Claude Opus 4.6 vs Claude Opus 5.5
Updated October 21, 2026. 70 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
vs boards won of 70 shared
Decision reading
Pick Claude Opus 5.5 for coding: it scores 92.2 on the Vibe Coding Index against 66.9 for Claude Opus 4.6.
Pick Claude Opus 4.6 when what matters is LMArena Text: mathematical work or LMArena Text: business and finance, where it leads.
Model AClaude Opus 4.6Anthropic66.9/1002 independent benchmarks$1.56 per solved taskModel BClaude Opus 5.5Anthropic92.2/1002 independent benchmarksNo cost per solved task
- Shared results
- 70
- Claude Opus 4.6 only
- 38
- Claude Opus 5.5 only
- 37
- Like-for-like categories
- 8 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
Claude Opus 5.5
Claude Opus 5.5 scores 92.2 against 66.9.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Opus 5.5
Claude Opus 5.5 leads, 57.6 against 31.9.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Claude Opus 4.6 has a GPQA Diamond result, 89.7%.
Directional only
Math
AIME
No call
Only Claude Opus 4.6 has a AIME result, 95.6%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Opus 4.6 has a MMLU Pro result, 89.1%.
Directional only
Web design
Design Arena: websites
Claude Opus 5.5
Claude Opus 5.5 leads, 1335 against 1291.
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
No call
Both take 1M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Claude Opus 5.5
Claude Opus 4.6 $0.018, Claude Opus 5.5 $0.014 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Opus 4.6 has the number, $1.56.
Directional only
At a glance
- Coding index
- Claude Opus 4.6 66.9 from 2 benchmarks, Claude Opus 5.5 92.2 from 2 benchmarks.
- Widest category
- Math, 25.1 points apart on average over 6 shared benchmarks.
- Widest single gap
- FrontierMath, tier 4: Claude Opus 4.6 26.8% against Claude Opus 5.5 95.0%, 68.2 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.6 $25.00 against Claude Opus 5.5 $20.00 per million output tokens, 1.3x apart.
- Context window
- Both take 1M tokens.
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 4.6 | Bars | Claude Opus 5.5 | Ties |
|---|---|---|---|---|
| Coding | 0 | 8 | ||
| Intelligence | 0 | 2 | ||
| Agentic work | 0 | 5 | ||
| Reasoning | 0 | 12 | ||
| Math | 1 | 5 | ||
| Knowledge | 1 | 5 | ||
| Web design | 0 | 7 | ||
| General | 7 | 17 | ||
| All shared boards | 9 | 61 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index08
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| SWE-bench Verified | 75.6% | Not measured | Only Claude Opus 4.6 measured |
| SWE-bench Multilingual | 72.0% | Not measured | Only Claude Opus 4.6 measured |
| LiveBench coding | Not measured | 96.3% | Only Claude Opus 5.5 measured |
| LMArena WebDev | 1547 | 1807 | Claude Opus 5.5 |
| LiveCodeBench (Vals AI) | 84.7% | Not measured | Only Claude Opus 4.6 measured |
| SWE-bench Verified (Vals AI) | 78.2% | Not measured | Only Claude Opus 4.6 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 65.2% | Only Claude Opus 5.5 measured |
| Vibe Code Bench (Vals AI) | 57.6% | 90.3% | Claude Opus 5.5 |
| Code migration (Vals AI) | Not measured | 66.7% | Only Claude Opus 5.5 measured |
| ProgramBench (Vals AI) | Not measured | 18.5% | Only Claude Opus 5.5 measured |
| IOI (Vals AI) | Not measured | 95.1% | Only Claude Opus 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 87.6% | Only Claude Opus 5.5 measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 70.2% | Only Claude Opus 5.5 measured |
| Vibe Code Bench 1-100 (Vals AI) | Not measured | 30.4% | Only Claude Opus 5.5 measured |
| CyberBench (Vals AI) | Not measured | 74.6% | Only Claude Opus 5.5 measured |
| SciCode | Not measured | 66.9% | Only Claude Opus 5.5 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 48.5% | Not measured | Only Claude Opus 4.6 measured |
