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Claude Sonnet 5.5 vs Kimi K2.6

Updated October 21, 2026. 73 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Sonnet 5.5 Replace Kimi K2.6
Claude Sonnet 5.5Anthropic
Coding
88.9
Overall
56.0
Output $/M
$10.00
70
Kimi K2.6Moonshot AI
Coding
44.2
Overall
27.0
Output $/M
$3.41
3
vs boards won of 73 shared

Decision reading

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 44.2 for Kimi K2.6.

Pick Kimi K2.6 when output tokens cost 2.9x less, or when what matters is Design Arena: spreadsheets or LMArena Text: Spanish, where it leads.

Model AClaude Sonnet 5.5Anthropic88.9/1002 independent benchmarksNo cost per solved taskModel BKimi K2.6Moonshot AI44.2/1001 independent benchmark$0.35 per solved task
Shared results
73
Claude Sonnet 5.5 only
22
Kimi K2.6 only
36
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 Sonnet 5.5 88.9 from 2 benchmarks, Kimi K2.6 44.2 from 1 benchmark.
Widest category
Math, 30.5 points apart on average over 6 shared benchmarks.
Widest single gap
ProofBench: Claude Sonnet 5.5 100.0% against Kimi K2.6 16.0%, 84.0 points apart on a 0 to 100 scale.
Output price
Claude Sonnet 5.5 $10.00 against Kimi K2.6 $3.41 per million output tokens, 2.9x apart.
Context window
Claude Sonnet 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 Sonnet 5.5BarsKimi K2.6Ties
Coding120
Intelligence20
Agentic work71
Reasoning90
Math60
Knowledge60
Web design60
General222
All shared boards703
CodingLike-for-likeFour of these boards feed the Vibe Coding Index120
Coding benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
LiveBench coding94.7%Not measuredOnly Claude Sonnet 5.5 measured
LMArena WebDev17681509Claude Sonnet 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)64.1%Not measuredOnly Claude Sonnet 5.5 measured
Vibe Code Bench (Vals AI)92.4%37.9%Claude Sonnet 5.5
Code migration (Vals AI)69.8%27.8%Claude Sonnet 5.5
ProgramBench (Vals AI)6.5%0.0%Claude Sonnet 5.5
IOI (Vals AI)83.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench 2.1 (Vals AI)83.2%53.6%Claude Sonnet 5.5
SWE-bench Multimodal (Vals AI)58.3%Not measuredOnly Claude Sonnet 5.5 measured
CyberBench (Vals AI)59.6%Not measuredOnly Claude Sonnet 5.5 measured
SciCode61.0%51.5%Claude Sonnet 5.5
Terminal-Bench Hard (Artificial Analysis run)Not measured43.9%Only Kimi K2.6 measured
FrontierCode52.1%Not measuredOnly Claude Sonnet 5.5 measured
FrontierSWE61.9%Not measuredOnly Claude Sonnet 5.5 measured
WeirdMLNot measured55.9%Only Kimi K2.6 measured
ALE-Bench1819.11092.7Claude Sonnet 5.5
LMArena Text: coding15131489Claude Sonnet 5.5
LMArena Text: software and IT15041484Claude Sonnet 5.5
LMArena WebDev: React18171505Claude Sonnet 5.5
LMArena WebDev: HTML17411485Claude Sonnet 5.5
LMArena WebDev: from an image17371521Claude Sonnet 5.5
Neither model has a result on the other 14 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
AA Intelligence Index56.027.0Claude Sonnet 5.5
Epoch Capabilities Index166.2150.9Claude Sonnet 5.5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index71
Agentic work benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
AA Agentic IndexNot measured20.5Only Kimi K2.6 measured
Design Arena: agents building web apps13031268Claude Sonnet 5.5
Design Arena: agents building full-stack appsNot measured1155Only Kimi K2.6 measured
Design Arena: agents building mobile apps12651156Claude Sonnet 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: spreadsheets12451276Kimi K2.6
LiveBench research83.6%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench browser84.0%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench long agentic78.8%Not measuredOnly Claude Sonnet 5.5 measured
SREBench (Vals AI)30.1%Not measuredOnly Claude Sonnet 5.5 measured
Finance Agent (Vals AI)58.1%44.9%Claude Sonnet 5.5
Tax Agent Bench (Vals AI)42.0%12.4%Claude Sonnet 5.5
Legal Research Bench (Vals AI)48.1%15.9%Claude Sonnet 5.5
Harvey's Legal Agent Benchmark (Vals AI)10.4%Not measuredOnly Claude Sonnet 5.5 measured
Excel Modeling Benchmark (Vals AI)75.7%57.9%Claude Sonnet 5.5
BioMysteryBench (Vals AI)81.1%Not measuredOnly Claude Sonnet 5.5 measured
Terminal-Bench-Science (Vals AI)47.1%Not measuredOnly Claude Sonnet 5.5 measured
Vals Science Index59.1%Not measuredOnly Claude Sonnet 5.5 measured
τ²-Bench TelecomNot measured95.9%Only Kimi K2.6 measured
APEX-Agents75.5%Not measuredOnly Claude Sonnet 5.5 measured
OSWorld 2.0Not measured4.6%Only Kimi K2.6 measured
SpireClimb1.3%Not measuredOnly Claude Sonnet 5.5 measured
