Claude Opus 5.5 vs Claude Sonnet 4.5
Claude Opus 5.5 leads Claude Sonnet 4.5 on coding, 88.8 to 39.5 on the Vibe Coding Index, and Claude Sonnet 4.5 costs 1.3x less per output token ($15.00 vs $20.00 per million). Updated October 22, 2026; 59 benchmarks have a result for both.
vs boards won of 59 shared
Claude Opus 5.5 or Claude Sonnet 4.5: which to pick
Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5.
Pick Claude Sonnet 4.5 for output tokens 1.3x cheaper ($15.00 vs $20.00 per million).
Model AClaude Opus 5.5Anthropic88.8/1005 independent benchmarksNo cost per solved taskModel BClaude Sonnet 4.5Anthropic39.5/1003 independent benchmarks$1.16 per solved task
- Shared results
- 59
- Claude Opus 5.5 only
- 50
- Claude Sonnet 4.5 only
- 36
- 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 39.5.
5 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Opus 5.5
Claude Opus 5.5 leads, 57.6 against 20.7.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Claude Sonnet 4.5 has a AA Agentic Index result, 15.8.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Sonnet 4.5 has a GPQA Diamond result, 81.6%.
Directional only
Math
AIME
No call
Only Claude Sonnet 4.5 has a AIME result, 88.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Sonnet 4.5 has a MMLU Pro result, 87.4%.
Directional only
Web design
Design Arena: websites
Claude Opus 5.5
Claude Opus 5.5 leads, 1335 against 1189.
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 Sonnet 4.5
Claude Opus 5.5 $0.014, Claude Sonnet 4.5 $0.011 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Sonnet 4.5 has the number, $1.16.
Directional only
At a glance
- Coding index
- Claude Opus 5.5 88.8 from 5 benchmarks, Claude Sonnet 4.5 39.5 from 3 benchmarks.
- Widest category
- Math, 47.3 points apart on average over 6 shared benchmarks.
- Widest single gap
- FrontierMath, tier 4: Claude Opus 5.5 95.0% against Claude Sonnet 4.5 2.4%, 92.6 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 5.5 $20.00 against Claude Sonnet 4.5 $15.00 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 5.5 | Bars | Claude Sonnet 4.5 | Ties |
|---|---|---|---|---|
| Coding | 6 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 4 | 0 | ||
| Reasoning | 9 | 0 | ||
| Math | 6 | 0 | ||
| Knowledge | 7 | 0 | ||
| Web design | 7 | 0 | ||
| General | 18 | 0 | ||
| All shared boards | 59 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index60
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 74.8% | Only Claude Sonnet 4.5 measured |
| SWE-bench Multilingual | Not measured | 67.0% | Only Claude Sonnet 4.5 measured |
| LiveBench coding | 96.3% | Not measured | Only Claude Opus 5.5 measured |
| LMArena WebDev | 1807 | 1394 | Claude Opus 5.5 |
| AA Coding Index | Not measured | 52.1 | Only Claude Sonnet 4.5 measured |
| LiveCodeBench (Vals AI) | Not measured | 73.0% | Only Claude Sonnet 4.5 measured |
| SWE-bench Verified (Vals AI) | Not measured | 70.0% | Only Claude Sonnet 4.5 measured |
| Terminal-Bench 4 (Vals AI) | 65.2% | Not measured | Only Claude Opus 5.5 measured |
| Vibe Code Bench (Vals AI) | 90.3% | 22.6% | 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 |
| SciCode | 66.9% | Not measured | Only Claude Opus 5.5 measured |
| Terminal-Bench | Not measured | 46.5% | Only Claude Sonnet 4.5 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 | 14.7% | Only Claude Sonnet 4.5 measured |
| WeirdML | Not measured | 47.7% | Only Claude Sonnet 4.5 measured |
| MirrorCode | 77.4% | Not measured | Only Claude Opus 5.5 measured |
| Cybench | Not measured | 60.0% | Only Claude Sonnet 4.5 measured |
| ALE-Bench | 2147.4 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Text: coding | 1545 | 1488 | Claude Opus 5.5 |
| LMArena Text: software and IT | 1538 | 1473 | Claude Opus 5.5 |
| LMArena WebDev: React | 1855 | 1386 | Claude Opus 5.5 |
| LMArena WebDev: HTML | 1753 | 1399 | Claude Opus 5.5 |
| LMArena WebDev: from an image | 1753 | Not measured | Only Claude Opus 5.5 measured |
| 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 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 57.6 | 20.7 | Claude Opus 5.5 |