| Terminal-Bench | 79.8% | Not measured | Only Claude Opus 4.6 measured |
| FrontierCode | 26.6% | 54.6% | Claude Opus 5.5 |
| FrontierSWE | Not measured | 62.3% | Only Claude Opus 5.5 measured |
| GSO-Bench | 41.2% | Not measured | Only Claude Opus 4.6 measured |
| WeirdML | 78.0% | Not measured | Only Claude Opus 4.6 measured |
| MirrorCode | Not measured | 77.4% | Only Claude Opus 5.5 measured |
| Cybench | 93.0% | Not measured | Only Claude Opus 4.6 measured |
| ALE-Bench | Not measured | 2147.4 | Only Claude Opus 5.5 measured |
| LMArena Text: coding | 1534 | 1545 | Claude Opus 5.5 |
| LMArena Text: software and IT | 1527 | 1538 | Claude Opus 5.5 |
| LMArena WebDev: React | 1539 | 1855 | Claude Opus 5.5 |
| LMArena WebDev: HTML | 1559 | 1753 | Claude Opus 5.5 |
| LMArena WebDev: from an image | 1543 | 1753 | Claude Opus 5.5 |
| Neither model has a result on the other 8 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 31.9 | 57.6 | Claude Opus 5.5 |
| Epoch Capabilities Index | 155.7 | 168.8 | Claude Opus 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index05
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1206 | 1316 | Claude Opus 5.5 |
| Design Arena: agents building full-stack apps | 1220 | Not measured | Only Claude Opus 4.6 measured |
| Design Arena: agents building mobile apps | 1207 | 1311 | Claude Opus 5.5 |
| Design Arena: agents building Android apps | 1204 | Not measured | Only Claude Opus 4.6 measured |
| Design Arena: agents building games | 1214 | Not measured | Only Claude Opus 4.6 measured |
| Design Arena: spreadsheets | Not measured | 1359 | Only Claude Opus 5.5 measured |
| LiveBench research | Not measured | 85.0% | Only Claude Opus 5.5 measured |
| LiveBench browser | Not measured | 80.0% | Only Claude Opus 5.5 measured |
| LiveBench long agentic | Not measured | 85.0% | Only Claude Opus 5.5 measured |
| SREBench (Vals AI) | Not measured | 33.6% | Only Claude Opus 5.5 measured |
| Finance Agent (Vals AI) | Not measured | 58.6% | Only Claude Opus 5.5 measured |
| Tax Agent Bench (Vals AI) | Not measured | 45.6% | Only Claude Opus 5.5 measured |
| Legal Research Bench (Vals AI) | Not measured | 50.5% | Only Claude Opus 5.5 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 9.2% | Only Claude Opus 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 75.9% | Only Claude Opus 5.5 measured |
| BioMysteryBench (Vals AI) | Not measured | 79.3% | Only Claude Opus 5.5 measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 47.1% | Only Claude Opus 5.5 measured |
| Vals Science Index | Not measured | 58.7% | Only Claude Opus 5.5 measured |
| Time Horizon Index (Vals AI) | Not measured | 91.3% | Only Claude Opus 5.5 measured |
| CUA-bench (Vals AI) | Not measured | 14.0% | Only Claude Opus 5.5 measured |
| Robo-bench (Vals AI) | Not measured | 14.6% | Only Claude Opus 5.5 measured |
| τ²-Bench Telecom | 92.1% | Not measured | Only Claude Opus 4.6 measured |
| APEX-Agents | 46.3% | 73.5% | Claude Opus 5.5 |
| METR time horizons | 78.9% | Not measured | Only Claude Opus 4.6 measured |
| Remote Labor Index | 4.2% | 21.3% | Claude Opus 5.5 |
| DeepResearch Bench | 55.3% | Not measured | Only Claude Opus 4.6 measured |
| SpireClimb | Not measured | 3.3% | Only Claude Opus 5.5 measured |
| Vending-Bench 2 | $8,018 | $9,235 | Claude Opus 5.5 |
| LMArena Search | Not measured | 1213 | Only Claude Opus 5.5 measured |
| Neither model has a result on the other 10 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index012
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| GPQA Diamond | 89.7% | Not measured | Only Claude Opus 4.6 measured |
| LiveBench reasoning | Not measured | 92.2% | Only Claude Opus 5.5 measured |
| MysteryMechanism (Vals AI) | Not measured | 49.5% | Only Claude Opus 5.5 measured |
