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Claude Opus 4.8 vs Claude Sonnet 5.5

Claude Sonnet 5.5 leads Claude Opus 4.8 on coding, 87.3 to 65.0 on the Vibe Coding Index, and Claude Sonnet 5.5 costs 2.5x less per output token ($10.00 vs $25.00 per million). Updated October 22, 2026; 83 benchmarks have a result for both.

Replace Claude Opus 4.8 Replace Claude Sonnet 5.5
Claude Opus 4.8Anthropic
Coding
65.0
Overall
69.8
Output $/M
$25.00
15
Claude Sonnet 5.5Anthropic
Coding
87.3
Overall
82.8
Output $/M
$10.00
68
vs boards won of 83 shared

Claude Opus 4.8 or Claude Sonnet 5.5: which to pick

Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 65.0 for Claude Opus 4.8, though on 5 benchmarks against 6.

Pick Claude Opus 4.8 for work measured by Design Arena: spreadsheets or LiveBench browser, where it leads.

Model AClaude Opus 4.8Anthropic65.0/1006 independent benchmarks$2.17 per solved taskModel BClaude Sonnet 5.5Anthropic87.3/1005 independent benchmarksNo cost per solved task
Shared results
83
Claude Opus 4.8 only
47
Claude Sonnet 5.5 only
13
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 4.8 65.0 from 6 benchmarks, Claude Sonnet 5.5 87.3 from 5 benchmarks.
Widest category
Web design, 16.5 points apart on average over 7 shared benchmarks.
Widest single gap
Terminal-Bench 4 (Vals AI): Claude Opus 4.8 23.2% against Claude Sonnet 5.5 64.1%, 54.5 points apart on a 0 to 100 scale.
Output price
Claude Opus 4.8 $25.00 against Claude Sonnet 5.5 $10.00 per million output tokens, 2.5x 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 4.8BarsClaude Sonnet 5.5Ties
Coding014
Intelligence02
Agentic work211
Reasoning19
Math06
Knowledge24
Web design07
General1015
All shared boards1568
CodingLike-for-likeSix of these boards feed the Vibe Coding Index014
Coding benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
LiveBench coding77.3%94.7%Claude Sonnet 5.5
LMArena WebDev15561768Claude Sonnet 5.5
AA Coding Index74.3Not measuredOnly Claude Opus 4.8 measured
LiveCodeBench (Vals AI)87.8%Not measuredOnly Claude Opus 4.8 measured
SWE-bench Verified (Vals AI)88.6%Not measuredOnly Claude Opus 4.8 measured
Terminal-Bench 4 (Vals AI)23.2%64.1%Claude Sonnet 5.5
Vibe Code Bench (Vals AI)82.7%92.4%Claude Sonnet 5.5
Code migration (Vals AI)47.3%69.8%Claude Sonnet 5.5
ProgramBench (Vals AI)1.0%6.5%Claude Sonnet 5.5
IOI (Vals AI)Not measured83.1%Only Claude Sonnet 5.5 measured
Terminal-Bench 2.1 (Vals AI)71.9%83.2%Claude Sonnet 5.5
SWE-bench Multimodal (Vals AI)Not measured58.3%Only Claude Sonnet 5.5 measured
SkillsBench (Vals AI)59.2%Not measuredOnly Claude Opus 4.8 measured
CyberBench (Vals AI)Not measured59.6%Only Claude Sonnet 5.5 measured
SciCode54.4%61.0%Claude Sonnet 5.5
Terminal-Bench Hard (Artificial Analysis run)58.3%Not measuredOnly Claude Opus 4.8 measured
FrontierCode46.5%52.1%Claude Sonnet 5.5
FrontierSWENot measured61.9%Only Claude Sonnet 5.5 measured
GSO-Bench47.1%Not measuredOnly Claude Opus 4.8 measured
WeirdML82.9%Not measuredOnly Claude Opus 4.8 measured
ALE-BenchNot measured1819.1Only Claude Sonnet 5.5 measured
LMArena Text: coding14901513Claude Sonnet 5.5
LMArena Text: software and IT14881504Claude Sonnet 5.5
LMArena WebDev: React15571817Claude Sonnet 5.5
LMArena WebDev: HTML15431741Claude Sonnet 5.5
LMArena WebDev: from an imageNot measured1737Only Claude Sonnet 5.5 measured
SciCode12.3%13.8%Claude Sonnet 5.5
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
AA Intelligence Index41.856.0Claude Sonnet 5.5
Epoch Capabilities Index159.0166.2Claude Sonnet 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index211
Agentic work benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
AA Agentic Index41.9Not measuredOnly Claude Opus 4.8 measured