| Epoch Capabilities Index | 168.8 | 146.7 | Claude Opus 5.5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 15.8 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building web apps | 1316 | 1060 | Claude Opus 5.5 |
| Design Arena: agents building full-stack apps | Not measured | 1050 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building mobile apps | 1308 | 1137 | Claude Opus 5.5 |
| 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 |
| APEX-Agents | 73.5% | Not measured | Only Claude Opus 5.5 measured |
| METR time horizons | Not measured | 67.4% | Only Claude Sonnet 4.5 measured |
| Remote Labor Index | 21.3% | 2.1% | Claude Opus 5.5 |
| GDPval | Not measured | 42.5% | Only Claude Sonnet 4.5 measured |
| DeepResearch Bench | Not measured | 52.6% | Only Claude Sonnet 4.5 measured |
| OSWorld | Not measured | 62.9% | Only Claude Sonnet 4.5 measured |
| SpireClimb | 3.3% | Not measured | Only Claude Opus 5.5 measured |
| Vending-Bench 2 | $9,235 | $3,839 | Claude Opus 5.5 |
| LMArena Search | 1213 | Not measured | Only Claude Opus 5.5 measured |
| Berkeley Function Calling Leaderboard (BFCL) | Not measured | 73.2% | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 11 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 81.6% | Only Claude Sonnet 4.5 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 | 79.3% | Only Claude Sonnet 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 61.4% | Not measured | Only Claude Opus 5.5 measured |
| GPQA Diamond (Epoch AI run) | 90.6% | 82.3% | Claude Opus 5.5 |
| ARC-AGI | 98.5% | 63.7% | Claude Opus 5.5 |
| ARC-AGI-2 | 93.3% | 13.6% | Claude Opus 5.5 |
| SimpleBench | Not measured | 54.3% | Only Claude Sonnet 4.5 measured |
| Chess puzzles | 67.0% | 10.0% | Claude Opus 5.5 |
| Mystery game puzzles | 71.0% | 17.0% | Claude Opus 5.5 |
| EBR-bench | 71.4% | 2.4% | Claude Opus 5.5 |
| VPCT | Not measured | 39.8% | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts | 1536 | 1462 | Claude Opus 5.5 |
| LMArena Text: expert | 1549 | 1483 | Claude Opus 5.5 |
| LMArena Text: hard prompts in English | 1535 | 1471 | Claude Opus 5.5 |
| LMArena Vision: diagrams | 1345 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Vision: homework | 1362 | Not measured | Only Claude Opus 5.5 measured |
| Kagi LLM Benchmark | Not measured | 57.9% | Only Claude Sonnet 4.5 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 | Claude Opus 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AIME | Not measured | 88.2% | Only Claude Sonnet 4.5 measured |
| MGSM (Vals AI) | Not measured | 94.3% | Only Claude Sonnet 4.5 measured |
| OTIS Mock AIME | 100.0% | 77.8% | Claude Opus 5.5 |
| FrontierMath, tiers 1 to 3 | 91.2% | 23.9% | Claude Opus 5.5 |
| FrontierMath, tier 4 | 95.0% | 2.4% | Claude Opus 5.5 |
| ProofBench | 100.0% | 19.0% | Claude Opus 5.5 |
| MATH level 5 | Not measured | 97.7% | Only Claude Sonnet 4.5 measured |
| LMArena Text: math | 1518 | 1449 | Claude Opus 5.5 |
| LMArena Text: mathematical work | 1516 | 1462 | Claude Opus 5.5 |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 87.4% | Only Claude Sonnet 4.5 measured |
| LegalBench (Vals AI) | Not measured | 84.1% | Only Claude Sonnet 4.5 measured |
| CaseLaw (Vals AI) | Not measured | 62.2% | Only Claude Sonnet 4.5 measured |
| CorpFin (Vals AI) | Not measured | 62.0% | Only Claude Sonnet 4.5 measured |
| TaxEval (Vals AI) | Not measured | 73.3% | Only Claude Sonnet 4.5 measured |
| MortgageTax (Vals AI) | Not measured | 64.0% | Only Claude Sonnet 4.5 measured |
| MedQA (Vals AI) | Not measured | 94.7% | Only Claude Sonnet 4.5 measured |
| MedCode (Vals AI) | 49.8% | 44.1% | Claude Opus 5.5 |
| SimpleQA Verified | 72.2% | 30.7% | Claude Opus 5.5 |
| LMArena Text: science | 1524 | 1448 | Claude Opus 5.5 |
| LMArena Text: medicine and healthcare | 1509 | 1444 | Claude Opus 5.5 |
| LMArena Text: legal and government | 1518 | 1451 | Claude Opus 5.5 |
| LMArena Text: business and finance | 1494 | 1440 | Claude Opus 5.5 |
| FACTS Benchmark Suite | 65.3% | 40.6% | Claude Opus 5.5 |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1335 | 1189 | Claude Opus 5.5 |
| Design Arena: UI components | 1385 | 1170 | Claude Opus 5.5 |
