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Claude Opus 5.5 vs Claude Sonnet 5

Claude Opus 5.5 leads Claude Sonnet 5 on coding, 88.8 to 57.7 on the Vibe Coding Index, and Claude Sonnet 5 costs 2.0x less per output token ($10.00 vs $20.00 per million). Updated October 22, 2026; 90 benchmarks have a result for both.

Replace Claude Opus 5.5 Replace Claude Sonnet 5
Claude Opus 5.5Anthropic
Coding
88.8
Overall
87.1
Output $/M
$20.00
89
Claude Sonnet 5Anthropic
Coding
57.7
Overall
63.2
Output $/M
$10.00
1
vs boards won of 90 shared

Claude Opus 5.5 or Claude Sonnet 5: which to pick

Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 57.7 for Claude Sonnet 5, though on 5 benchmarks against 6.

Pick Claude Sonnet 5 for output tokens 2.0x cheaper ($10.00 vs $20.00 per million) and work measured by SAGE (Vals AI), where it leads.

Model AClaude Opus 5.5Anthropic88.8/1005 independent benchmarksNo cost per solved taskModel BClaude Sonnet 5Anthropic57.7/1006 independent benchmarks$1.87 per solved task
Shared results
90
Claude Opus 5.5 only
19
Claude Sonnet 5 only
31
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.

At a glance

Coding index
Claude Opus 5.5 88.8 from 5 benchmarks, Claude Sonnet 5 57.7 from 6 benchmarks.
Widest category
Math, 22.3 points apart on average over 6 shared benchmarks.
Widest single gap
Terminal-Bench 4 (Vals AI): Claude Opus 5.5 65.2% against Claude Sonnet 5 10.6%, 72.7 points apart on a 0 to 100 scale.
Output price
Claude Opus 5.5 $20.00 against Claude Sonnet 5 $10.00 per million output tokens, 2.0x 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.