Design Arena: agents building web apps12331305Claude Sonnet 5.5
Design Arena: agents building full-stack apps1249Not measuredOnly Claude Opus 4.8 measured
Design Arena: agents building mobile apps12221260Claude Sonnet 5.5
Design Arena: agents building Android apps1233Not measuredOnly Claude Opus 4.8 measured
Design Arena: agents building Godot games1231Not measuredOnly Claude Opus 4.8 measured
Design Arena: agents building games1239Not measuredOnly Claude Opus 4.8 measured
Design Arena: HTML slides1171Not measuredOnly Claude Opus 4.8 measured
Design Arena: PowerPoint slides1202Not measuredOnly Claude Opus 4.8 measured
Design Arena: spreadsheets13031260Claude Opus 4.8
LiveBench research81.8%83.6%Claude Sonnet 5.5
LiveBench browser96.0%84.0%Claude Opus 4.8
LiveBench long agentic48.3%78.8%Claude Sonnet 5.5
SREBench (Vals AI)Not measured30.1%Only Claude Sonnet 5.5 measured
Finance Agent (Vals AI)53.9%58.1%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)30.0%42.0%Claude Sonnet 5.5
Legal Research Bench (Vals AI)43.8%48.1%Claude Sonnet 5.5
Harvey's Legal Agent Benchmark (Vals AI)Not measured10.4%Only Claude Sonnet 5.5 measured
Excel Modeling Benchmark (Vals AI)69.4%75.7%Claude Sonnet 5.5
BioMysteryBench (Vals AI)Not measured81.1%Only Claude Sonnet 5.5 measured
Terminal-Bench-Science (Vals AI)4.3%47.1%Claude Sonnet 5.5
Vals Science IndexNot measured59.1%Only Claude Sonnet 5.5 measured
Time Horizon Index (Vals AI)11.8%Not measuredOnly Claude Opus 4.8 measured
τ²-Bench Telecom94.4%Not measuredOnly Claude Opus 4.8 measured
APEX-Agents48.9%75.5%Claude Sonnet 5.5
Remote Labor Index8.3%Not measuredOnly Claude Opus 4.8 measured
OSWorld 2.020.6%Not measuredOnly Claude Opus 4.8 measured
DeepResearch Bench50.2%Not measuredOnly Claude Opus 4.8 measured
PostTrainBench33.8%Not measuredOnly Claude Opus 4.8 measured
SpireClimbNot measured1.3%Only Claude Sonnet 5.5 measured
Vending-Bench 2$5,787$11,165Claude Sonnet 5.5
LMArena Search1204Not measuredOnly Claude Opus 4.8 measured
Neither model has a result on the other 9 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index19
Reasoning benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
GPQA Diamond92.4%Not measuredOnly Claude Opus 4.8 measured
LiveBench reasoning89.2%91.6%Claude Sonnet 5.5
MysteryMechanism (Vals AI)Not measured49.1%Only Claude Sonnet 5.5 measured
MMMU Pro (Vals AI)86.6%Not measuredOnly Claude Opus 4.8 measured
GPQA Diamond (Artificial Analysis run)92.0%Not measuredOnly Claude Opus 4.8 measured
Humanity's Last Exam (Artificial Analysis run)48.7%55.0%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)91.0%95.6%Claude Sonnet 5.5
ARC-AGI92.5%Not measuredOnly Claude Opus 4.8 measured
ARC-AGI-272.1%Not measuredOnly Claude Opus 4.8 measured
SimpleBench64.8%Not measuredOnly Claude Opus 4.8 measured
Chess puzzles52.0%59.0%Claude Sonnet 5.5
Mystery game puzzles36.0%65.0%Claude Sonnet 5.5
EBR-bench28.6%Not measuredOnly Claude Opus 4.8 measured
LMArena Text: hard prompts14821494Claude Sonnet 5.5
LMArena Text: expert15031531Claude Sonnet 5.5
LMArena Text: hard prompts in English14871502Claude Sonnet 5.5
LMArena Vision: diagrams13151329Claude Sonnet 5.5
LMArena Vision: homework13371331Claude Opus 4.8
Kagi LLM Benchmark88.8%Not measuredOnly Claude Opus 4.8 measured
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index06
Math benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
OTIS Mock AIME98.3%100.0%Claude Sonnet 5.5
FrontierMath, tiers 1 to 380.0%88.8%Claude Sonnet 5.5
FrontierMath, tier 456.1%80.5%Claude Sonnet 5.5
ProofBench69.0%100.0%Claude Sonnet 5.5
LMArena Text: math14861497Claude Sonnet 5.5
LMArena Text: mathematical work14971510Claude 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 index24
