Long documents
Prompts that approach the documented context limit
Kimi K2.5
Kimi K2.5 has the larger documented context window.
Confidence: documented
Claude Sonnet 4.5 vs Kimi K2.5
Updated September 29, 2026. Rank says Kimi K2.5 is ahead. Price, access, and your workload can each overturn that. Public scores include evidence status and uncertainty.
Both of these models will change. Get the price, version and retirement notices for the pair, each with its source. Follow model changes
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Decision reading
Kimi K2.5 has the higher public score estimate, 52.85 versus 47.85, but the 90% score intervals overlap. Treat that as a lead, not a settled winner. 8 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.
- Shared results
- 8
- Claude Sonnet 4.5 only
- 3
- Kimi K2.5 only
- 37
- Like-for-like categories
- 0 / 8
Estimated: Claude Sonnet 4.5 · Supported: Kimi K2.5How 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 K2.5
Kimi K2.5 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 K2.5
Kimi K2.5 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
Claude Sonnet 4.5 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
Claude Sonnet 4.5 and Kimi K2.5 are scored on Estimated evidence for agentic, so the reading is directional rather than like-for-like.
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. Claude Sonnet 4.5 does not fit this workload in one request. Claude Sonnet 4.5 has no published cached-input rate, so cached tokens use its listed input rate. Kimi K2.5 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.
—Claude Sonnet 4.538.8Kimi K2.5
Not comparable · BenchAlign v5.7
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
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
3 Claude Sonnet 4.5 only
8 Shared
37 Kimi K2.5 only
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.
FrontierMath v2 (Tiers 1-3)Math
Normalized gap 14.4Claude Sonnet 4.5:13.495%Kimi K2.5:27.900%GPQAKnowledge
Normalized gap 4.2Claude Sonnet 4.5:83.4%Kimi K2.5:87.6%Terminal-Bench 2.0Agentic
Normalized gap 0.8Claude Sonnet 4.5:50%Kimi K2.5:50.8%SWE-bench VerifiedCoding
Normalized gap 0.4Claude Sonnet 4.5:77.2%Kimi K2.5:76.8%FrontierMath v2 (Tier 4)Math
Normalized gap 0.0Claude Sonnet 4.5:4.167%Kimi K2.5:4.200%
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
Directional only- Claude Sonnet 4.5
- 34.6
- Estimated · #67/117
- Kimi K2.5
- 36.5
- Estimated · #61/117
- Basis
- BenchAlign v5.7 lane · 5 vs 14 public rows
- Reading
- Directional only
Coding
Not comparable- Claude Sonnet 4.5
- Not ranked
- Kimi K2.5
- 38.8
- Estimated · #66/143
- Basis
- BenchAlign v5.7 lane · 1 vs 8 public rows
- Reading
- Not comparable
Reasoning
Not comparable- Claude Sonnet 4.5
- 19.2
- Unranked · 1 rankable row
- Kimi K2.5
- 55.2
- Unranked · 3 rankable rows
- Basis
- Provisional lane · 1 vs 1 weighted rows
- Reading
- Not comparable
Multimodal
Not comparable- Claude Sonnet 4.5
- Not ranked
- Kimi K2.5
- 66.8
- #25/50
- Basis
- Provisional lane · 0 vs 1 weighted rows
- Reading
- Not comparable
Knowledge
Not comparable- Claude Sonnet 4.5
- Not ranked
- Kimi K2.5
- 47.8
- Estimated · #71/169
- Basis
- BenchAlign v5.7 lane · 1 vs 6 public rows
- Reading
- Not comparable
Multilingual
Not comparable- Claude Sonnet 4.5
- Not ranked
- Kimi K2.5
- 38.2
- #8/12
- Basis
- Provisional lane · 0 vs 1 weighted rows
- Reading
- Not comparable
Instruction following
Not comparable- Claude Sonnet 4.5
- Not ranked
- Kimi K2.5
- 84.4
- #41/124
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Math
Not comparable- Claude Sonnet 4.5
- 34.6
- Unranked · 2 rankable rows
- Kimi K2.5
- 62.1
- #4/7
- Basis
- Provisional lane · 2 vs 4 weighted rows
- Reading
- Not comparable
| Category | Claude Sonnet 4.5 | Kimi K2.5 | Basis | Reading |
|---|---|---|---|---|
| Agentic | 34.6Estimated · #67/117 | 36.5Estimated · #61/117 | Directional onlyBenchAlign v5.7 lane · 5 vs 14 public rows | Directional only |
| Coding | Not ranked | 38.8Estimated · #66/143 | Not comparableBenchAlign v5.7 lane · 1 vs 8 public rows | Not comparable |
| Reasoning | 19.2Unranked · 1 rankable row | 55.2Unranked · 3 rankable rows | Not comparableProvisional lane · 1 vs 1 weighted rows | Not comparable |
| Multimodal | Not ranked | 66.8#25/50 | Not comparableProvisional lane · 0 vs 1 weighted rows | Not comparable |
| Knowledge | Not ranked | 47.8Estimated · #71/169 | Not comparableBenchAlign v5.7 lane · 1 vs 6 public rows | Not comparable |
| Multilingual | Not ranked | 38.2#8/12 | Not comparableProvisional lane · 0 vs 1 weighted rows | Not comparable |
| Instruction following | Not ranked | 84.4#41/124 | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Math | 34.6Unranked · 2 rankable rows | 62.1#4/7 | Not comparableProvisional lane · 2 vs 4 weighted rows | 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.
