Claude Opus 5.5 vs GPT-5.1
Claude Opus 5.5 leads GPT-5.1 on coding, 88.8 to 40.4 on the Vibe Coding Index, and GPT-5.1 costs 2.0x less per output token ($10.00 vs $20.00 per million). Updated October 22, 2026; 61 benchmarks have a result for both.
vs boards won of 61 shared
Claude Opus 5.5 or GPT-5.1: which to pick
Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 40.4 for GPT-5.1.
Pick GPT-5.1 for output tokens 2.0x cheaper ($10.00 vs $20.00 per million) and work measured by MedCode (Vals AI), where it leads.
Model AClaude Opus 5.5Anthropic88.8/1005 independent benchmarksNo cost per solved taskModel BGPT-5.1OpenAI40.4/1003 independent benchmarks$1.02 per solved task
- Shared results
- 61
- Claude Opus 5.5 only
- 48
- GPT-5.1 only
- 40
- 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 Opus 5.5
Claude Opus 5.5 scores 88.8 against 40.4.
5 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Opus 5.5
Claude Opus 5.5 leads, 57.6 against 24.7.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only GPT-5.1 has a GPQA Diamond result, 86.6%.
Directional only
Math
AIME
No call
Only GPT-5.1 has a AIME result, 93.3%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-5.1 has a MMLU Pro result, 86.4%.
Directional only
Web design
Design Arena: websites
Claude Opus 5.5
Claude Opus 5.5 leads, 1335 against 1187.
Same board, both measured
General
Vals Index
No call
Only Claude Opus 5.5 has a Vals Index result, 70.2%.
Directional only
Long documents
Listed context window
Claude Opus 5.5
Claude Opus 5.5 takes 1M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GPT-5.1
Claude Opus 5.5 $0.014, GPT-5.1 $0.0063 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.1 has the number, $1.02.
Directional only
At a glance
- Coding index
- Claude Opus 5.5 88.8 from 5 benchmarks, GPT-5.1 40.4 from 3 benchmarks.
- Widest category
- Agentic work, 48.5 points apart on average over 1 shared benchmark.
- Widest single gap
- ARC-AGI-2: Claude Opus 5.5 93.3% against GPT-5.1 17.6%, 75.7 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 5.5 $20.00 against GPT-5.1 $10.00 per million output tokens, 2.0x apart.
- Context window
- Claude Opus 5.5 takes 1M tokens, GPT-5.1 400K.
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 Opus 5.5 | Bars | GPT-5.1 | Ties |
|---|---|---|---|---|
| Coding | 7 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 1 | 0 | ||
| Reasoning | 11 | 0 | ||
| Math | 3 | 0 | ||
| Knowledge | 6 | 1 | ||
| Web design | 7 | 0 | ||
| General | 23 | 0 | ||
| All shared boards | 60 | 1 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index70
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 66.0% | Only GPT-5.1 measured |
| LiveBench coding | 96.3% | Not measured | Only Claude Opus 5.5 measured |
| LMArena WebDev | 1807 | 1396 | Claude Opus 5.5 |
| AA Coding Index | Not measured | 49.4 | Only GPT-5.1 measured |
| LiveCodeBench (Vals AI) | Not measured | 86.5% | Only GPT-5.1 measured |
| SWE-bench Verified (Vals AI) | Not measured | 69.8% | Only GPT-5.1 measured |
| Terminal-Bench 4 (Vals AI) | 65.2% | Not measured | Only Claude Opus 5.5 measured |
| Vibe Code Bench (Vals AI) | 90.3% | 24.6% | Claude Opus 5.5 |
| Code migration (Vals AI) | 66.7% | Not measured | Only Claude Opus 5.5 measured |
| ProgramBench (Vals AI) | 18.5% | Not measured | Only Claude Opus 5.5 measured |
| IOI (Vals AI) | 95.1% | Not measured | Only Claude Opus 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | 87.6% | Not measured | Only Claude Opus 5.5 measured |
| SWE-bench Multimodal (Vals AI) | 70.2% | Not measured | Only Claude Opus 5.5 measured |
| Vibe Code Bench 1-100 (Vals AI) | 30.4% | Not measured | Only Claude Opus 5.5 measured |
| CyberBench (Vals AI) | 74.6% | Not measured | Only Claude Opus 5.5 measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 86.8% | Only GPT-5.1 measured |