Boards won, where both have a result
CategoryClaude Opus 5.5BarsClaude Sonnet 5Ties
Coding190
Intelligence20
Agentic work140
Reasoning100
Math60
Knowledge60
Web design80
General241
All shared boards891
CodingLike-for-likeSix of these boards feed the Vibe Coding Index190
Coding benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
LiveBench coding96.3%74.7%Claude Opus 5.5
LMArena WebDev18071540Claude Opus 5.5
AA Coding IndexNot measured71.5Only Claude Sonnet 5 measured
LiveCodeBench (Vals AI)Not measured82.4%Only Claude Sonnet 5 measured
SWE-bench Verified (Vals AI)Not measured79.6%Only Claude Sonnet 5 measured
Terminal-Bench 4 (Vals AI)65.2%10.6%Claude Opus 5.5
Vibe Code Bench (Vals AI)90.3%81.3%Claude Opus 5.5
Code migration (Vals AI)66.7%44.4%Claude Opus 5.5
ProgramBench (Vals AI)18.5%0.0%Claude Opus 5.5
IOI (Vals AI)95.1%45.0%Claude Opus 5.5
Terminal-Bench 2.1 (Vals AI)87.6%74.5%Claude Opus 5.5
SWE-bench Multimodal (Vals AI)70.2%Not measuredOnly Claude Opus 5.5 measured
Vibe Code Bench 1-100 (Vals AI)30.4%13.8%Claude Opus 5.5
SkillsBench (Vals AI)Not measured46.5%Only Claude Sonnet 5 measured
CyberBench (Vals AI)74.6%70.3%Claude Opus 5.5
SciCode66.9%54.3%Claude Opus 5.5
FrontierCode54.6%42.7%Claude Opus 5.5
FrontierSWE62.3%Not measuredOnly Claude Opus 5.5 measured
GSO-BenchNot measured37.3%Only Claude Sonnet 5 measured
WeirdMLNot measured68.8%Only Claude Sonnet 5 measured
MirrorCode77.4%Not measuredOnly Claude Opus 5.5 measured
ALE-Bench2147.41463.1Claude Opus 5.5
LMArena Text: coding15451483Claude Opus 5.5
LMArena Text: software and IT15381474Claude Opus 5.5
LMArena WebDev: React18551541Claude Opus 5.5
LMArena WebDev: HTML17531527Claude Opus 5.5
LMArena WebDev: from an image17531540Claude Opus 5.5
SciCode18.5%10.7%Claude Opus 5.5
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
AA Intelligence Index57.638.2Claude Opus 5.5
Epoch Capabilities Index168.8156.9Claude Opus 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index140
Agentic work benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
AA Agentic IndexNot measured43.6Only Claude Sonnet 5 measured
Design Arena: agents building web apps13161245Claude Opus 5.5
Design Arena: agents building full-stack appsNot measured1249Only Claude Sonnet 5 measured
Design Arena: agents building mobile apps13081215Claude Opus 5.5
Design Arena: agents building Android appsNot measured1227Only Claude Sonnet 5 measured
Design Arena: agents building Godot gamesNot measured1225Only Claude Sonnet 5 measured
Design Arena: agents building gamesNot measured1227Only Claude Sonnet 5 measured
Design Arena: HTML slidesNot measured1168Only Claude Sonnet 5 measured
Design Arena: PowerPoint slidesNot measured1191Only Claude Sonnet 5 measured
Design Arena: spreadsheets13681035Claude Opus 5.5
LiveBench research85.0%82.8%Claude Opus 5.5
LiveBench browser80.0%72.0%Claude Opus 5.5
LiveBench long agentic85.0%39.0%Claude Opus 5.5
SREBench (Vals AI)33.6%0.4%Claude Opus 5.5
Finance Agent (Vals AI)58.6%53.9%Claude Opus 5.5
Tax Agent Bench (Vals AI)45.6%29.4%Claude Opus 5.5
Legal Research Bench (Vals AI)50.5%41.8%Claude Opus 5.5
Harvey's Legal Agent Benchmark (Vals AI)9.2%Not measuredOnly Claude Opus 5.5 measured
Excel Modeling Benchmark (Vals AI)75.9%66.3%Claude Opus 5.5
BioMysteryBench (Vals AI)79.3%Not measuredOnly Claude Opus 5.5 measured
Terminal-Bench-Science (Vals AI)47.1%5.7%Claude Opus 5.5
Vals Science Index58.7%Not measuredOnly Claude Opus 5.5 measured
Time Horizon Index (Vals AI)91.3%Not measuredOnly Claude Opus 5.5 measured
CUA-bench (Vals AI)14.0%Not measuredOnly Claude Opus 5.5 measured
Robo-bench (Vals AI)14.6%Not measuredOnly Claude Opus 5.5 measured
APEX-Agents73.5%54.5%Claude Opus 5.5
Remote Labor Index21.3%Not measuredOnly Claude Opus 5.5 measured
SpireClimb3.3%Not measuredOnly Claude Opus 5.5 measured
Vending-Bench 2$9,235$6,378Claude Opus 5.5
LMArena Search1213Not measuredOnly Claude Opus 5.5 measured
Neither model has a result on the other 11 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index100
Reasoning benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
GPQA DiamondNot measured88.9%Only Claude Sonnet 5 measured
LiveBench reasoning92.2%88.7%Claude Opus 5.5
MysteryMechanism (Vals AI)49.5%Not measuredOnly Claude Opus 5.5 measured
MMMU Pro (Vals AI)Not measured83.0%Only Claude Sonnet 5 measured
GPQA Diamond (Artificial Analysis run)Not measured91.1%Only Claude Sonnet 5 measured
Humanity's Last Exam (Artificial Analysis run)61.4%41.3%Claude Opus 5.5
GPQA Diamond (Epoch AI run)90.6%90.5%Claude Opus 5.5
ARC-AGI98.5%Not measuredOnly Claude Opus 5.5 measured
ARC-AGI-293.3%Not measuredOnly Claude Opus 5.5 measured
SimpleBenchNot measured60.6%Only Claude Sonnet 5 measured
Chess puzzles67.0%45.0%Claude Opus 5.5
Mystery game puzzles71.0%35.0%Claude Opus 5.5
EBR-bench71.4%Not measuredOnly Claude Opus 5.5 measured
LMArena Text: hard prompts15361461Claude Opus 5.5
LMArena Text: expert15491489Claude Opus 5.5
LMArena Text: hard prompts in English15351464Claude Opus 5.5
LMArena Vision: diagrams13451293Claude Opus 5.5
LMArena Vision: homework13621311Claude Opus 5.5
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
OTIS Mock AIME100.0%94.7%Claude Opus 5.5
FrontierMath, tiers 1 to 391.2%65.6%Claude Opus 5.5
FrontierMath, tier 495.0%29.3%Claude Opus 5.5
ProofBench100.0%77.0%Claude Opus 5.5
LMArena Text: math15181467Claude Opus 5.5
LMArena Text: mathematical work15161481Claude Opus 5.5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index60
Knowledge benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
MMLU ProNot measured87.5%Only Claude Sonnet 5 measured
LegalBench (Vals AI)Not measured83.9%Only Claude Sonnet 5 measured
CorpFin (Vals AI)Not measured67.0%Only Claude Sonnet 5 measured
TaxEval (Vals AI)Not measured75.6%Only Claude Sonnet 5 measured
MortgageTax (Vals AI)Not measured70.0%Only Claude Sonnet 5 measured
MedCode (Vals AI)49.8%47.5%Claude Opus 5.5
SimpleQA Verified72.2%33.7%Claude Opus 5.5
LMArena Text: science15241460Claude Opus 5.5
LMArena Text: medicine and healthcare15091442Claude Opus 5.5
LMArena Text: legal and government15181454Claude Opus 5.5
LMArena Text: business and finance14941436Claude Opus 5.5
FACTS Benchmark Suite65.3%Not measuredOnly Claude Opus 5.5 measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index80
Web design benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
Design Arena: websites13351274Claude Opus 5.5
Design Arena: UI components13851277Claude Opus 5.5
Design Arena: game dev14611277Claude Opus 5.5
Design Arena: data viz13971251Claude Opus 5.5
Design Arena: 3D14761261Claude Opus 5.5
Design Arena: all code categories13901275Claude Opus 5.5
Design Arena: SVG13291192Claude Opus 5.5
Design Arena: ASCII artNot measured1207Only Claude Sonnet 5 measured
LiveBench design86.9%82.0%Claude Opus 5.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index241
General benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
Vals Index70.2%Not measuredOnly Claude Opus 5.5 measured
LiveBench data analysis80.3%71.7%Claude Opus 5.5
Public Benefits Bench (Vals AI)70.6%66.0%Claude Opus 5.5
SAGE (Vals AI)45.8%48.9%Claude Sonnet 5
MedScribe (Vals AI)91.4%76.0%Claude Opus 5.5
Vals Multimodal IndexNot measured68.8%Only Claude Sonnet 5 measured
Long context reasoning (AA-LCR)84.7%82.0%Claude Opus 5.5
DTBench98.9%92.5%Claude Opus 5.5
LMCA68.2%50.0%Claude Opus 5.5
Surface Evolver BenchNot measured60.0%Only Claude Sonnet 5 measured
Furniture assembly83.3%Not measuredOnly Claude Opus 5.5 measured
LMArena Text15161442Claude Opus 5.5
LMArena Text: instruction following15371452Claude Opus 5.5
LMArena Text: creative writing15351416Claude Opus 5.5
LMArena Vision13211273Claude Opus 5.5
LMArena Text: English15191450Claude Opus 5.5
LMArena Text: non-English15071431Claude Opus 5.5
LMArena Text: Chinese15821478Claude Opus 5.5
LMArena Text: GermanNot measured1442Only Claude Sonnet 5 measured
LMArena Text: Japanese15341422Claude Opus 5.5
LMArena Text: KoreanNot measured1412Only Claude Sonnet 5 measured
LMArena Text: French14931463Claude Opus 5.5
LMArena Text: Spanish15081438Claude Opus 5.5
LMArena Text: Russian15171450Claude Opus 5.5
LMArena Text: PolishNot measured1425Only Claude Sonnet 5 measured
LMArena Text: multi-turn15011453Claude Opus 5.5
LMArena Text: longer queries15321462Claude Opus 5.5
LMArena Text: writing and language15321436Claude Opus 5.5
LMArena Text: entertainment and media15151411Claude Opus 5.5
LMArena Vision: English13171275Claude Opus 5.5
LMArena Vision: ChineseNot measured1331Only Claude Sonnet 5 measured
LMArena Vision: reading text13261288Claude Opus 5.5
LMArena Vision: humorNot measured1261Only Claude Sonnet 5 measured
LMArena Vision: creative writing13201246Claude Opus 5.5
LMArena DocumentNot measured1466Only Claude Sonnet 5 measured
Neither model has a result on the other 11 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Opus 5.5 and Claude Sonnet 5
BenchmarkClaude Opus 5.5Claude Sonnet 5Leader
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 5$0.0070Fits in one request

