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Model comparison

Claude Sonnet 4.5 vs Kimi K2.5

Data verified

Head-to-head evidence from 9 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

53.61/100
Margin
6.0pts
winning →
Kimi K2.5
Moonshot AI
59.66/100
3 category wins2 category wins

Public leaderboard positions: Claude Sonnet 4.5 #96 (Estimated); Kimi K2.5 #54 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Sonnet 4.5 and Kimi K2.5 share 9 comparable benchmark results. 5 of 8 categories are comparable. 3 results are unique to Claude Sonnet 4.5; 54 to Kimi K2.5.

Updated July 22, 2026
Shared results
9
Claude Sonnet 4.5 only
3
Kimi K2.5 only
54
Comparable categories
5 / 8

Pick Kimi K2.5 if you want the stronger benchmark profile. Claude Sonnet 4.5 only becomes the better choice if knowledge is the priority.

Confidence note. This is a partial-evidence comparison with 9 shared benchmark results across 5 evidence categories; 5 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Kimi K2.5 is clearly ahead on the BenchAlign aggregate, 59.66 to 53.61. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Kimi K2.5's sharpest advantage is in mathematics, where it averages 60.6 against 11.2. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 13.495% to 27.900%. Claude Sonnet 4.5 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.

Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.60 input / $3.00 output per 1M tokens for Kimi K2.5. That is roughly 5.0x on output cost alone. Kimi K2.5 gives you the larger context window at 256K, compared with 200K for Claude Sonnet 4.5.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for Claude Sonnet 4.5 and Kimi K2.5
CategoryClaude Sonnet 4.5ΔKimi K2.5
MathClaude Sonnet 4.511.2Margin→ 49.4Kimi K2.560.6
ReasoningClaude Sonnet 4.513.6Margin→ 47.4Kimi K2.561.0
KnowledgeClaude Sonnet 4.583.4Margin← 26.5Kimi K2.556.9
CodingClaude Sonnet 4.577.2Margin← 17.8Kimi K2.559.4
AgenticClaude Sonnet 4.555.4Margin← 0.4Kimi K2.555.0
MultilingualClaude Sonnet 4.5Not measuredMarginNo overlapKimi K2.582.3
MultimodalClaude Sonnet 4.5Not measuredMarginNo overlapKimi K2.578.5
Inst. FollowingClaude Sonnet 4.5Not measuredMarginNo overlapKimi K2.593.9

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · Claude Sonnet 4.5B · Kimi K2.5

  1. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 13.495%B 27.900%
    Winner: Kimi K2.5Δ 14.4
    FrontierMath v2 (Tiers 1-3): Claude Sonnet 4.5 scored 13.495%; Kimi K2.5 scored 27.900%. Kimi K2.5 wins this benchmark.

  2. GPQA

    Knowledge
    Source ↗
    A 83.4%B 87.6%
    Winner: Kimi K2.5Δ 4.2
    GPQA: Claude Sonnet 4.5 scored 83.4%; Kimi K2.5 scored 87.6%. Kimi K2.5 wins this benchmark.

  3. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 50%B 50.8%
    Winner: Kimi K2.5Δ 0.8
    Terminal-Bench 2.0: Claude Sonnet 4.5 scored 50%; Kimi K2.5 scored 50.8%. Kimi K2.5 wins this benchmark.

  4. SWE-bench Verified

    Coding
    Source ↗
    A 77.2%B 76.8%
    Winner: Claude Sonnet 4.5Δ 0.4
    SWE-bench Verified: Claude Sonnet 4.5 scored 77.2%; Kimi K2.5 scored 76.8%. Claude Sonnet 4.5 wins this benchmark.

  5. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 4.167%B 4.200%
    Winner: Kimi K2.5Δ 0
    FrontierMath v2 (Tier 4): Claude Sonnet 4.5 scored 4.167%; Kimi K2.5 scored 4.200%. Kimi K2.5 wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricClaude Sonnet 4.5Kimi K2.5Comparison
Input / output priceUSD per 1M tokensClaude Sonnet 4.5$3 input / $15 outputKimi K2.5$0.6 input / $3 outputKimi K2.5 has the lower combined listed price.
Generation speedtokens per secondClaude Sonnet 4.5Not availableKimi K2.545 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Sonnet 4.5Not availableKimi K2.52.38 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Sonnet 4.5200KKimi K2.5256KKimi K2.5 lists the larger context window.