Knowledge benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
MMLU Pro89.6%Not measuredOnly Claude Opus 4.8 measured
LegalBench (Vals AI)83.6%Not measuredOnly Claude Opus 4.8 measured
CorpFin (Vals AI)66.7%Not measuredOnly Claude Opus 4.8 measured
TaxEval (Vals AI)75.6%Not measuredOnly Claude Opus 4.8 measured
MortgageTax (Vals AI)69.9%Not measuredOnly Claude Opus 4.8 measured
MedCode (Vals AI)53.2%52.9%Claude Opus 4.8
SimpleQA Verified53.0%46.5%Claude Opus 4.8
LMArena Text: science14771483Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641464Claude Sonnet 5.5
LMArena Text: legal and government14771483Claude Sonnet 5.5
LMArena Text: business and finance14581468Claude Sonnet 5.5
FACTS Benchmark Suite53.5%Not measuredOnly Claude Opus 4.8 measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index07
Web design benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
Design Arena: websites12581326Claude Sonnet 5.5
Design Arena: UI components12551368Claude Sonnet 5.5
Design Arena: game dev12641471Claude Sonnet 5.5
Design Arena: data viz12401392Claude Sonnet 5.5
Design Arena: 3D12221445Claude Sonnet 5.5
Design Arena: all code categories12551364Claude Sonnet 5.5
Design Arena: SVG1195Not measuredOnly Claude Opus 4.8 measured
Design Arena: ASCII art1277Not measuredOnly Claude Opus 4.8 measured
LiveBench design78.8%85.0%Claude Sonnet 5.5
GeneralLike-for-likePublic boards, shown as published, kept out of the index1015
General benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
Vals IndexNot measured70.8%Only Claude Sonnet 5.5 measured
LiveBench data analysis66.0%59.5%Claude Opus 4.8
Public Benefits Bench (Vals AI)68.1%67.2%Claude Opus 4.8
SAGE (Vals AI)54.8%51.8%Claude Opus 4.8
MedScribe (Vals AI)85.8%91.1%Claude Sonnet 5.5
Vals Multimodal Index70.9%Not measuredOnly Claude Opus 4.8 measured
IFBench62.2%Not measuredOnly Claude Opus 4.8 measured
Long context reasoning (AA-LCR)77.7%82.7%Claude Sonnet 5.5
DTBench94.9%97.3%Claude Sonnet 5.5
LMCA57.5%68.3%Claude Sonnet 5.5
Surface Evolver Bench87.5%Not measuredOnly Claude Opus 4.8 measured
Furniture assembly42.5%75.0%Claude Sonnet 5.5
LMArena Text14611473Claude Sonnet 5.5
LMArena Text: instruction following14761492Claude Sonnet 5.5
LMArena Text: creative writing14541467Claude Sonnet 5.5
LMArena Vision12941287Claude Opus 4.8
LMArena Text: English14681484Claude Sonnet 5.5
LMArena Text: non-English14501456Claude Sonnet 5.5
LMArena Text: Chinese15061535Claude Sonnet 5.5
LMArena Text: German1472Not measuredOnly Claude Opus 4.8 measured
LMArena Text: Japanese1442Not measuredOnly Claude Opus 4.8 measured
LMArena Text: Korean1431Not measuredOnly Claude Opus 4.8 measured
LMArena Text: French14811499Claude Sonnet 5.5
LMArena Text: Spanish14651451Claude Opus 4.8
LMArena Text: Russian14741454Claude Opus 4.8
LMArena Text: Polish1459Not measuredOnly Claude Opus 4.8 measured
LMArena Text: multi-turn14761465Claude Opus 4.8
LMArena Text: longer queries14831495Claude Sonnet 5.5
LMArena Text: writing and language14611474Claude Sonnet 5.5
LMArena Text: entertainment and media14401461Claude Sonnet 5.5
LMArena Vision: English12931289Claude Opus 4.8
LMArena Vision: Chinese1346Not measuredOnly Claude Opus 4.8 measured
LMArena Vision: reading text13031297Claude Opus 4.8
LMArena Vision: humor1282Not measuredOnly Claude Opus 4.8 measured
LMArena Vision: creative writing13011242Claude Opus 4.8
LMArena Document1475Not measuredOnly Claude Opus 4.8 measured
Neither model has a result on the other 10 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Opus 4.8 and Claude Sonnet 5.5
BenchmarkClaude Opus 4.8Claude Sonnet 5.5Leader
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 4.8$0.018Fits in one request
Claude Sonnet 5.5$0.0070Fits in one request