| MMMU Pro (Vals AI) | 83.9% | Not measured | Only Claude Opus 4.6 measured |
| GPQA Diamond (Artificial Analysis run) | 89.6% | Not measured | Only Claude Opus 4.6 measured |
| Humanity's Last Exam (Artificial Analysis run) | 39.9% | 61.4% | Claude Opus 5.5 |
| GPQA Diamond (Epoch AI run) | 90.5% | 90.6% | Claude Opus 5.5 |
| ARC-AGI | 94.0% | 98.5% | Claude Opus 5.5 |
| ARC-AGI-2 | 69.2% | 93.3% | Claude Opus 5.5 |
| SimpleBench | 67.6% | Not measured | Only Claude Opus 4.6 measured |
| Chess puzzles | 21.0% | 67.0% | Claude Opus 5.5 |
| Mystery game puzzles | 25.0% | 71.0% | Claude Opus 5.5 |
| EBR-bench | 12.7% | 71.4% | Claude Opus 5.5 |
| LMArena Text: hard prompts | 1525 | 1536 | Claude Opus 5.5 |
| LMArena Text: expert | 1544 | 1549 | Claude Opus 5.5 |
| LMArena Text: hard prompts in English | 1530 | 1535 | Claude Opus 5.5 |
| LMArena Vision: diagrams | 1340 | 1345 | Claude Opus 5.5 |
| LMArena Vision: homework | 1337 | 1362 | 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 index15
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| AIME | 95.6% | Not measured | Only Claude Opus 4.6 measured |
| OTIS Mock AIME | 94.4% | 100.0% | Claude Opus 5.5 |
| FrontierMath, tiers 1 to 3 | 66.0% | 91.2% | Claude Opus 5.5 |
| FrontierMath, tier 4 | 26.8% | 95.0% | Claude Opus 5.5 |
| ProofBench | 50.0% | 100.0% | Claude Opus 5.5 |
| LMArena Text: math | 1518 | 1518 | Claude Opus 5.5 |
| LMArena Text: mathematical work | 1525 | 1516 | Claude Opus 4.6 |
| Neither model has a result on the other 6 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index15
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| MMLU Pro | 89.1% | Not measured | Only Claude Opus 4.6 measured |
| LegalBench (Vals AI) | 85.3% | Not measured | Only Claude Opus 4.6 measured |
| CaseLaw (Vals AI) | 62.1% | Not measured | Only Claude Opus 4.6 measured |
| CorpFin (Vals AI) | 67.0% | Not measured | Only Claude Opus 4.6 measured |
| TaxEval (Vals AI) | 76.0% | Not measured | Only Claude Opus 4.6 measured |
| MortgageTax (Vals AI) | 68.5% | Not measured | Only Claude Opus 4.6 measured |
| MedQA (Vals AI) | 95.4% | Not measured | Only Claude Opus 4.6 measured |
| MedCode (Vals AI) | 49.1% | 49.8% | Claude Opus 5.5 |
| SimpleQA Verified | 47.0% | 72.2% | Claude Opus 5.5 |
| LMArena Text: science | 1519 | 1524 | Claude Opus 5.5 |
| LMArena Text: medicine and healthcare | 1504 | 1509 | Claude Opus 5.5 |
| LMArena Text: legal and government | 1512 | 1518 | Claude Opus 5.5 |
| LMArena Text: business and finance | 1497 | 1494 | Claude Opus 4.6 |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index07
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1291 | 1335 | Claude Opus 5.5 |
| Design Arena: UI components | 1284 | 1390 | Claude Opus 5.5 |
| Design Arena: game dev | 1278 | 1457 | Claude Opus 5.5 |
| Design Arena: data viz | 1279 | 1397 | Claude Opus 5.5 |
| Design Arena: 3D | 1274 | 1477 | Claude Opus 5.5 |
| Design Arena: all code categories | 1289 | 1390 | Claude Opus 5.5 |
| Design Arena: SVG | 1227 | 1332 | Claude Opus 5.5 |
| Design Arena: ASCII art | 1254 | Not measured | Only Claude Opus 4.6 measured |
| LiveBench design | Not measured | 86.9% | Only Claude Opus 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index717
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | Leader |
|---|---|---|---|
| Vals Index | Not measured | 70.2% | Only Claude Opus 5.5 measured |
| LiveBench data analysis | Not measured | 80.3% | Only Claude Opus 5.5 measured |
| Public Benefits Bench (Vals AI) | Not measured | 70.6% | Only Claude Opus 5.5 measured |
| SAGE (Vals AI) | 51.6% | 45.8% | Claude Opus 4.6 |
| MedScribe (Vals AI) | 86.7% | 91.4% | Claude Opus 5.5 |
| IFBench | 53.1% | Not measured | Only Claude Opus 4.6 measured |
| Long context reasoning (AA-LCR) | 78.0% | 84.7% | Claude Opus 5.5 |
| DTBench | 91.2% | 98.9% | Claude Opus 5.5 |