| Design Arena: game dev | 1461 | 1166 | Claude Opus 5.5 |
| Design Arena: data viz | 1397 | 1167 | Claude Opus 5.5 |
| Design Arena: 3D | 1476 | 1157 | Claude Opus 5.5 |
| Design Arena: all code categories | 1390 | 1182 | Claude Opus 5.5 |
| Design Arena: SVG | 1329 | 1115 | Claude Opus 5.5 |
| Design Arena: ASCII art | Not measured | 1205 | Only Claude Sonnet 4.5 measured |
| LiveBench design | 86.9% | Not measured | Only Claude Opus 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index180
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | 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% | 36.1% | Claude Opus 5.5 |
| MedScribe (Vals AI) | 91.4% | 84.5% | Claude Opus 5.5 |
| Long context reasoning (AA-LCR) | 84.7% | Not measured | Only Claude Opus 5.5 measured |
| DTBench | 98.9% | 83.2% | Claude Opus 5.5 |
| LMCA | 68.2% | 38.8% | Claude Opus 5.5 |
| Furniture assembly | 83.3% | Not measured | Only Claude Opus 5.5 measured |
| LMArena Text | 1516 | 1438 | Claude Opus 5.5 |
| LMArena Text: instruction following | 1537 | 1459 | Claude Opus 5.5 |
| LMArena Text: creative writing | 1535 | 1442 | Claude Opus 5.5 |
| LMArena Vision | 1321 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Text: English | 1519 | 1450 | Claude Opus 5.5 |
| LMArena Text: non-English | 1507 | 1425 | Claude Opus 5.5 |
| LMArena Text: Chinese | 1582 | 1460 | Claude Opus 5.5 |
| LMArena Text: German | Not measured | 1427 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Japanese | 1534 | 1390 | Claude Opus 5.5 |
| LMArena Text: Korean | Not measured | 1402 | Only Claude Sonnet 4.5 measured |
| LMArena Text: French | 1493 | 1459 | Claude Opus 5.5 |
| LMArena Text: Spanish | 1508 | 1458 | Claude Opus 5.5 |
| LMArena Text: Russian | 1517 | 1437 | Claude Opus 5.5 |
| LMArena Text: Polish | Not measured | 1423 | Only Claude Sonnet 4.5 measured |
| LMArena Text: multi-turn | 1501 | 1465 | Claude Opus 5.5 |
| LMArena Text: longer queries | 1532 | 1475 | Claude Opus 5.5 |
| LMArena Text: writing and language | 1532 | 1442 | Claude Opus 5.5 |
| LMArena Text: entertainment and media | 1515 | 1428 | Claude Opus 5.5 |
| LMArena Vision: English | 1317 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Vision: reading text | 1326 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Vision: creative writing | 1320 | Not measured | Only Claude Opus 5.5 measured |
| LMArena Document | Not measured | 1450 | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 5.5 | Claude Sonnet 4.5 | 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 5.5$0.014Fits in one request
Claude Sonnet 4.5$0.011Fits in one request
Claude Sonnet 4.5 costs less
Repository review
50K input + 3K output tokens
Claude Opus 5.5$0.260Fits in one request
Claude Sonnet 4.5$0.195Fits in one request
Claude Sonnet 4.5 costs less
Agent loop
200K input + 10K output tokens
Claude Opus 5.5$1.00Fits in one request
Claude Sonnet 4.5$0.750Fits in one request
Claude Sonnet 4.5 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 5.5 | Anthropic Claude Sonnet 4.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | September 22, 2026 | September 29, 2025 |
| Context window | 1M | 1M |
| Input $/Mtok | $4.00 | $3.00 |
| Output $/Mtok | $20.00 | $15.00 |
| Coding index | 88.8 | 39.5 |
| Independent measurements behind it | 5 | 3 |
| Cost per solved task | Not computable | $1.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 5.5 better than Claude Sonnet 4.5 for coding?
Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for output tokens 1.3x cheaper ($15.00 vs $20.00 per million).
Which is cheaper, Claude Opus 5.5 or Claude Sonnet 4.5?
Claude Opus 5.5 costs $4.00 per million input tokens and $20.00 per million output tokens; Claude Sonnet 4.5 costs $3.00 and $15.00. Cost per solved task is known for Claude Sonnet 4.5 only.
Which has the bigger context window, Claude Opus 5.5 or Claude Sonnet 4.5?
Neither: both take 1M tokens.
How many benchmarks is the Claude Opus 5.5 vs Claude Sonnet 4.5 comparison based on?
59 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 Claude Sonnet 4.5's on 3. Where only one model has a result, the page says so instead of naming a winner.