| SciCode | 66.9% | Not measured | Only Claude Opus 5.5 measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 45.5% | Only GPT-5.1 measured |
| Terminal-Bench | Not measured | 47.6% | Only GPT-5.1 measured |
| FrontierCode | 54.6% | Not measured | Only Claude Opus 5.5 measured |
| FrontierSWE | 62.3% | Not measured | Only Claude Opus 5.5 measured |
| GSO-Bench | Not measured | 13.7% | Only GPT-5.1 measured |
| WeirdML | Not measured | 60.8% | Only GPT-5.1 measured |
| MirrorCode | 77.4% | Not measured | Only Claude Opus 5.5 measured |
| ALE-Bench | 2147.4 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Text: coding | 1545 | 1453 | Claude Opus 5.5 |
| LMArena Text: software and IT | 1538 | 1454 | Claude Opus 5.5 |
| LMArena WebDev: React | 1855 | 1307 | Claude Opus 5.5 |
| LMArena WebDev: HTML | 1753 | 1405 | Claude Opus 5.5 |
| LMArena WebDev: from an image | 1753 | 1421 | Claude Opus 5.5 |
| SciCode | 18.5% | Not measured | Only Claude Opus 5.5 measured |
| Neither model has a result on the other 8 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| AA Intelligence Index | 57.6 | 24.7 | Claude Opus 5.5 |
| Epoch Capabilities Index | 168.8 | 149.8 | Claude Opus 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1316 | Not measured | Only Claude Opus 5.5 measured |
| Design Arena: agents building mobile apps | 1308 | Not measured | Only Claude Opus 5.5 measured |
| Design Arena: spreadsheets | 1368 | Not measured | Only Claude Opus 5.5 measured |
| LiveBench research | 85.0% | Not measured | Only Claude Opus 5.5 measured |
| LiveBench browser | 80.0% | Not measured | Only Claude Opus 5.5 measured |
| LiveBench long agentic | 85.0% | Not measured | Only Claude Opus 5.5 measured |
| SREBench (Vals AI) | 33.6% | Not measured | Only Claude Opus 5.5 measured |
| Finance Agent (Vals AI) | 58.6% | Not measured | Only Claude Opus 5.5 measured |
| Tax Agent Bench (Vals AI) | 45.6% | Not measured | Only Claude Opus 5.5 measured |
| Legal Research Bench (Vals AI) | 50.5% | Not measured | Only Claude Opus 5.5 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 9.2% | Not measured | Only Claude Opus 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 75.9% | Not measured | Only Claude Opus 5.5 measured |
| BioMysteryBench (Vals AI) | 79.3% | Not measured | Only Claude Opus 5.5 measured |
| Terminal-Bench-Science (Vals AI) | 47.1% | Not measured | Only Claude Opus 5.5 measured |
| Vals Science Index | 58.7% | Not measured | Only Claude Opus 5.5 measured |
| Time Horizon Index (Vals AI) | 91.3% | Not measured | Only Claude Opus 5.5 measured |
| CUA-bench (Vals AI) | 14.0% | Not measured | Only Claude Opus 5.5 measured |
| Robo-bench (Vals AI) | 14.6% | Not measured | Only Claude Opus 5.5 measured |
| τ²-Bench Telecom | Not measured | 81.9% | Only GPT-5.1 measured |
| APEX-Agents | 73.5% | Not measured | Only Claude Opus 5.5 measured |
| Remote Labor Index | 21.3% | Not measured | Only Claude Opus 5.5 measured |
| DeepResearch Bench | Not measured | 42.8% | Only GPT-5.1 measured |
| SpireClimb | 3.3% | Not measured | Only Claude Opus 5.5 measured |
| Vending-Bench 2 | $9,235 | $1,473 | Claude Opus 5.5 |
| LMArena Search | 1213 | Not measured | Only Claude Opus 5.5 measured |
| Neither model has a result on the other 16 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index110
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 86.6% | Only GPT-5.1 measured |
| LiveBench reasoning | 92.2% | Not measured | Only Claude Opus 5.5 measured |
| MysteryMechanism (Vals AI) | 49.5% | Not measured | Only Claude Opus 5.5 measured |
| MMMU Pro (Vals AI) | Not measured | 83.2% | Only GPT-5.1 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 87.3% | Only GPT-5.1 measured |
| Humanity's Last Exam (Artificial Analysis run) | 61.4% | 28.5% | Claude Opus 5.5 |
| GPQA Diamond (Epoch AI run) | 90.6% | 87.6% | Claude Opus 5.5 |
