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BenchLM

Claude Sonnet 5.5 vs Kimi K2.6

Updated September 28, 2026. Rank says Claude Sonnet 5.5 is ahead. Price, access, and your workload can each overturn that. Public scores include evidence status and uncertainty.

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Decision reading

Claude Sonnet 5.5 has the higher public score, 80.49 versus 59.22, and the 90% score intervals do not overlap. 2 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

Model A
Anthropic logo

Anthropic

80.49/100

Estimated · Public rank #5

90% interval 69.0–92.0

Model B
Moonshot AI logo

Moonshot AI

59.22/100

Estimated · Public rank #47

90% interval 51.9–66.6

Shared results
2
Claude Sonnet 5.5 only
45
Kimi K2.6 only
35
Like-for-like categories
2 / 8
Estimated: Claude Sonnet 5.5 and Kimi K2.6How the comparison works

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Agentic work

    Tool use, computer use, and multi-step task completion

    Claude Sonnet 5.5

    Claude Sonnet 5.5 leads on the public agentic lane, 66.1 to 43.7, with Supported evidence for both models and non-overlapping 90% intervals.

    Confidence: stronger
  • Long documents

    Prompts that approach the documented context limit

    Claude Sonnet 5.5

    Claude Sonnet 5.5 has the larger documented context window.

    Confidence: documented
  • Chat turn cost

    1K fresh input + 500 output tokens

    Kimi K2.6

    Kimi K2.6 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
Show secondary and unsupported calls
  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Kimi K2.6

    Kimi K2.6 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
  • Repository review cost

    50K fresh input + 3K output tokens

    Kimi K2.6

    Kimi K2.6 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates
  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    Claude Sonnet 5.5 is scored on Estimated evidence for coding, so the reading is directional rather than like-for-like.

    Confidence: limited

Which one for a specific job

Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.

The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.

79.6Claude Sonnet 5.546.2Kimi K2.6

Directional only · BenchAlign v5.7

Claude Sonnet 5.5 scores higher, but at least one score rests on Estimated evidence or a different benchmark set. Directional only, no winner.

Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.

Same basis rules as the category table below

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

1 category rests on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.

Bars run 0–100 on each benchmark’s normalized display scale

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign v5.7 lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Agentic

Like-for-like
Claude Sonnet 5.5
66.1
Supported · #10/111
Kimi K2.6
43.7
Supported · #41/111
Basis
BenchAlign v5.7 lane · 11 vs 12 public rows
Reading
Claude Sonnet 5.5 leads

Knowledge

Like-for-like
Claude Sonnet 5.5
80.9
Supported · #6/160
Kimi K2.6
59.1
Supported · #37/160
Basis
BenchAlign v5.7 lane · 16 vs 5 public rows
Reading
Claude Sonnet 5.5 leads

Coding

Directional only
Claude Sonnet 5.5
79.6
Estimated · #3/136
Kimi K2.6
46.2
Supported · #44/136
Basis
BenchAlign v5.7 lane · 9 vs 10 public rows
Reading
Directional only

Reasoning

Not comparable
Claude Sonnet 5.5
79.2
#7/27
Kimi K2.6
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multimodal

Not comparable
Claude Sonnet 5.5
83.3
Unranked · 7 rankable rows
Kimi K2.6
64.9
#27/50
Basis
Provisional lane · 1 vs 2 weighted rows
Reading
Not comparable

Multilingual

Not comparable
Claude Sonnet 5.5
Not ranked
Kimi K2.6
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
Claude Sonnet 5.5
Not ranked
Kimi K2.6
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Math

Not comparable
Claude Sonnet 5.5
Not ranked
Kimi K2.6
71.0
#1/7
Basis
Provisional lane · 0 vs 4 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign v5.7) differ from the provisional-lane categories. Unranked scores sit on the provisional lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Supported evidence per lane · bars run 0–100Methodology

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

Claude Sonnet 5.5
$0.007
Fits in one request
Kimi K2.6
$0.00295
Fits in one request

Kimi K2.6 has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

Claude Sonnet 5.5
$0.13
Fits in one request
Kimi K2.6
$0.0595
Fits in one request

Kimi K2.6 has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

Claude Sonnet 5.5
$0.18
Fits in one request
Kimi K2.6
$0.091
Fits in one request

Kimi K2.6 has the lower modeled cost

Costs use the listed standard API rates.

