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Claude Opus 5.5 vs Kimi K2.6

Updated October 21, 2026. 76 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Opus 5.5 Replace Kimi K2.6
Claude Opus 5.5Anthropic
Coding
92.2
Overall
57.6
Output $/M
$20.00
74
Kimi K2.6Moonshot AI
Coding
44.2
Overall
27.0
Output $/M
$3.41
2
vs boards won of 76 shared

Decision reading

Pick Claude Opus 5.5 for coding: it scores 92.2 on the Vibe Coding Index against 44.2 for Kimi K2.6.

Pick Kimi K2.6 when output tokens cost 5.9x less, or when what matters is GPQA Diamond (Epoch AI run) or SAGE (Vals AI), where it leads.

Model AClaude Opus 5.5Anthropic92.2/1002 independent benchmarksNo cost per solved taskModel BKimi K2.6Moonshot AI44.2/1001 independent benchmark$0.35 per solved task
Shared results
76
Claude Opus 5.5 only
31
Kimi K2.6 only
33
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.

At a glance

Coding index
Claude Opus 5.5 92.2 from 2 benchmarks, Kimi K2.6 44.2 from 1 benchmark.
Widest category
Math, 34.1 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: Claude Opus 5.5 100.0% against Kimi K2.6 16.0%, 84.0 points apart on a 0 to 100 scale.
Output price
Claude Opus 5.5 $20.00 against Kimi K2.6 $3.41 per million output tokens, 5.9x apart.
Context window
Claude Opus 5.5 takes 1M tokens, Kimi K2.6 262K.