| ARC-AGI | 98.5% | 72.8% | Claude Opus 5.5 |
| ARC-AGI-2 | 93.3% | 17.6% | Claude Opus 5.5 |
| SimpleBench | Not measured | 53.2% | Only GPT-5.1 measured |
| Chess puzzles | 67.0% | 42.0% | Claude Opus 5.5 |
| Mystery game puzzles | 71.0% | 19.0% | Claude Opus 5.5 |
| EBR-bench | 71.4% | Not measured | Only Claude Opus 5.5 measured |
| VPCT | Not measured | 58.7% | Only GPT-5.1 measured |
| LMArena Text: hard prompts | 1536 | 1457 | Claude Opus 5.5 |
| LMArena Text: expert | 1549 | 1470 | Claude Opus 5.5 |
| LMArena Text: hard prompts in English | 1535 | 1462 | Claude Opus 5.5 |
| LMArena Vision: diagrams | 1345 | 1264 | Claude Opus 5.5 |
| LMArena Vision: homework | 1362 | 1272 | Claude Opus 5.5 |
| Neither model has a result on the other 3 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| AIME | Not measured | 93.3% | Only GPT-5.1 measured |
| MGSM (Vals AI) | Not measured | 93.0% | Only GPT-5.1 measured |
| AA Math Index | Not measured | 94.0 | Only GPT-5.1 measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 94.0% | Only GPT-5.1 measured |
| OTIS Mock AIME | 100.0% | 88.6% | Claude Opus 5.5 |
| FrontierMath, tiers 1 to 3 | 91.2% | Not measured | Only Claude Opus 5.5 measured |
| FrontierMath, tier 4 | 95.0% | Not measured | Only Claude Opus 5.5 measured |
| ProofBench | 100.0% | Not measured | Only Claude Opus 5.5 measured |
| LMArena Text: math | 1518 | 1446 | Claude Opus 5.5 |
| LMArena Text: mathematical work | 1516 | 1449 | Claude Opus 5.5 |
| Neither model has a result on the other 3 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index61
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 86.4% | Only GPT-5.1 measured |
| LegalBench (Vals AI) | Not measured | 85.7% | Only GPT-5.1 measured |
| CaseLaw (Vals AI) | Not measured | 73.4% | Only GPT-5.1 measured |
| CorpFin (Vals AI) | Not measured | 63.8% | Only GPT-5.1 measured |
| TaxEval (Vals AI) | Not measured | 74.9% | Only GPT-5.1 measured |
| MortgageTax (Vals AI) | Not measured | 61.4% | Only GPT-5.1 measured |
| MedQA (Vals AI) | Not measured | 96.4% | Only GPT-5.1 measured |
| MedCode (Vals AI) | 49.8% | 52.7% | GPT-5.1 |
| MMLU Pro (Artificial Analysis run) | Not measured | 87.0% | Only GPT-5.1 measured |
| SimpleQA Verified | 72.2% | 48.0% | Claude Opus 5.5 |
| LMArena Text: science | 1524 | 1459 | Claude Opus 5.5 |
| LMArena Text: medicine and healthcare | 1509 | 1456 | Claude Opus 5.5 |
| LMArena Text: legal and government | 1518 | 1459 | Claude Opus 5.5 |
| LMArena Text: business and finance | 1494 | 1431 | Claude Opus 5.5 |
| FACTS Benchmark Suite | 65.3% | 45.0% | Claude Opus 5.5 |
| Neither model has a result on the other 3 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| Design Arena: websites | 1335 | 1187 | Claude Opus 5.5 |
| Design Arena: UI components | 1385 | 1163 | Claude Opus 5.5 |
| Design Arena: game dev | 1461 | 1178 | Claude Opus 5.5 |
| Design Arena: data viz | 1397 | 1204 | Claude Opus 5.5 |
| Design Arena: 3D | 1476 | 1060 | Claude Opus 5.5 |
| Design Arena: all code categories | 1390 | 1170 | Claude Opus 5.5 |
| Design Arena: SVG | 1329 | 1149 | Claude Opus 5.5 |
| Design Arena: ASCII art | Not measured | 1119 | Only GPT-5.1 measured |
| LiveBench design | 86.9% | Not measured | Only Claude Opus 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index230
| Benchmark | Claude Opus 5.5 | GPT-5.1 | Leader |
|---|---|---|---|
| Vals Index | 70.2% | Not measured | Only Claude Opus 5.5 measured |
| LiveBench data analysis | 80.3% | Not measured | Only Claude Opus 5.5 measured |
| Public Benefits Bench (Vals AI) | 70.6% | Not measured | Only Claude Opus 5.5 measured |
| SAGE (Vals AI) | 45.8% | 43.2% | Claude Opus 5.5 |
| MedScribe (Vals AI) | 91.4% | 88.1% | Claude Opus 5.5 |
| IFBench | Not measured | 72.9% | Only GPT-5.1 measured |
| Long context reasoning (AA-LCR) | 84.7% | 80.0% | Claude Opus 5.5 |