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 4.5
- $0.0105
- Fits in one request
- Kimi K2.5
- $0.0021
- Fits in one request
Kimi K2.5 has the lower modeled cost
Costs use the listed standard API rates.
Repository review
50K fresh input + 3K output tokens
- Claude Sonnet 4.5
- $0.195
- Fits in one request
- Kimi K2.5
- $0.039
- Fits in one request
Kimi K2.5 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 4.5
- $0.81
- Does not fit in one request
- Cached input priced at the published list-input rate
- Kimi K2.5
- $0.162
- Fits in one request
- Cached input priced at the published list-input rate
Claude Sonnet 4.5 does not fit this workload in one request. Claude Sonnet 4.5 has no published cached-input rate, so cached tokens use its listed input rate. Kimi K2.5 has no published cached-input rate, so cached tokens use its listed input rate.
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 4.5Kimi K2.5
Context window
Maximum documented context; output-token limits may be lower.
Claude Sonnet 4.5
200K
Kimi K2.5
256K
API model ID
Claude Sonnet 4.5
Not sourced
Kimi K2.5
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 4.5
Not published
Kimi K2.5
Not published
Documented inputs
Claude Sonnet 4.5
Not sourced
Kimi K2.5
Not sourced
Documented outputs
Claude Sonnet 4.5
Not sourced
Kimi K2.5
Not sourced
Provider availability
Claude Sonnet 4.5
Not sourced
Kimi K2.5
Not sourced
Reasoning profile
Claude Sonnet 4.5
Non-Reasoning
Kimi K2.5
Non-Reasoning
Weight access
Claude Sonnet 4.5
Proprietary
Kimi K2.5
Open Weight
License
Claude Sonnet 4.5
Proprietary
Kimi K2.5
Open Weight
Release date
Claude Sonnet 4.5
2025-09-01
Kimi K2.5
2026-02-01
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
- Kimi K2.5 has the higher public score estimate, 52.85 versus 47.85, but the 90% score intervals overlap.
- Workload cost
- Repository review: $0.195 vs $0.039. Cache-heavy agent loop: $0.81 vs $0.162.
- Context tradeoff
- Kimi K2.5 has the larger documented window (256K).
Run the same representative tasks against both endpoints before changing production traffic.
Questions
Which is better, Claude Sonnet 4.5 or Kimi K2.5?
Kimi K2.5 has the higher public score estimate, 52.85 versus 47.85, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.
Which is better for coding, Claude Sonnet 4.5 or Kimi K2.5?
Claude Sonnet 4.5 is not ranked on the public lane for coding, so no winner is named for coding.
Which is better for agentic tasks, Claude Sonnet 4.5 or Kimi K2.5?
Kimi K2.5 scores higher for agentic tasks on the public lane, 36.5 to 34.6. Claude Sonnet 4.5 and Kimi K2.5 are scored on Estimated evidence for agentic tasks, so the reading is directional rather than like-for-like. BenchLM does not name a winner for agentic tasks from a directional reading; read the shared benchmark rows directly and test the models on the same task set.
Which costs less, Claude Sonnet 4.5 or Kimi K2.5?
For the stated presets, chat costs $0.0105 on Claude Sonnet 4.5 and $0.0021 on Kimi K2.5; repository review costs $0.195 and $0.039; the cache-heavy agent loop costs $0.81 and $0.162. Claude Sonnet 4.5 does not fit this workload in one request. Claude Sonnet 4.5 has no published cached-input rate, so cached tokens use its listed input rate. Kimi K2.5 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, Claude Sonnet 4.5 or Kimi K2.5?
Kimi K2.5 has the larger documented context window: 256K, compared with 200K.
Self-host vs API cost
Estimates at 50,000 req/day · 1000 tokens/req average.
Claude Sonnet 4.5
API / mo$13,500
Self-host / moNot listed
Break-even—
Proprietary model — self-hosting not applicable.
