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
Claude Sonnet 5.5 vs Kimi K2
Updated November 12, 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 point estimate, 83.07 versus 33.4. Their conditional score ranges do not overlap. These ranges do not establish rank confidence. 1 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.
- API price per 1M tokens
Claude Sonnet 5.5: $2 input / $10 output
Kimi K2: $0.60 input / $2.50 output
- Context window
Claude Sonnet 5.5: 1M
Kimi K2: 128K
- Released
Claude Sonnet 5.5: September 28, 2026
Kimi K2: July 11, 2025
- Shared results
- 1
- Claude Sonnet 5.5 only
- 63
- Kimi K2 only
- 12
- Like-for-like categories
- 0 / 8
Supported: Claude Sonnet 5.5 · Estimated: Kimi K2. Conditional ranges do not establish rank confidence.How 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.
Chat turn cost
1K fresh input + 500 output tokens
Kimi K2
Kimi K2 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
Repository review cost
50K fresh input + 3K output tokens
Kimi K2
Kimi K2 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-ratesCoding work
Code generation, repair, and software-engineering tasks
Not enough matched evidence
Kimi K2 is not ranked on the public lane for coding, so no winner is named for coding.
Confidence: limitedAgentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
Kimi K2 is not ranked on the public lane for agentic, so no winner is named for agentic.
Confidence: limitedCache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Not enough matched evidence
The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. Kimi K2 does not fit this workload in one request. Kimi K2 has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback
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.
81.0Claude Sonnet 5.5—Kimi K2
Not comparable · BenchAlign v5.8
The coding row is not comparable on the public lane: at least one model is not measured or not ranked there.
Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.
Same basis rules as the category table below
Or describe your own job
The LLM Selector reads what you need a model for and returns a shortlist, ranked in the same order the job pages publish.
Describe the task and constraints. This selector recommends models; it cannot carry out the task or access your files and accounts.
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What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
63 Claude Sonnet 5.5 only
1 Shared
12 Kimi K2 only
2 categories rest 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.
SWE MultilingualCoding
Normalized gap 43.0Claude Sonnet 5.5:90.3%Kimi K2:47.3%
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 v5.8 lane for agentic, coding, reasoning, multimodal, 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.
Reasoning
Directional only- Claude Sonnet 5.5
- 77.0
- Supported · #6/160
- Kimi K2
- 28.3
- Estimated · #127/160
- Basis
- BenchAlign v5.8 lane · 0 vs 0 public rows
- Reading
- Directional only
Knowledge
Directional only- Claude Sonnet 5.5
- 82.1
- Supported · #6/180
- Kimi K2
- 35.4
- Estimated · #137/180
- Basis
- BenchAlign v5.8 lane · 17 vs 6 public rows
- Reading
- Directional only
Agentic
Not comparable- Claude Sonnet 5.5
- 72.7
- Supported · #9/135
- Kimi K2
- Not ranked
- Basis
- BenchAlign v5.8 lane · 19 vs 0 public rows
- Reading
- Not comparable
Coding
Not comparable- Claude Sonnet 5.5
- 81.0
- Supported · #4/162
- Kimi K2
- Not ranked
- Basis
- BenchAlign v5.8 lane · 12 vs 3 public rows
- Reading
- Not comparable
Multimodal
Not comparable- Claude Sonnet 5.5
- 78.9
- Estimated · #7/67
- Kimi K2
- Not ranked
- Basis
- BenchAlign v5.8 lane · 10 vs 0 public rows
- Reading
- Not comparable
Multilingual
Not comparable- Claude Sonnet 5.5
- Not ranked
- Kimi K2
- 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
- 48.4
- #103/157
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Math
Not comparable- Claude Sonnet 5.5
- 89.7
- Unranked · 4 rankable rows
- Kimi K2
- 0.0
- #12/12
- Basis
- Provisional lane · 2 vs 0 weighted rows
- Reading
- Not comparable