| LMCA | 55.8% | 68.2% | Claude Opus 5.5 |
| CL-bench | 20.7% | Not measured | Only Claude Opus 4.6 measured |
| Furniture assembly | 28.3% | 83.3% | Claude Opus 5.5 |
| CL-bench Life | 17.0% | Not measured | Only Claude Opus 4.6 measured |
| LMArena Text | 1501 | 1516 | Claude Opus 5.5 |
| LMArena Text: instruction following | 1521 | 1537 | Claude Opus 5.5 |
| LMArena Text: creative writing | 1505 | 1535 | Claude Opus 5.5 |
| LMArena Vision | 1316 | 1321 | Claude Opus 5.5 |
| LMArena Text: English | 1511 | 1519 | Claude Opus 5.5 |
| LMArena Text: non-English | 1488 | 1507 | Claude Opus 5.5 |
| LMArena Text: Chinese | 1551 | 1582 | Claude Opus 5.5 |
| LMArena Text: German | 1500 | Not measured | Only Claude Opus 4.6 measured |
| LMArena Text: Japanese | 1488 | 1534 | Claude Opus 5.5 |
| LMArena Text: Korean | 1464 | Not measured | Only Claude Opus 4.6 measured |
| LMArena Text: French | 1512 | 1493 | Claude Opus 4.6 |
| LMArena Text: Spanish | 1510 | 1508 | Claude Opus 4.6 |
| LMArena Text: Russian | 1497 | 1517 | Claude Opus 5.5 |
| LMArena Text: Polish | 1499 | Not measured | Only Claude Opus 4.6 measured |
| LMArena Text: multi-turn | 1511 | 1501 | Claude Opus 4.6 |
| LMArena Text: longer queries | 1518 | 1532 | Claude Opus 5.5 |
| LMArena Text: writing and language | 1502 | 1532 | Claude Opus 5.5 |
| LMArena Text: entertainment and media | 1492 | 1515 | Claude Opus 5.5 |
| LMArena Vision: English | 1324 | 1317 | Claude Opus 4.6 |
| LMArena Vision: Chinese | 1370 | Not measured | Only Claude Opus 4.6 measured |
| LMArena Vision: reading text | 1326 | 1326 | Claude Opus 4.6 |
| LMArena Vision: humor | 1314 | Not measured | Only Claude Opus 4.6 measured |
| LMArena Vision: recognizing things | 1274 | Not measured | Only Claude Opus 4.6 measured |
| LMArena Vision: creative writing | 1331 | 1320 | Claude Opus 4.6 |
| LMArena Document | 1507 | Not measured | Only Claude Opus 4.6 measured |
| Neither model has a result on the other 9 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.6 | Claude Opus 5.5 | 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 4.6$0.018Fits in one request
Claude Opus 5.5$0.014Fits in one request
Claude Opus 5.5 costs less
Repository review
50K input + 3K output tokens
Claude Opus 4.6$0.325Fits in one request
Claude Opus 5.5$0.260Fits in one request
Claude Opus 5.5 costs less
Agent loop
200K input + 10K output tokens
Claude Opus 4.6$1.25Fits in one request
Claude Opus 5.5$1.00Fits in one request
Claude Opus 5.5 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 4.6 | Anthropic Claude Opus 5.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | February 4, 2026 | September 22, 2026 |
| Context window | 1M | 1M |
| Input $/Mtok | $5.00 | $4.00 |
| Output $/Mtok | $25.00 | $20.00 |
| Coding index | 66.9 | 92.2 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | $1.56 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.6 better than Claude Opus 5.5 for coding?
Pick Claude Opus 5.5 for coding: it scores 92.2 on the Vibe Coding Index against 66.9 for Claude Opus 4.6. Pick Claude Opus 4.6 when what matters is LMArena Text: mathematical work or LMArena Text: business and finance, where it leads.
Which is cheaper, Claude Opus 4.6 or Claude Opus 5.5?
Claude Opus 4.6 costs $5.00 per million input tokens and $25.00 per million output tokens; Claude Opus 5.5 costs $4.00 and $20.00. Cost per solved task is known for Claude Opus 4.6 only.
Which has the bigger context window, Claude Opus 4.6 or Claude Opus 5.5?
Neither: both take 1M tokens.
How many benchmarks is the Claude Opus 4.6 vs Claude Opus 5.5 comparison based on?
70 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.6's coding index rests on 2 independent benchmarks and Claude Opus 5.5's on 2. Where only one model has a result, the page says so instead of naming a winner.