Claude Sonnet 5.5 costs less

Repository review

50K input + 3K output tokens

Claude Opus 4.8$0.325Fits in one request
Claude Sonnet 5.5$0.130Fits in one request

Claude Sonnet 5.5 costs less

Agent loop

200K input + 10K output tokens

Claude Opus 4.8$1.25Fits in one request
Claude Sonnet 5.5$0.500Fits in one request

Claude Sonnet 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.

Specifications of Claude Opus 4.8 and Claude Sonnet 5.5
SpecificationAnthropic Claude Opus 4.8Anthropic Claude Sonnet 5.5
MakerAnthropicAnthropic
WeightsNo public weights listedNo public weights listed
ReleasedMay 27, 2026September 28, 2026
Context window1M1M
Input $/Mtok$5.00$2.00
Output $/Mtok$25.00$10.00
Coding index65.087.3
Independent measurements behind it65
Cost per solved task$2.17Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 4.8 better than Claude Sonnet 5.5 for coding?

Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 65.0 for Claude Opus 4.8, though on 5 benchmarks against 6. Pick Claude Opus 4.8 for work measured by Design Arena: spreadsheets or LiveBench browser, where it leads.

Which is cheaper, Claude Opus 4.8 or Claude Sonnet 5.5?

Claude Opus 4.8 costs $5.00 per million input tokens and $25.00 per million output tokens; Claude Sonnet 5.5 costs $2.00 and $10.00. Cost per solved task is known for Claude Opus 4.8 only.

Which has the bigger context window, Claude Opus 4.8 or Claude Sonnet 5.5?

Neither: both take 1M tokens.

How many benchmarks is the Claude Opus 4.8 vs Claude Sonnet 5.5 comparison based on?

83 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.8's coding index rests on 6 independent benchmarks and Claude Sonnet 5.5's on 5. Where only one model has a result, the page says so instead of naming a winner.

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