Cached input falls back to the list input rate only where a cached rate is unpublished

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

Claude Sonnet 5.5

$0.2 per 1M cached input tokens

Claude API pricing

Kimi K2.6

$0.16 per 1M cached input tokens

Reasoning profile

Claude Sonnet 5.5

Reasoning

Kimi K2.6

Reasoning

Weight access

Claude Sonnet 5.5

Proprietary

Kimi K2.6

Open Weight

License

Claude Sonnet 5.5

Proprietary

Kimi K2.6

Open Weight

Release date

Claude Sonnet 5.5

2026-09-28

Kimi K2.6

2026-04-20

If you already use one of these models

Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
Claude Sonnet 5.5 has the higher public score, 80.49 versus 59.22, and the 90% score intervals do not overlap.
Workload cost
Repository review: $0.13 vs $0.0595. Cache-heavy agent loop: $0.18 vs $0.091.
Context tradeoff
Claude Sonnet 5.5 has the larger documented window (1M).
Run the same representative tasks against both endpoints before changing production traffic.

Questions

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

Claude Sonnet 5.5 has the higher public score, 80.49 versus 59.22, and the 90% score intervals do not overlap. That is the clearest overall quality signal in the current public data.

Which is better for coding, Claude Sonnet 5.5 or Kimi K2.6?

Claude Sonnet 5.5 scores higher for coding on the public lane, 79.6 to 46.2. Claude Sonnet 5.5 is scored on Estimated evidence for coding, so the reading is directional rather than like-for-like. BenchLM does not name a winner for coding from a directional reading; read the shared benchmark rows directly and test the models on the same task set.

Which is better for agentic tasks, Claude Sonnet 5.5 or Kimi K2.6?

Claude Sonnet 5.5 leads the public agentic tasks lane, 66.1 to 43.7, with Supported evidence for both models and non-overlapping 90% intervals.

Which costs less, Claude Sonnet 5.5 or Kimi K2.6?

For the stated presets, chat costs $0.007 on Claude Sonnet 5.5 and $0.00295 on Kimi K2.6; repository review costs $0.13 and $0.0595; the cache-heavy agent loop costs $0.18 and $0.091. Costs use the listed standard API rates.

Which has the larger context window, Claude Sonnet 5.5 or Kimi K2.6?

Claude Sonnet 5.5 has the larger documented context window: 1M, compared with 256K.

Self-host vs API cost

Estimates at 50,000 req/day · 1000 tokens/req average.

Claude Sonnet 5.5
API / mo$9,000
Self-host / moNot listed
Break-even—
Proprietary model — self-hosting not applicable.
Kimi K2.6
API / mo$3,713
Self-host / mo$18,221
Break-even326M/day
Model the full break-even

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence82 rows

Agentic

  • Terminal-Bench 4.0

    Claude Sonnet 5.570.60%
    Source
    Kimi K2.6—

    Not directly comparable

  • HLE w/ tools

    Claude Sonnet 5.564.5%
    Source
    Kimi K2.6—

    Not directly comparable

  • DRACO

    Claude Sonnet 5.587.0%
    Source
    Kimi K2.6—

    Not directly comparable

  • Terminal-Bench-Science 0.1

    Claude Sonnet 5.559.9%
    Source
    Kimi K2.6—

    Not directly comparable

  • LAB all-pass (Harvey held-out)

    Claude Sonnet 5.510.0%
    Source
    Kimi K2.6—

    Not directly comparable

  • LAB criterion-pass (Harvey held-out)

    Claude Sonnet 5.593.1%
    Source
    Kimi K2.6—

    Not directly comparable

  • Toolathlon Verified Pass@3

    Claude Sonnet 5.585.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • Toolathlon Verified Pass³

    Claude Sonnet 5.568.5%
    Source
    Kimi K2.6—

    Not directly comparable

  • Toolathlon Verified avg. turns

    Claude Sonnet 5.531.6 turns
    Source
    Kimi K2.6—

    Not directly comparable

  • AutomationBench (Zapier 1.0.6)