Benchmark Deep Dive

AgenticClaude Sonnet 4.5 wins
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
Terminal-Bench 2.0Source 50%50.8%Kimi K2.5 leads
OSWorld-VerifiedSource 61.4%—Not comparable
VITA-BenchSource 17.0%—Not comparable
Gert LabsSource 48.51%45.88%Claude Sonnet 4.5 leads
JobBenchSource 27.7%8.7%Claude Sonnet 4.5 leads
BrowseCompSource —60.6%Not comparable
Claw-EvalSource —52.3%Not comparable
QwenClawBenchSource —54.3%Not comparable
τ³-bench resultsSource —65.7%Not comparable
DeepSearchQASource —77.1%Not comparable
DeepPlanningSource —14.4%Not comparable
ToolathlonSource —27.8%Not comparable
MCP AtlasSource —29.5%Not comparable
MCP-TasksSource —59.1%Not comparable
WideResearchSource —72.7%Not comparable
τ²-bench resultsSource —95.9%Not comparable
APEX-Agents-AASource —11.5%Not comparable
ResearchClawBenchSource —14.0%Not comparable
AA Agentic IndexSource —21.7%Not comparable
GDPval-AASource —25.4%Not comparable
GDPval-AASource —1009Not comparable
CodingClaude Sonnet 4.5 wins
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
SWE-bench VerifiedSource 77.2%76.8%Claude Sonnet 4.5 leads
SWE-bench Verified*Source —70.8%Not comparable
LiveCodeBench v6Source —85.0%Not comparable
SWE-bench ProSource —50.7%Not comparable
SWE MultilingualSource —73%Not comparable
SWE-RebenchSource —58.5%Not comparable
React Native EvalsSource —77.2%Not comparable
SciCodeSource —48.7%Not comparable
AA-SciCodeSource —49.0%Not comparable
AA Coding IndexSource —46.8%Not comparable
ReasoningKimi K2.5 wins
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
ARC-AGI-2Source 13.6%—Not comparable
LongBench v2Source —61%Not comparable
AA-LCRSource —65.3%Not comparable
CritPtSource —3.1%Not comparable
KnowledgeClaude Sonnet 4.5 wins
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
GPQASource 83.4%87.6%Kimi K2.5 leads
GPQA-DSource —87.6%Not comparable
SuperGPQASource —69.2%Not comparable
MMLU-ProSource —87.1%Not comparable
MMLU-Pro (Arcee)Source —87.1%Not comparable
HLESource —30.1%Not comparable
Artificial Analysis Intelligence IndexSource —35.4%Not comparable
AA-GPQA DiamondSource —87.9%Not comparable
AA-HLESource —29.4%Not comparable
AA-Omniscience IndexSource —-8.1%Not comparable
AA-Omniscience AccuracySource —34.3%Not comparable
AA-Omniscience Hallucination RateSource —64.6%Not comparable
MathKimi K2.5 wins
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
AIME 2025Source 87%96.1%Kimi K2.5 leads
FrontierMath v2 (Tiers 1-3)Source 13.495%27.900%Kimi K2.5 leads
FrontierMath v2 (Tier 4)Source 4.167%4.200%Kimi K2.5 leads
AIME26Source —95.8%Not comparable
AIME25 (Arcee)Source —96.3%Not comparable
HMMT Feb 2025Source —95.4%Not comparable
HMMT Nov 2025Source —91.1%Not comparable
HMMT Feb 2026Source —87.1%Not comparable
MMAnswerBenchSource —81.8%Not comparable
Multilingual
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
MMLU-ProXSource —82.3%Not comparable
NOVA-63Source —56.0%Not comparable
Multimodal
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
Design Arena WebsiteSource 12191279Kimi K2.5 leads
MMMU-ProSource —78.5%Not comparable
Video-MMESource —87.4%Not comparable
MMVUSource —80.4%Not comparable
VideoMMMUSource —86.6%Not comparable
AA-MMMU-ProSource —75.4%Not comparable
Inst. Following
BenchmarkClaude Sonnet 4.5Kimi K2.5Result
IFEvalSource —93.9%Not comparable
AA-IFBenchSource —70.2%Not comparable
Frequently Asked Questions (6)

Which is better, Claude Sonnet 4.5 or Kimi K2.5?

Kimi K2.5 is ahead on BenchLM's BenchAlign leaderboard, 59.66 to 53.61. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 13.495% and 27.900%.

Which is better for knowledge tasks, Claude Sonnet 4.5 or Kimi K2.5?

Claude Sonnet 4.5 has the edge for knowledge tasks in this comparison, averaging 83.4 versus 56.9. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, Claude Sonnet 4.5 or Kimi K2.5?

Claude Sonnet 4.5 has the edge for coding in this comparison, averaging 77.2 versus 59.4. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Claude Sonnet 4.5 or Kimi K2.5?

Kimi K2.5 has the edge for math in this comparison, averaging 60.6 versus 11.2. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.

Which is better for reasoning, Claude Sonnet 4.5 or Kimi K2.5?

Kimi K2.5 has the edge for reasoning in this comparison, averaging 61 versus 13.6. Claude Sonnet 4.5 stays close enough that the answer can still flip depending on your workload.

Which is better for agentic tasks, Claude Sonnet 4.5 or Kimi K2.5?

Claude Sonnet 4.5 has the edge for agentic tasks in this comparison, averaging 55.4 versus 55. Inside this category, JobBench is the benchmark that creates the most daylight between them.

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
Model the full break-even

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