| Category | Claude Sonnet 5.5 | Kimi K2 | Basis | Reading |
|---|---|---|---|---|
| Reasoning | 77.0Supported · #6/160 | 28.3Estimated · #127/160 | Directional onlyBenchAlign v5.8 lane · 0 vs 0 public rows | Directional only |
| Knowledge | 82.1Supported · #6/180 | 35.4Estimated · #137/180 | Directional onlyBenchAlign v5.8 lane · 17 vs 6 public rows | Directional only |
| Agentic | 72.7Supported · #9/135 | Not ranked | Not comparableBenchAlign v5.8 lane · 19 vs 0 public rows | Not comparable |
| Coding | 81.0Supported · #4/162 | Not ranked | Not comparableBenchAlign v5.8 lane · 12 vs 3 public rows | Not comparable |
| Multimodal | 78.9Estimated · #7/67 | Not ranked | Not comparableBenchAlign v5.8 lane · 10 vs 0 public rows | Not comparable |
| Multilingual | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Instruction following | Not ranked | 48.4#103/157 | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Math | 89.7Unranked · 4 rankable rows | 0.0#12/12 | Not comparableProvisional lane · 2 vs 0 weighted rows | Not comparable |
Ranks count the models scored in each category’s lane, so the agentic, coding, reasoning, multimodal, and knowledge denominators (BenchAlign v5.8) 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
- $0.00185
- Fits in one request
Kimi K2 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
- $0.0375
- Fits in one request
Kimi K2 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
- $0.16
- Fits in one request
- Kimi K2
- $0.157
- Does not fit in one request
- Cached input priced at the published list-input rate
Kimi K2 does not fit this workload in one request. Kimi K2 has no published cached-input rate, so cached tokens use its listed input rate.
Your workload
Enter a month of tokens to price it at both models’ listed API rates.
- Claude Sonnet 5.5
- $40.00
- per month
- Kimi K2
- $11.00
- per month
Standard listed rates, no batch or volume discounts.
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.
SpecificationClaude Sonnet 5.5Kimi K2
Context window
Maximum documented context; output-token limits may be lower.
Claude Sonnet 5.5
Kimi K2
128K
API model ID
Claude Sonnet 5.5
claude-sonnet-5-5
Anthropic Claude Sonnet 5.5 model documentationKimi K2
Not sourced
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
$0.1 per 1M cached input tokens
Claude API pricingKimi K2
Not published
Documented inputs
Claude Sonnet 5.5
Kimi K2
Documented outputs
Claude Sonnet 5.5
Kimi K2
Provider availability
Claude Sonnet 5.5
Generally Available · Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry, Claude Platform on AWS
Anthropic Claude Sonnet 5.5 model documentationKimi K2
Not sourced
Reasoning profile
Claude Sonnet 5.5
Reasoning
Kimi K2
Non-Reasoning
Weight access
Claude Sonnet 5.5
Proprietary
Kimi K2
Proprietary
License
Claude Sonnet 5.5
Proprietary
Kimi K2
Proprietary
Release date
Claude Sonnet 5.5
2026-09-28
Kimi K2
2025-07-11
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 point estimate, 83.07 versus 33.4. Their conditional score ranges do not overlap. These ranges do not establish rank confidence.
- Workload cost
- Repository review: $0.13 vs $0.0375. Cache-heavy agent loop: $0.16 vs $0.157.
- 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?
Claude Sonnet 5.5 has the higher public point estimate, 83.07 versus 33.4. Their conditional score ranges do not overlap. These ranges do not establish rank confidence. The page therefore keeps the decision tied to the specific documented workload.
Which is better for coding, Claude Sonnet 5.5 or Kimi K2?
Kimi K2 is not ranked on the public lane for coding, so no winner is named for coding.
Which is better for agentic tasks, Claude Sonnet 5.5 or Kimi K2?
Kimi K2 is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.
Which costs less, Claude Sonnet 5.5 or Kimi K2?
For the stated presets, chat costs $0.007 on Claude Sonnet 5.5 and $0.00185 on Kimi K2; repository review costs $0.13 and $0.0375; the cache-heavy agent loop costs $0.16 and $0.157. Kimi K2 does not fit this workload in one request. Kimi K2 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, Claude Sonnet 5.5 or Kimi K2?