    Claude Sonnet 5.544.7%
    Source
    Kimi K2.6—

    Not directly comparable

  • Toolathlon-Verified

    Claude Sonnet 5.577.8%
    Source
    Kimi K2.6—

    Not directly comparable

  • Terminal-Bench 2.0

    Claude Sonnet 5.5—
    Kimi K2.666.7%
    Source

    Not directly comparable

  • BrowseComp

    Claude Sonnet 5.5—
    Kimi K2.683.2%
    Source

    Not directly comparable

  • OSWorld-Verified

    Claude Sonnet 5.5—
    Kimi K2.673.1%
    Source

    Not directly comparable

  • Toolathlon

    Claude Sonnet 5.5—
    Kimi K2.650%
    Source

    Not directly comparable

  • MCP Atlas

    Claude Sonnet 5.5—
    Kimi K2.655.9%
    Source

    Not directly comparable

  • Claw-Eval

    Claude Sonnet 5.5—
    Kimi K2.662.3%
    Source

    Not directly comparable

  • DeepSearchQA

    Claude Sonnet 5.5—
    Kimi K2.692.5%
    Source

    Not directly comparable

  • WideResearch

    Claude Sonnet 5.5—
    Kimi K2.680.8%
    Source

    Not directly comparable

  • Gert Labs

    Claude Sonnet 5.5—
    Kimi K2.656.82%
    Source

    Not directly comparable

  • ResearchClawBench

    Claude Sonnet 5.5—
    Kimi K2.618.0%
    Source

    Not directly comparable

  • OSWorld 2.0

    Claude Sonnet 5.5—
    Kimi K2.64.6%
    Source

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    Claude Sonnet 5.5—
    Kimi K2.653.6%
    Source

    Not directly comparable

Coding

  • FrontierCode 1.1 Main

    Claude Sonnet 5.546.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • cursorBench40

    Claude Sonnet 5.555.5%
    Source
    Kimi K2.6—

    Not directly comparable

  • SWE-bench Pro

    Claude Sonnet 5.581.3%
    Source
    Kimi K2.658.6%
    Source

    Claude Sonnet 5.5 leads this result

  • SWE Multilingual

    Claude Sonnet 5.590.3%
    Source
    Kimi K2.676.7%
    Source

    Claude Sonnet 5.5 leads this result

  • SWE Multimodal

    Claude Sonnet 5.554.3%
    Source
    Kimi K2.6—

    Not directly comparable

  • DeepSWE

    Claude Sonnet 5.571.0%
    Source
    Kimi K2.6—

    Not directly comparable

  • FrontierCode 1.1 Extended

    Claude Sonnet 5.559.1%
    Source
    Kimi K2.6—

    Not directly comparable

  • ProgramBench

    Claude Sonnet 5.579.7%
    Source
    Kimi K2.6—

    Not directly comparable

  • FrontierSWE v2

    Claude Sonnet 5.561.9%
    Source
    Kimi K2.6—

    Not directly comparable

  • SWE-bench Verified

    Claude Sonnet 5.5—
    Kimi K2.680.2%
    Source

    Not directly comparable

  • LiveCodeBench v6

    Claude Sonnet 5.5—
    Kimi K2.689.6%
    Source

    Not directly comparable

  • SciCode

    Claude Sonnet 5.5—
    Kimi K2.652.2%
    Source

    Not directly comparable

  • Terminal-Bench 2.0

    Claude Sonnet 5.5—
    Kimi K2.666.7%
    Source

    Not directly comparable

  • Vibe Code Bench

    Claude Sonnet 5.5—
    Kimi K2.637.89%
    Source

    Not directly comparable

  • cursorBench31

    Claude Sonnet 5.5—
    Kimi K2.647.6%
    Source

    Not directly comparable

  • LiveCodeBench (Vals)

    Claude Sonnet 5.5—
    Kimi K2.686.8%
    Source

    Not directly comparable

  • SWE-bench (Vals)

    Claude Sonnet 5.5—
    Kimi K2.676.2%
    Source

    Not directly comparable

Multimodal

  • Chartography (no tools)

    Claude Sonnet 5.561.6%
    Source
    Kimi K2.6—

    Not directly comparable

  • Chartography (tools)

    Claude Sonnet 5.590.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • BenchCAD Vision2Code (no tools)

    Claude Sonnet 5.50.747
    Source
    Kimi K2.6—

    Not directly comparable

  • BenchCAD Vision2Code (tools)

    Claude Sonnet 5.50.963
    Source
    Kimi K2.6—

    Not directly comparable

  • Biomedical image analysis

    Claude Sonnet 5.572.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • OfficeQA