Vending-Bench 2$11,165$6,205Claude Sonnet 5.5
Neither model has a result on the other 12 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
Reasoning benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
GPQA DiamondNot measured89.1%Only Kimi K2.6 measured
LiveBench reasoning91.6%Not measuredOnly Claude Sonnet 5.5 measured
MysteryMechanism (Vals AI)49.1%Not measuredOnly Claude Sonnet 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)55.0%37.5%Claude Sonnet 5.5
GPQA Diamond (Epoch AI run)95.6%90.8%Claude Sonnet 5.5
Chess puzzles59.0%20.0%Claude Sonnet 5.5
Mystery game puzzles65.0%18.0%Claude Sonnet 5.5
EBR-benchNot measured2.4%Only Kimi K2.6 measured
LMArena Text: hard prompts14941470Claude Sonnet 5.5
LMArena Text: expert15311491Claude Sonnet 5.5
LMArena Text: hard prompts in English15021471Claude Sonnet 5.5
LMArena Vision: diagrams13291298Claude Sonnet 5.5
LMArena Vision: homework13311310Claude Sonnet 5.5
Neither model has a result on the other 6 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
OTIS Mock AIME100.0%96.1%Claude Sonnet 5.5
FrontierMath, tiers 1 to 388.8%57.2%Claude Sonnet 5.5
FrontierMath, tier 480.5%25.6%Claude Sonnet 5.5
ProofBench100.0%16.0%Claude Sonnet 5.5
LMArena Text: math14971474Claude Sonnet 5.5
LMArena Text: mathematical work15101480Claude 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 index60
Knowledge benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 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)52.9%40.1%Claude Sonnet 5.5
SimpleQA Verified46.5%34.9%Claude Sonnet 5.5
LMArena Text: science14831468Claude Sonnet 5.5
LMArena Text: medicine and healthcare14641457Claude Sonnet 5.5
LMArena Text: legal and government14831462Claude Sonnet 5.5
LMArena Text: business and finance14681445Claude Sonnet 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 index60
Web design benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
Design Arena: websites13261269Claude Sonnet 5.5
Design Arena: UI components13671266Claude Sonnet 5.5
Design Arena: game dev14691251Claude Sonnet 5.5
Design Arena: data viz13891249Claude Sonnet 5.5
Design Arena: 3D14581268Claude Sonnet 5.5
Design Arena: all code categories13641272Claude Sonnet 5.5
Design Arena: SVGNot measured1181Only Kimi K2.6 measured
Design Arena: ASCII artNot measured1164Only Kimi K2.6 measured
LiveBench design85.0%Not measuredOnly Claude Sonnet 5.5 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index222
General benchmarks for Claude Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 5.5Kimi K2.6Leader
Vals Index70.8%Not measuredOnly Claude Sonnet 5.5 measured
LiveBench data analysis59.5%Not measuredOnly Claude Sonnet 5.5 measured
Public Benefits Bench (Vals AI)67.2%56.6%Claude Sonnet 5.5
SAGE (Vals AI)51.8%50.2%Claude Sonnet 5.5
MedScribe (Vals AI)91.1%78.2%Claude Sonnet 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)82.7%81.0%Claude Sonnet 5.5
DTBench97.3%90.9%Claude Sonnet 5.5
LMCA68.3%37.3%Claude Sonnet 5.5
Furniture assembly75.0%21.7%Claude Sonnet 5.5
ExploitBenchNot measured18.4%Only Kimi K2.6 measured
LMArena Text14731455Claude Sonnet 5.5
LMArena Text: instruction following14921451Claude Sonnet 5.5
LMArena Text: creative writing14671434Claude Sonnet 5.5
LMArena Vision12871282Claude Sonnet 5.5
LMArena Text: English14841460Claude Sonnet 5.5
LMArena Text: non-English14561446Claude Sonnet 5.5
LMArena Text: Chinese15351520Claude Sonnet 5.5
LMArena Text: GermanNot measured1451Only Kimi K2.6 measured
LMArena Text: JapaneseNot measured1443Only Kimi K2.6 measured
LMArena Text: KoreanNot measured1427Only Kimi K2.6 measured
LMArena Text: French14991471Claude Sonnet 5.5
LMArena Text: Spanish14511464Kimi K2.6
LMArena Text: Russian14541446Claude Sonnet 5.5
LMArena Text: PolishNot measured1438Only Kimi K2.6 measured
LMArena Text: multi-turn14651453Claude Sonnet 5.5
LMArena Text: longer queries14951468Claude Sonnet 5.5
LMArena Text: writing and language14741439Claude Sonnet 5.5
LMArena Text: entertainment and media14611428Claude Sonnet 5.5
LMArena Vision: English12891287Claude Sonnet 5.5
LMArena Vision: ChineseNot measured1346Only Kimi K2.6 measured
LMArena Vision: reading text12971291Claude Sonnet 5.5
LMArena Vision: humorNot measured1280Only Kimi K2.6 measured
LMArena Vision: creative writing12421273Kimi K2.6
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 Sonnet 5.5 and Kimi K2.6
BenchmarkClaude Sonnet 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 Sonnet 5.5$0.0070Fits in one request
Kimi K2.6$0.0024Fits in one request

