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Model comparison

Claude Opus 4.8 vs Kimi K2

Data verified

Head-to-head evidence from 14 shared benchmark results across 7 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

78.34/100
Margin
51.2pts
← winning
Kimi K2
Moonshot AI
27.19/100
1 category wins0 category wins

Public leaderboard positions: Claude Opus 4.8 #5 (Supported); Kimi K2 #189 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Opus 4.8 and Kimi K2 share 14 comparable benchmark results. 1 of 8 categories are comparable. 39 results are unique to Claude Opus 4.8; 0 to Kimi K2.

Updated July 23, 2026
Shared results
14
Claude Opus 4.8 only
39
Kimi K2 only
0
Comparable categories
1 / 8

Pick Claude Opus 4.8 if you want the stronger benchmark profile. Kimi K2 only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Confidence note. This is a partial-evidence comparison with 14 shared benchmark results across 7 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Claude Opus 4.8 is clearly ahead on the BenchAlign aggregate, 78.34 to 27.19. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Opus 4.8's sharpest advantage is in mathematics, where it averages 53.9 against 16.1. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 31.250% to 0.000%.

Claude Opus 4.8 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $0.60 input / $2.50 output per 1M tokens for Kimi K2. That is roughly 10.0x on output cost alone. Claude Opus 4.8 is the reasoning model in the pair, while Kimi K2 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Claude Opus 4.8 gives you the larger context window at 1M, compared with 128K for Kimi K2.

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 Opus 4.8 and Kimi K2
CategoryClaude Opus 4.8ΔKimi K2
MathClaude Opus 4.853.9Margin← 37.8Kimi K216.1
AgenticClaude Opus 4.880.3MarginNo overlapKimi K2Not measured
CodingClaude Opus 4.881.1MarginNo overlapKimi K2Not measured
KnowledgeClaude Opus 4.862.7MarginNo overlapKimi K2Not measured
MultimodalClaude Opus 4.877.0MarginNo overlapKimi K2Not measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.8B · Kimi K2

  1. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 31.250%B 0.000%
    Winner: Claude Opus 4.8Δ 31.3
    FrontierMath v2 (Tier 4): Claude Opus 4.8 scored 31.250%; Kimi K2 scored 0.000%. Claude Opus 4.8 wins this benchmark.

  2. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 47.241%B 21.404%
    Winner: Claude Opus 4.8Δ 25.8
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.8 scored 47.241%; Kimi K2 scored 21.404%. Claude Opus 4.8 wins this benchmark.

Operational comparison

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

MetricClaude Opus 4.8Kimi K2Comparison
Input / output priceUSD per 1M tokensClaude Opus 4.8$5 input / $25 outputKimi K2$0.6 input / $2.5 outputKimi K2 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.8Not availableKimi K243 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.8Not availableKimi K21.51 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.81MKimi K2128KClaude Opus 4.8 lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkClaude Opus 4.8Kimi K2Result
Terminal-Bench 2.0Source 74.6%—Not comparable
BrowseCompSource 84.3%—Not comparable
DeepSearchQASource 93.1%—Not comparable
OSWorld-VerifiedSource 83.4%—Not comparable
Finance Agent v2Source 53.9%—Not comparable
GDPval-AASource 1594—Not comparable
MCP AtlasSource 82.2%—Not comparable
ToolathlonSource 59.9%—Not comparable
Gert LabsSource 72.97%—Not comparable
AA Agentic IndexSource 47.2%—Not comparable
τ²-bench resultsSource 94.4%61.1%Claude Opus 4.8 leads
GDPval-AASource 54.7%—Not comparable
ResearchClawBenchSource 21.1%—Not comparable
OSWorld 2.0Source 20.6%—Not comparable
AA BriefcaseSource 1347—Not comparable
AA AutomationBenchSource 48.5%—Not comparable
AA EnterpriseOps-GymSource 44.0%—Not comparable
AA Harvey LABSource 91.1%—Not comparable
AA Tau3 BankingSource 27.6%—Not comparable
terminalBenchHardSource 58.3%—Not comparable
aaTerminalBench21Source 84.6%—Not comparable
Coding
BenchmarkClaude Opus 4.8Kimi K2Result
SWE-bench VerifiedSource 88.6%—Not comparable
SWE-bench ProSource 69.2%—Not comparable
SWE MultilingualSource 84.4%—Not comparable
SWE MultimodalSource 38.4%—Not comparable
Terminal-Bench 2.0Source 74.6%—Not comparable
cursorBench31Source 58.4%—Not comparable
cursorBench32Source 62.3%—Not comparable
AA Coding IndexSource 74.3%—Not comparable
AA-SciCodeSource 53.5%34.5%Claude Opus 4.8 leads
FrontierCode 1.1 MainSource 46.5%—Not comparable
Reasoning
BenchmarkClaude Opus 4.8Kimi K2Result
AA-LCRSource 67.7%51.0%Claude Opus 4.8 leads
CritPtSource 20.9%0.0%Claude Opus 4.8 leads
Knowledge
BenchmarkClaude Opus 4.8Kimi K2Result
GPQASource 93.6%—Not comparable
GPQA-DSource 93.6%—Not comparable
HLESource 57.9%—Not comparable
HLE w/o toolsSource 49.8%—Not comparable
Artificial Analysis Intelligence IndexSource 55.7%19.4%Claude Opus 4.8 leads
AA-GPQA DiamondSource 92.0%76.6%Claude Opus 4.8 leads
AA-HLESource 45.7%7.0%Claude Opus 4.8 leads
AA-Omniscience IndexSource 27.4%-27.5%Claude Opus 4.8 leads
AA-Omniscience AccuracySource 46.6%26.8%Claude Opus 4.8 leads
AA-Omniscience Hallucination RateSource 35.9%74.2%Claude Opus 4.8 leads
MathClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8Kimi K2Result
USAMO 2026Source 96.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 47.241%21.404%Claude Opus 4.8 leads
FrontierMath v2 (Tier 4)Source 31.250%0.000%Claude Opus 4.8 leads
Multilingual
BenchmarkClaude Opus 4.8Kimi K2Result
INCLUDESource 87.6%—Not comparable
Multimodal
BenchmarkClaude Opus 4.8Kimi K2Result
OfficeQA ProSource 66.2%—Not comparable
ScreenSpot ProSource 87.9%—Not comparable
CharXivSource 89.9%—Not comparable
CharXiv w/o toolsSource 80.5%—Not comparable
Design Arena WebsiteSource 12701080Claude Opus 4.8 leads
Inst. Following
BenchmarkClaude Opus 4.8Kimi K2Result
AA-IFBenchSource 62.2%41.5%Claude Opus 4.8 leads
Frequently Asked Questions (2)

Which is better, Claude Opus 4.8 or Kimi K2?

Claude Opus 4.8 is ahead on BenchLM's BenchAlign leaderboard, 78.34 to 27.19. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 31.250% and 0.000%.

Which is better for math, Claude Opus 4.8 or Kimi K2?

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 versus 16.1. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.

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