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 5.5BarsKimi K2.6Ties
Coding120
Intelligence20
Agentic work80
Reasoning91
Math60
Knowledge60
Web design70
General241
All shared boards742
CodingLike-for-likeFour of these boards feed the Vibe Coding Index120
Coding benchmarks for Claude Opus 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
LiveBench coding96.3%Not measuredOnly Claude Opus 5.5 measured
LMArena WebDev18071509Claude Opus 5.5
AA Coding IndexNot measured61.8Only Kimi K2.6 measured
LiveCodeBench (Vals AI)Not measured86.8%Only Kimi K2.6 measured
SWE-bench Verified (Vals AI)Not measured76.2%Only Kimi K2.6 measured
Terminal-Bench 4 (Vals AI)65.2%Not measuredOnly Claude Opus 5.5 measured
Vibe Code Bench (Vals AI)90.3%37.9%Claude Opus 5.5
Code migration (Vals AI)66.7%27.8%Claude Opus 5.5
ProgramBench (Vals AI)18.5%0.0%Claude Opus 5.5
IOI (Vals AI)95.1%Not measuredOnly Claude Opus 5.5 measured
Terminal-Bench 2.1 (Vals AI)87.6%53.6%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%Not measuredOnly Claude Opus 5.5 measured
CyberBench (Vals AI)74.6%Not measuredOnly Claude Opus 5.5 measured
SciCode66.9%51.5%Claude Opus 5.5
Terminal-Bench Hard (Artificial Analysis run)Not measured43.9%Only Kimi K2.6 measured
FrontierCode54.6%Not measuredOnly Claude Opus 5.5 measured
FrontierSWE62.3%Not measuredOnly Claude Opus 5.5 measured
WeirdMLNot measured55.9%Only Kimi K2.6 measured
MirrorCode77.4%Not measuredOnly Claude Opus 5.5 measured
ALE-Bench2147.41092.7Claude Opus 5.5
LMArena Text: coding15451489Claude Opus 5.5
LMArena Text: software and IT15381484Claude Opus 5.5
LMArena WebDev: React18551505Claude Opus 5.5
LMArena WebDev: HTML17531485Claude Opus 5.5
LMArena WebDev: from an image17531521Claude Opus 5.5
Neither model has a result on the other 12 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Opus 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
AA Intelligence Index57.627.0Claude Opus 5.5
Epoch Capabilities Index168.8150.9Claude Opus 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index80
Agentic work benchmarks for Claude Opus 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
AA Agentic IndexNot measured20.5Only Kimi K2.6 measured
Design Arena: agents building web apps13161268Claude Opus 5.5
Design Arena: agents building full-stack appsNot measured1155Only Kimi K2.6 measured
Design Arena: agents building mobile apps13111156Claude Opus 5.5
Design Arena: agents building Android appsNot measured1166Only Kimi K2.6 measured
Design Arena: agents building Godot gamesNot measured1120Only Kimi K2.6 measured
Design Arena: agents building gamesNot measured1141Only Kimi K2.6 measured
Design Arena: HTML slidesNot measured1184Only Kimi K2.6 measured
Design Arena: PowerPoint slidesNot measured1128Only Kimi K2.6 measured
Design Arena: spreadsheets13591276Claude Opus 5.5
LiveBench research85.0%Not measuredOnly Claude Opus 5.5 measured
LiveBench browser80.0%Not measuredOnly Claude Opus 5.5 measured
LiveBench long agentic85.0%Not measuredOnly Claude Opus 5.5 measured
SREBench (Vals AI)33.6%Not measuredOnly Claude Opus 5.5 measured
Finance Agent (Vals AI)58.6%44.9%Claude Opus 5.5
Tax Agent Bench (Vals AI)45.6%12.4%Claude Opus 5.5
Legal Research Bench (Vals AI)50.5%15.9%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%57.9%Claude Opus 5.5
BioMysteryBench (Vals AI)79.3%Not measuredOnly Claude Opus 5.5 measured
Terminal-Bench-Science (Vals AI)47.1%Not measuredOnly Claude Opus 5.5 measured
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
τ²-Bench TelecomNot measured95.9%Only Kimi K2.6 measured
APEX-Agents73.5%Not measuredOnly Claude Opus 5.5 measured
Remote Labor Index21.3%Not measuredOnly Claude Opus 5.5 measured
OSWorld 2.0Not measured4.6%Only Kimi K2.6 measured
SpireClimb3.3%Not measuredOnly Claude Opus 5.5 measured
Vending-Bench 2$9,235$6,205Claude Opus 5.5
LMArena Search1213Not measuredOnly Claude Opus 5.5 measured
Neither model has a result on the other 7 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index91
Reasoning benchmarks for Claude Opus 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
GPQA DiamondNot measured89.1%Only Kimi K2.6 measured
LiveBench reasoning92.2%Not measuredOnly Claude Opus 5.5 measured
MysteryMechanism (Vals AI)49.5%Not measuredOnly Claude Opus 5.5 measured
MMMU Pro (Vals AI)Not measured86.3%Only Kimi K2.6 measured
GPQA Diamond (Artificial Analysis run)Not measured91.1%Only Kimi K2.6 measured
Humanity's Last Exam (Artificial Analysis run)61.4%37.5%Claude Opus 5.5
GPQA Diamond (Epoch AI run)90.6%90.8%Kimi K2.6
ARC-AGI98.5%Not measuredOnly Claude Opus 5.5 measured
ARC-AGI-293.3%Not measuredOnly Claude Opus 5.5 measured
Chess puzzles67.0%20.0%Claude Opus 5.5
Mystery game puzzles71.0%18.0%Claude Opus 5.5
EBR-bench71.4%2.4%Claude Opus 5.5
LMArena Text: hard prompts15361470Claude Opus 5.5
LMArena Text: expert15491491Claude Opus 5.5
LMArena Text: hard prompts in English15351471Claude Opus 5.5
LMArena Vision: diagrams13451298Claude Opus 5.5
LMArena Vision: homework13621310Claude 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 Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
OTIS Mock AIME100.0%96.1%Claude Opus 5.5
FrontierMath, tiers 1 to 391.2%57.2%Claude Opus 5.5
FrontierMath, tier 495.0%25.6%Claude Opus 5.5
ProofBench100.0%16.0%Claude Opus 5.5
LMArena Text: math15181474Claude Opus 5.5
LMArena Text: mathematical work15161480Claude 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 Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
MMLU ProNot measured87.6%Only Kimi K2.6 measured
LegalBench (Vals AI)Not measured84.7%Only Kimi K2.6 measured
CaseLaw (Vals AI)Not measured61.2%Only Kimi K2.6 measured
CorpFin (Vals AI)Not measured66.7%Only Kimi K2.6 measured
TaxEval (Vals AI)Not measured74.7%Only Kimi K2.6 measured
MortgageTax (Vals AI)Not measured65.8%Only Kimi K2.6 measured
MedCode (Vals AI)49.8%40.1%Claude Opus 5.5
SimpleQA Verified72.2%34.9%Claude Opus 5.5
LMArena Text: science15241468Claude Opus 5.5
LMArena Text: medicine and healthcare15091457Claude Opus 5.5
LMArena Text: legal and government15181462Claude Opus 5.5
LMArena Text: business and finance14941445Claude Opus 5.5
Neither model has a result on the other 5 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index70
Web design benchmarks for Claude Opus 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
Design Arena: websites13351269Claude Opus 5.5
Design Arena: UI components13901266Claude Opus 5.5
Design Arena: game dev14571251Claude Opus 5.5
Design Arena: data viz13971249Claude Opus 5.5
Design Arena: 3D14771268Claude Opus 5.5
Design Arena: all code categories13901272Claude Opus 5.5
Design Arena: SVG13321181Claude Opus 5.5
Design Arena: ASCII artNot measured1164Only Kimi K2.6 measured
LiveBench design86.9%Not measuredOnly Claude Opus 5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index241
General benchmarks for Claude Opus 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
Vals Index70.2%Not measuredOnly Claude Opus 5.5 measured
LiveBench data analysis80.3%Not measuredOnly Claude Opus 5.5 measured
Public Benefits Bench (Vals AI)70.6%56.6%Claude Opus 5.5
SAGE (Vals AI)45.8%50.2%Kimi K2.6
MedScribe (Vals AI)91.4%78.2%Claude Opus 5.5
Vals Multimodal IndexNot measured56.4%Only Kimi K2.6 measured
IFBenchNot measured76.0%Only Kimi K2.6 measured
Long context reasoning (AA-LCR)84.7%81.0%Claude Opus 5.5
DTBench98.9%90.9%Claude Opus 5.5
LMCA68.2%37.3%Claude Opus 5.5
Furniture assembly83.3%21.7%Claude Opus 5.5
ExploitBenchNot measured18.4%Only Kimi K2.6 measured
LMArena Text15161455Claude Opus 5.5
LMArena Text: instruction following15371451Claude Opus 5.5
LMArena Text: creative writing15351434Claude Opus 5.5
LMArena Vision13211282Claude Opus 5.5
LMArena Text: English15191460Claude Opus 5.5
LMArena Text: non-English15071446Claude Opus 5.5
LMArena Text: Chinese15821520Claude Opus 5.5
LMArena Text: GermanNot measured1451Only Kimi K2.6 measured
LMArena Text: Japanese15341443Claude Opus 5.5
LMArena Text: KoreanNot measured1427Only Kimi K2.6 measured
LMArena Text: French14931471Claude Opus 5.5
LMArena Text: Spanish15081464Claude Opus 5.5
LMArena Text: Russian15171446Claude Opus 5.5
LMArena Text: PolishNot measured1438Only Kimi K2.6 measured
LMArena Text: multi-turn15011453Claude Opus 5.5
LMArena Text: longer queries15321468Claude Opus 5.5
LMArena Text: writing and language15321439Claude Opus 5.5
LMArena Text: entertainment and media15151428Claude Opus 5.5
LMArena Vision: English13171287Claude Opus 5.5
LMArena Vision: ChineseNot measured1346Only Kimi K2.6 measured
LMArena Vision: reading text13261291Claude Opus 5.5
LMArena Vision: humorNot measured1280Only Kimi K2.6 measured
LMArena Vision: creative writing13201273Claude Opus 5.5
LMArena DocumentNot measured1451Only Kimi K2.6 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 5.5 and Kimi K2.6
BenchmarkClaude Opus 5.5Kimi K2.6Leader
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
Kimi K2.6$0.0024Fits in one request