Kimi K2.6 costs less

Repository review

50K input + 3K output tokens

Claude Sonnet 5.5$0.130Fits in one request
Kimi K2.6$0.043Fits in one request

Kimi K2.6 costs less

Agent loop

200K input + 10K output tokens

Claude Sonnet 5.5$0.500Fits 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 Sonnet 5.5 and Kimi K2.6
SpecificationAnthropic Claude Sonnet 5.5MoonshotAI Kimi K2.6
MakerAnthropicMoonshot AI
WeightsNo public weights listedOpen weights
ReleasedSeptember 28, 2026April 20, 2026
Context window1M262K
Input $/Mtok$2.00$0.65
Output $/Mtok$10.00$3.41
Coding index88.944.2
Independent measurements behind it21
Cost per solved taskNot computable$0.35
SourceOpenRouter listingOpenRouter listing

Questions

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

Pick Claude Sonnet 5.5 for coding: it scores 88.9 on the Vibe Coding Index against 44.2 for Kimi K2.6. Pick Kimi K2.6 when output tokens cost 2.9x less, or when what matters is Design Arena: spreadsheets or LMArena Text: Spanish, where it leads.

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

Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 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 Sonnet 5.5 or Kimi K2.6?

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

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

73 benchmarks have a result for both models as of October 21, 2026. Claude Sonnet 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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