Claude Sonnet 5.5 has the larger documented context window: 1M, compared with 128K.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence76 rows
Agentic
Terminal-Bench 4.1
Claude Sonnet 5.563.90%SourceKimi K2—Not directly comparable
Terminal-Bench 4.0
Claude Sonnet 5.570.60%SourceKimi K2—Not directly comparable
HLE w/ tools
Claude Sonnet 5.564.5%SourceKimi K2—Not directly comparable
DRACO
Claude Sonnet 5.587.0%SourceKimi K2—Not directly comparable
Terminal-Bench-Science 0.1
Claude Sonnet 5.559.9%SourceKimi K2—Not directly comparable
LAB all-pass (Harvey held-out)
Claude Sonnet 5.510.0%SourceKimi K2—Not directly comparable
LAB criterion-pass (Harvey held-out)
Claude Sonnet 5.593.1%SourceKimi K2—Not directly comparable
Toolathlon Verified Pass@3
Claude Sonnet 5.585.2%SourceKimi K2—Not directly comparable
Toolathlon Verified Pass³
Claude Sonnet 5.568.5%SourceKimi K2—Not directly comparable
Toolathlon Verified avg. turns
Claude Sonnet 5.531.6 turnsSourceKimi K2—Not directly comparable
AutomationBench (Zapier 1.0.6)
Claude Sonnet 5.544.70%SourceKimi K2—Not directly comparable
Toolathlon-Verified
Claude Sonnet 5.577.8%SourceKimi K2—Not directly comparable
Hermes Index
Claude Sonnet 5.553.1%SourceKimi K2—Not directly comparable
Hermes Bench
Claude Sonnet 5.573.5%SourceKimi K2—Not directly comparable
MazeBench
Claude Sonnet 5.58%SourceKimi K2—Not directly comparable
OSWorld 2.1
Claude Sonnet 5.580.1%SourceKimi K2—Not directly comparable
OSWorld 2.1 Offline
Claude Sonnet 5.583.9%SourceKimi K2—Not directly comparable
Binary Exploitation Benchmark
Claude Sonnet 5.548SourceKimi K2—Not directly comparable
Terminal-Bench 2.1 (Vals)
Claude Sonnet 5.583.1%SourceKimi K2—Not directly comparable
Coding
FrontierCode 1.1 Main
Claude Sonnet 5.546.2%SourceKimi K2—Not directly comparable
CursorBench 4.0
Claude Sonnet 5.555.5%SourceKimi K2—Not directly comparable
SWE-bench Pro
Claude Sonnet 5.581.3%SourceKimi K2—Not directly comparable
SWE Multilingual
Claude Sonnet 5.590.3%SourceKimi K247.3%SourceClaude Sonnet 5.5 leads this result
SWE Multimodal
Claude Sonnet 5.554.3%SourceKimi K2—Not directly comparable
DeepSWE
Claude Sonnet 5.571.0%SourceKimi K2—Not directly comparable
FrontierCode 1.1 Extended
Claude Sonnet 5.559.1%SourceKimi K2—Not directly comparable
ProgramBench
Claude Sonnet 5.579.7%SourceKimi K2—Not directly comparable
FrontierSWE v2
Claude Sonnet 5.561.9%SourceKimi K2—Not directly comparable
Bug Hunt Bench
Claude Sonnet 5.551.3 fixesSourceKimi K2—Not directly comparable
FrontierCode 2.0
Claude Sonnet 5.541.0%SourceKimi K2—Not directly comparable
VulcanBench Frontier v4
Claude Sonnet 5.592.0%SourceKimi K2—Not directly comparable
SWE-bench Verified
Claude Sonnet 5.5—Kimi K265.8%SourceNot directly comparable
LiveCodeBench v6
Claude Sonnet 5.5—Kimi K253.7%SourceNot directly comparable
Multimodal
ExtractBench Pro
Claude Sonnet 5.532%SourceKimi K2—Not directly comparable
ExtractBench (LlamaIndex)
Claude Sonnet 5.594.68%SourceKimi K2—Not directly comparable
ParseBench
Claude Sonnet 5.569.21%SourceKimi K2—Not directly comparable
Chartography (no tools)
Claude Sonnet 5.561.6%SourceKimi K2—Not directly comparable