Kimi K2.5
API / mo$2,700
Self-host / mo$5,221
Break-even132M/day
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence48 rows
Agentic
Terminal-Bench 2.0
Claude Sonnet 4.550%SourceKimi K2.550.8%SourceKimi K2.5 leads this result
OSWorld-Verified
Claude Sonnet 4.561.4%SourceKimi K2.5—Not directly comparable
VITA-Bench
Claude Sonnet 4.517.0%SourceKimi K2.5—Not directly comparable
Gert Labs
Shared sourceClaude Sonnet 4.548.51%Kimi K2.545.88%Claude Sonnet 4.5 leads this result
JobBench
Shared sourceClaude Sonnet 4.527.7%Kimi K2.58.7%Claude Sonnet 4.5 leads this result
BrowseComp
Claude Sonnet 4.5—Kimi K2.560.6%SourceNot directly comparable
Claw-Eval
Claude Sonnet 4.5—Kimi K2.552.3%SourceNot directly comparable
QwenClawBench
Claude Sonnet 4.5—Kimi K2.554.3%SourceNot directly comparable
τ³-bench results
Claude Sonnet 4.5—Kimi K2.565.7%SourceNot directly comparable
DeepSearchQA
Claude Sonnet 4.5—Kimi K2.577.1%SourceNot directly comparable
DeepPlanning
Claude Sonnet 4.5—Kimi K2.514.4%SourceNot directly comparable
Toolathlon
Claude Sonnet 4.5—Kimi K2.527.8%SourceNot directly comparable
MCP Atlas
Claude Sonnet 4.5—Kimi K2.529.5%SourceNot directly comparable
MCP-Tasks
Claude Sonnet 4.5—Kimi K2.559.1%SourceNot directly comparable
WideResearch
Claude Sonnet 4.5—Kimi K2.572.7%SourceNot directly comparable
ResearchClawBench
Claude Sonnet 4.5—Kimi K2.514.0%SourceNot directly comparable
Coding
SWE-bench Verified
Claude Sonnet 4.577.2%SourceKimi K2.576.8%SourceClaude Sonnet 4.5 leads this result
SWE-bench Verified*
Claude Sonnet 4.5—Kimi K2.570.8%SourceNot directly comparable
LiveCodeBench v6
Claude Sonnet 4.5—Kimi K2.585.0%SourceNot directly comparable
SWE-bench Pro
Claude Sonnet 4.5—Kimi K2.550.7%SourceNot directly comparable
SWE Multilingual
Claude Sonnet 4.5—Kimi K2.573%SourceNot directly comparable
SWE-Rebench
Claude Sonnet 4.5—Kimi K2.558.5%SourceNot directly comparable
React Native Evals
Claude Sonnet 4.5—Kimi K2.577.2%SourceNot directly comparable
SciCode
Claude Sonnet 4.5—Kimi K2.548.7%SourceNot directly comparable
Reasoning
Multimodal
Knowledge
GPQA
Claude Sonnet 4.583.4%SourceKimi K2.587.6%SourceKimi K2.5 leads this result
GPQA-D
Claude Sonnet 4.5—Kimi K2.587.6%SourceNot directly comparable
SuperGPQA
Claude Sonnet 4.5—Kimi K2.569.2%SourceNot directly comparable
MMLU-Pro
Claude Sonnet 4.5—Kimi K2.587.1%SourceNot directly comparable
MMLU-Pro (Arcee)
Claude Sonnet 4.5—Kimi K2.587.1%SourceNot directly comparable
HLE
Claude Sonnet 4.5—Kimi K2.530.1%SourceNot directly comparable
Multilingual
Instruction following
IFEval
Claude Sonnet 4.5—Kimi K2.593.9%SourceNot directly comparable
Math
AIME 2025
Claude Sonnet 4.587%SourceKimi K2.596.1%SourceKimi K2.5 leads this result
FrontierMath v2 (Tiers 1-3)
Shared sourceClaude Sonnet 4.513.495%Kimi K2.527.900%Kimi K2.5 leads this result
FrontierMath v2 (Tier 4)
Shared sourceClaude Sonnet 4.54.167%Kimi K2.54.200%Kimi K2.5 leads this result
AIME26
Claude Sonnet 4.5—Kimi K2.595.8%SourceNot directly comparable
AIME25 (Arcee)
Claude Sonnet 4.5—Kimi K2.596.3%SourceNot directly comparable
HMMT Feb 2025
Claude Sonnet 4.5—Kimi K2.595.4%SourceNot directly comparable
HMMT Nov 2025
Claude Sonnet 4.5—Kimi K2.591.1%SourceNot directly comparable
HMMT Feb 2026
Claude Sonnet 4.5—Kimi K2.587.1%SourceNot directly comparable
MMAnswerBench
Claude Sonnet 4.5—Kimi K2.581.8%SourceNot directly comparable
48 public results · 8 shared
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Last updated September 29, 2026