| DTBench | 98.9% | 90.1% | Claude Opus 5.5 |
| LMCA | 68.2% | 43.9% | Claude Opus 5.5 |
| CL-bench | Not measured | 23.7% | Only GPT-5.1 measured |
| Furniture assembly | 83.3% | Not measured | Only Claude Opus 5.5 measured |
| CL-bench Life | Not measured | 17.3% | Only GPT-5.1 measured |
| LMArena Text | 1516 | 1443 | Claude Opus 5.5 |
| LMArena Text: instruction following | 1537 | 1443 | Claude Opus 5.5 |
| LMArena Text: creative writing | 1535 | 1427 | Claude Opus 5.5 |
| LMArena Vision | 1321 | 1250 | Claude Opus 5.5 |
| LMArena Text: English | 1519 | 1451 | Claude Opus 5.5 |
| LMArena Text: non-English | 1507 | 1431 | Claude Opus 5.5 |
| LMArena Text: Chinese | 1582 | 1495 | Claude Opus 5.5 |
| LMArena Text: German | Not measured | 1438 | Only GPT-5.1 measured |
| LMArena Text: Japanese | 1534 | 1453 | Claude Opus 5.5 |
| LMArena Text: Korean | Not measured | 1401 | Only GPT-5.1 measured |
| LMArena Text: French | 1493 | 1450 | Claude Opus 5.5 |
| LMArena Text: Spanish | 1508 | 1433 | Claude Opus 5.5 |
| LMArena Text: Russian | 1517 | 1435 | Claude Opus 5.5 |
| LMArena Text: Polish | Not measured | 1440 | Only GPT-5.1 measured |
| LMArena Text: multi-turn | 1501 | 1450 | Claude Opus 5.5 |
| LMArena Text: longer queries | 1532 | 1448 | Claude Opus 5.5 |
| LMArena Text: writing and language | 1532 | 1428 | Claude Opus 5.5 |
| LMArena Text: entertainment and media | 1515 | 1415 | Claude Opus 5.5 |
| LMArena Vision: English | 1317 | 1252 | Claude Opus 5.5 |
| LMArena Vision: Chinese | Not measured | 1270 | Only GPT-5.1 measured |
| LMArena Vision: reading text | 1326 | 1255 | Claude Opus 5.5 |
| LMArena Vision: humor | Not measured | 1263 | Only GPT-5.1 measured |
| LMArena Vision: captioning | Not measured | 1252 | Only GPT-5.1 measured |
| LMArena Vision: recognizing things | Not measured | 1232 | Only GPT-5.1 measured |
| LMArena Vision: creative writing | 1320 | 1266 | Claude Opus 5.5 |
| LMArena Document | Not measured | 1403 | Only GPT-5.1 measured |
| Neither model has a result on the other 8 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 5.5 | GPT-5.1 | 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
Claude Opus 5.5$0.014Fits in one request
GPT-5.1$0.0063Fits in one request
GPT-5.1 costs less
Repository review
50K input + 3K output tokens
Claude Opus 5.5$0.260Fits in one request
GPT-5.1$0.092Fits in one request
GPT-5.1 costs less
Agent loop
200K input + 10K output tokens
Claude Opus 5.5$1.00Fits in one request
GPT-5.1$0.350Fits in one request
GPT-5.1 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 | Anthropic Claude Opus 5.5 | OpenAI GPT-5.1 |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 22, 2026 | November 13, 2025 |
| Context window | 1M | 400K |
| Input $/Mtok | $4.00 | $1.25 |
| Output $/Mtok | $20.00 | $10.00 |
| Coding index | 88.8 | 40.4 |
| Independent measurements behind it | 5 | 3 |
| Cost per solved task | Not computable | $1.02 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 5.5 better than GPT-5.1 for coding?
Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 40.4 for GPT-5.1. Pick GPT-5.1 for output tokens 2.0x cheaper ($10.00 vs $20.00 per million) and work measured by MedCode (Vals AI), where it leads.
Which is cheaper, Claude Opus 5.5 or GPT-5.1?
Claude Opus 5.5 costs $4.00 per million input tokens and $20.00 per million output tokens; GPT-5.1 costs $1.25 and $10.00. Cost per solved task is known for GPT-5.1 only.
Which has the bigger context window, Claude Opus 5.5 or GPT-5.1?
Claude Opus 5.5, with 1M tokens against 400K.
How many benchmarks is the Claude Opus 5.5 vs GPT-5.1 comparison based on?
61 benchmarks have a result for both models as of October 22, 2026. Claude Opus 5.5's coding index rests on 5 independent benchmarks and GPT-5.1's on 3. Where only one model has a result, the page says so instead of naming a winner.