Chartography (tools)
Claude Sonnet 5.590.2%SourceKimi K2—Not directly comparable
BenchCAD Vision2Code (no tools)
Claude Sonnet 5.50.747SourceKimi K2—Not directly comparable
BenchCAD Vision2Code (tools)
Claude Sonnet 5.50.963SourceKimi K2—Not directly comparable
Biomedical image analysis
Claude Sonnet 5.572.2%SourceKimi K2—Not directly comparable
OfficeQA
Claude Sonnet 5.576.9%SourceKimi K2—Not directly comparable
OfficeQA Pro
Claude Sonnet 5.565.6%SourceKimi K2—Not directly comparable
Knowledge
HealthBench (raw)
Claude Sonnet 5.569.4%SourceKimi K2—Not directly comparable
HealthBench (length-adjusted)
Claude Sonnet 5.565.4%SourceKimi K2—Not directly comparable
HealthBench Professional (raw)
Claude Sonnet 5.577.1%SourceKimi K2—Not directly comparable
HealthBench Professional
Claude Sonnet 5.569.2%SourceKimi K2—Not directly comparable
BioMysteryBench (human-solvable)
Claude Sonnet 5.589.2%SourceKimi K2—Not directly comparable
BioMysteryBench (human-difficult)
Claude Sonnet 5.544.7%SourceKimi K2—Not directly comparable
SpatialBench Verified
Claude Sonnet 5.572.5%SourceKimi K2—Not directly comparable
SingleCellBench
Claude Sonnet 5.559.1%SourceKimi K2—Not directly comparable
Protein Design
Claude Sonnet 5.551.0%SourceKimi K2—Not directly comparable
Morphology-to-molecule matching
Claude Sonnet 5.525.0%SourceKimi K2—Not directly comparable
Medicinal chemistry
Claude Sonnet 5.565.3%SourceKimi K2—Not directly comparable
Protein Design library ranking
Claude Sonnet 5.554.8%SourceKimi K2—Not directly comparable
De novo protein-binder design
Claude Sonnet 5.582.3%SourceKimi K2—Not directly comparable
Protocols (troubleshooting)
Claude Sonnet 5.567.3%SourceKimi K2—Not directly comparable
Protocols (understanding)
Claude Sonnet 5.566.6%SourceKimi K2—Not directly comparable
HLE w/o tools
Claude Sonnet 5.556.9%SourceKimi K2—Not directly comparable
PhysicianBench
Claude Sonnet 5.563.2%SourceKimi K2—Not directly comparable
MMLU
Claude Sonnet 5.5—Kimi K289.5%SourceNot directly comparable
GPQA
Claude Sonnet 5.5—Kimi K275.1%SourceNot directly comparable
SuperGPQA
Claude Sonnet 5.5—Kimi K257.2%SourceNot directly comparable
MMLU-Pro
Claude Sonnet 5.5—Kimi K281.1%SourceNot directly comparable
SimpleQA
Claude Sonnet 5.5—Kimi K231%SourceNot directly comparable
HLE
Claude Sonnet 5.5—Kimi K24.7%SourceNot directly comparable
Multilingual
Instruction following
IFEval
Claude Sonnet 5.5—Kimi K289.8%SourceNot directly comparable
Math
ArXivMath Aug. 2026 (no tools)
Claude Sonnet 5.586.8%SourceKimi K2—Not directly comparable
ArXivMath Aug. 2026 (tools)
Claude Sonnet 5.595.2%SourceKimi K2—Not directly comparable
FrontierMath v2 (Tiers 1-3)
Claude Sonnet 5.588.772%SourceKimi K2—Not directly comparable
FrontierMath v2 (Tier 4)
Claude Sonnet 5.580.488%SourceKimi K2—Not directly comparable
AIME 2024
Claude Sonnet 5.5—Kimi K269.6%SourceNot directly comparable
AIME 2025
Claude Sonnet 5.5—Kimi K249.5%SourceNot directly comparable
MATH-500
Claude Sonnet 5.5—Kimi K297.4%SourceNot directly comparable
76 public results · 1 shared
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Last updated November 12, 2026