claude Sonnet 5.5 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index222
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | Leader |
|---|---|---|---|
| Vals Index | 70.8% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench data analysis | 59.5% | 81.2% | GPT-6 Sol |
| Public Benefits Bench (Vals AI) | 67.2% | 56.6% | Claude Sonnet 5.5 |
| SAGE (Vals AI) | 51.8% | 44.8% | Claude Sonnet 5.5 |
| MedScribe (Vals AI) | 91.1% | 82.0% | Claude Sonnet 5.5 |
| Long context reasoning (AA-LCR) | 82.7% | 83.7% | GPT-6 Sol |
| DTBench | 97.3% | 97.3% | Tie |
| LMCA | 68.3% | 59.1% | Claude Sonnet 5.5 |
| Furniture assembly | 75.0% | 58.3% | Claude Sonnet 5.5 |
| LMArena Text | 1473 | 1398 | Claude Sonnet 5.5 |
| LMArena Text: instruction following | 1492 | 1413 | Claude Sonnet 5.5 |
| LMArena Text: creative writing | 1467 | 1378 | Claude Sonnet 5.5 |
| LMArena Vision | 1287 | 1240 | Claude Sonnet 5.5 |
| LMArena Text: English | 1484 | 1396 | Claude Sonnet 5.5 |
| LMArena Text: non-English | 1456 | 1388 | Claude Sonnet 5.5 |
| LMArena Text: Chinese | 1535 | 1412 | Claude Sonnet 5.5 |
| LMArena Text: German | Not measured | 1379 | Only GPT-6 Sol measured |
| LMArena Text: Japanese | Not measured | 1377 | Only GPT-6 Sol measured |
| LMArena Text: Korean | Not measured | 1336 | Only GPT-6 Sol measured |
| LMArena Text: French | 1499 | 1399 | Claude Sonnet 5.5 |
| LMArena Text: Spanish | 1451 | 1387 | Claude Sonnet 5.5 |
| LMArena Text: Russian | 1454 | 1402 | Claude Sonnet 5.5 |
| LMArena Text: Polish | Not measured | 1372 | Only GPT-6 Sol measured |
| LMArena Text: multi-turn | 1465 | 1414 | Claude Sonnet 5.5 |
| LMArena Text: longer queries | 1495 | 1416 | Claude Sonnet 5.5 |
| LMArena Text: writing and language | 1474 | 1389 | Claude Sonnet 5.5 |
| LMArena Text: entertainment and media | 1461 | 1373 | Claude Sonnet 5.5 |
| LMArena Vision: English | 1289 | 1229 | Claude Sonnet 5.5 |
| LMArena Vision: reading text | 1297 | 1258 | Claude Sonnet 5.5 |
| LMArena Vision: creative writing | 1242 | 1219 | Claude Sonnet 5.5 |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5.5 | GPT-6 Sol | 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
Same cost
Repository review
50K input + 3K output tokens
Same cost
Agent loop
200K input + 10K output tokens
Same cost
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 | Anthropic Claude Sonnet 5.5 | OpenAI GPT-6 Sol |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 28, 2026 | September 22, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $2.00 | $2.00 |
| Output $/Mtok | $10.00 | $10.00 |
| Coding index | 87.3 | 76.0 |
| Independent measurements behind it | 5 | 5 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5.5 better than GPT-6 Sol for coding?
Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 76.0 for GPT-6 Sol. Pick GPT-6 Sol for a larger context window (1.05M against 1M tokens) and work measured by CyberBench (Vals AI) or ALE-Bench, where it leads.
Which is cheaper, Claude Sonnet 5.5 or GPT-6 Sol?
Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; GPT-6 Sol costs $2.00 and $10.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Sonnet 5.5 or GPT-6 Sol?
GPT-6 Sol, with 1.05M tokens against 1M.
How many benchmarks is the Claude Sonnet 5.5 vs GPT-6 Sol comparison based on?
90 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 5.5's coding index rests on 5 independent benchmarks and GPT-6 Sol's on 5. Where only one model has a result, the page says so instead of naming a winner.