Kimi K2.6 costs less

Repository review

50K input + 3K output tokens

Claude Opus 5.5$0.260Fits in one request
Kimi K2.6$0.043Fits in one request

Kimi K2.6 costs less

Agent loop

200K input + 10K output tokens

Claude Opus 5.5$1.00Fits in one request
Kimi K2.6$0.164Fits in one request

Kimi K2.6 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 Kimi K2.6
SpecificationAnthropic Claude Opus 5.5MoonshotAI Kimi K2.6
MakerAnthropicMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedSeptember 22, 2026April 20, 2026
Context window1M262K
Input $/Mtok$4.00$0.65
Output $/Mtok$20.00$3.41
Coding index92.244.2
Independent measurements behind it21
Cost per solved taskNot computable$0.35
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 5.5 better than Kimi K2.6 for coding?

Pick Claude Opus 5.5 for coding: it scores 92.2 on the Vibe Coding Index against 44.2 for Kimi K2.6. Pick Kimi K2.6 when output tokens cost 5.9x less, or when what matters is GPQA Diamond (Epoch AI run) or SAGE (Vals AI), where it leads.

Which is cheaper, Claude Opus 5.5 or Kimi K2.6?

Claude Opus 5.5 costs $4.00 per million input tokens and $20.00 per million output tokens; Kimi K2.6 costs $0.65 and $3.41. Cost per solved task is known for Kimi K2.6 only.

Which has the bigger context window, Claude Opus 5.5 or Kimi K2.6?

Claude Opus 5.5, with 1M tokens against 262K.

How many benchmarks is the Claude Opus 5.5 vs Kimi K2.6 comparison based on?

76 benchmarks have a result for both models as of October 21, 2026. Claude Opus 5.5's coding index rests on 2 independent benchmarks and Kimi K2.6's on 1. Where only one model has a result, the page says so instead of naming a winner.

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