Claude Sonnet 5 costs less

Repository review

50K input + 3K output tokens

Claude Opus 5.5$0.260Fits in one request
Claude Sonnet 5$0.130Fits in one request

Claude Sonnet 5 costs less

Agent loop

200K input + 10K output tokens

Claude Opus 5.5$1.00Fits in one request
Claude Sonnet 5$0.500Fits in one request

Claude Sonnet 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.

Specifications of Claude Opus 5.5 and Claude Sonnet 5
SpecificationAnthropic Claude Opus 5.5Anthropic Claude Sonnet 5
MakerAnthropicAnthropic
WeightsNo public weights listedNo public weights listed
ReleasedSeptember 22, 2026June 30, 2026
Context window1M1M
Input $/Mtok$4.00$2.00
Output $/Mtok$20.00$10.00
Coding index88.857.7
Independent measurements behind it56
Cost per solved taskNot computable$1.87
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 5.5 better than Claude Sonnet 5 for coding?

Pick Claude Opus 5.5 for coding: it scores 88.8 on the Vibe Coding Index against 57.7 for Claude Sonnet 5, though on 5 benchmarks against 6. Pick Claude Sonnet 5 for output tokens 2.0x cheaper ($10.00 vs $20.00 per million) and work measured by SAGE (Vals AI), where it leads.

Which is cheaper, Claude Opus 5.5 or Claude Sonnet 5?

Claude Opus 5.5 costs $4.00 per million input tokens and $20.00 per million output tokens; Claude Sonnet 5 costs $2.00 and $10.00. Cost per solved task is known for Claude Sonnet 5 only.

Which has the bigger context window, Claude Opus 5.5 or Claude Sonnet 5?

Neither: both take 1M tokens.

How many benchmarks is the Claude Opus 5.5 vs Claude Sonnet 5 comparison based on?

90 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 5's on 6. Where only one model has a result, the page says so instead of naming a winner.

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