    Claude Sonnet 5.576.9%
    Source
    Kimi K2.6—

    Not directly comparable

  • OfficeQA Pro

    Claude Sonnet 5.565.6%
    Source
    Kimi K2.6—

    Not directly comparable

  • MMMU-Pro

    Claude Sonnet 5.5—
    Kimi K2.679.4%
    Source

    Not directly comparable

  • MMMU-Pro w/ Python

    Claude Sonnet 5.5—
    Kimi K2.680.1%
    Source

    Not directly comparable

  • CharXiv

    Claude Sonnet 5.5—
    Kimi K2.680.4%
    Source

    Not directly comparable

  • MathVision

    Claude Sonnet 5.5—
    Kimi K2.687.4%
    Source

    Not directly comparable

  • V*

    Claude Sonnet 5.5—
    Kimi K2.696.9%
    Source

    Not directly comparable

Knowledge

  • HealthBench (raw)

    Claude Sonnet 5.569.4%
    Source
    Kimi K2.6—

    Not directly comparable

  • HealthBench (length-adjusted)

    Claude Sonnet 5.565.4%
    Source
    Kimi K2.6—

    Not directly comparable

  • HealthBench Professional (raw)

    Claude Sonnet 5.577.1%
    Source
    Kimi K2.6—

    Not directly comparable

  • HealthBench Professional

    Claude Sonnet 5.569.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • BioMysteryBench (human-solvable)

    Claude Sonnet 5.589.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • BioMysteryBench (human-difficult)

    Claude Sonnet 5.544.7%
    Source
    Kimi K2.6—

    Not directly comparable

  • SpatialBench Verified

    Claude Sonnet 5.572.5%
    Source
    Kimi K2.6—

    Not directly comparable

  • SingleCellBench

    Claude Sonnet 5.559.1%
    Source
    Kimi K2.6—

    Not directly comparable

  • Protein Design

    Claude Sonnet 5.551.0%
    Source
    Kimi K2.6—

    Not directly comparable

  • Morphology-to-molecule matching

    Claude Sonnet 5.525.0%
    Source
    Kimi K2.6—

    Not directly comparable

  • Medicinal chemistry

    Claude Sonnet 5.565.3%
    Source
    Kimi K2.6—

    Not directly comparable

  • Protein Design library ranking

    Claude Sonnet 5.554.8%
    Source
    Kimi K2.6—

    Not directly comparable

  • De novo protein-binder design

    Claude Sonnet 5.582.3%
    Source
    Kimi K2.6—

    Not directly comparable

  • Protocols (troubleshooting)

    Claude Sonnet 5.567.3%
    Source
    Kimi K2.6—

    Not directly comparable

  • Protocols (understanding)

    Claude Sonnet 5.566.6%
    Source
    Kimi K2.6—

    Not directly comparable

  • HLE w/o tools

    Claude Sonnet 5.556.9%
    Source
    Kimi K2.6—

    Not directly comparable

  • GPQA

    Claude Sonnet 5.5—
    Kimi K2.690.5%
    Source

    Not directly comparable

  • GPQA-D

    Claude Sonnet 5.5—
    Kimi K2.690.5%
    Source

    Not directly comparable

  • HLE

    Claude Sonnet 5.5—
    Kimi K2.634.7%
    Source

    Not directly comparable

  • GPQA Diamond (Vals)

    Claude Sonnet 5.5—
    Kimi K2.689.1%
    Source

    Not directly comparable

  • MMLU-Pro (Vals)

    Claude Sonnet 5.5—
    Kimi K2.687.6%
    Source

    Not directly comparable

Multilingual

  • GMMLU

    Claude Sonnet 5.592.1%
    Source
    Kimi K2.6—

    Not directly comparable

  • MILU

    Claude Sonnet 5.591.6%
    Source
    Kimi K2.6—

    Not directly comparable

Math

  • ArXivMath Aug. 2026 (no tools)

    Claude Sonnet 5.586.8%
    Source
    Kimi K2.6—

    Not directly comparable

  • ArXivMath Aug. 2026 (tools)

    Claude Sonnet 5.595.2%
    Source
    Kimi K2.6—

    Not directly comparable

  • AIME26

    Claude Sonnet 5.5—
    Kimi K2.696.4%
    Source

    Not directly comparable

  • HMMT Feb 2026

    Claude Sonnet 5.5—
    Kimi K2.692.7%
    Source

    Not directly comparable

  • MMAnswerBench

    Claude Sonnet 5.5—
    Kimi K2.686.0%
    Source

    Not directly comparable

  • FrontierMath v2 (Tiers 1-3)

    Claude Sonnet 5.5—
    Kimi K2.638.966%
    Source

    Not directly comparable

  • FrontierMath v2 (Tier 4)

    Claude Sonnet 5.5—
    Kimi K2.614.580%
    Source

    Not directly comparable

82 public results · 2 shared

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Last updated September 28, 2026