Noometry

Model comparison

Claude Sonnet 5 vs Kimi K2 (Jul 2025)

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 41.2 on the Noometry Index. Kimi K2 (Jul 2025) costs 4.0× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.

Last verified . 24 shared benchmarks.

Claude Sonnet 5 Anthropic

54.6

Rank #29 Confirmed

Kimi K2 (Jul 2025) Moonshot AI

41.2

Rank #140 Confirmed

Summary

  • They share 24 benchmarks with published results for both. Claude Sonnet 5 scores higher in 9 categories and Kimi K2 (Jul 2025) in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Sonnet 5 leads 49.1 to 23.3.
  • The biggest single-benchmark swing is SimpleBench: 60.6% for Claude Sonnet 5 and 26.3% for Kimi K2 (Jul 2025).
  • Kimi K2 (Jul 2025) is cheaper at $0.57 / $2.30 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.
  • Claude Sonnet 5 accepts more context: 1M tokens versus 262K.
  • Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 5Kimi K2 (Jul 2025)
ProviderAnthropicMoonshot AI
Noometry Index54.641.2
Released2026-06-292025-07-12
WeightsProprietaryOpen
Context window1M262K
Max output128K262K
Input $ / M tokens$2$0.57
Output $ / M tokens$10$2.30
Results tracked5142

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Category by category

Coding Claude Sonnet 5 leads

Claude Sonnet 5: 55.5 (#26), Kimi K2 (Jul 2025): 42.4 (#102)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
GSO37.3%4.9%
WeirdML68.8%42.8%
LMArena Coding14831399
ALE-Bench1,463597.5
DeepSWE53.8%—
FrontierCode42.7%—
SWE-bench Verified (bash only)—63.4%
Aider Polyglot—59.1%
CursorBench34.1%—
LMArena WebDev1541—
SciCode54.3%—

Agentic & Tool Use Claude Sonnet 5 leads

Claude Sonnet 5: 42.8 (#18), Kimi K2 (Jul 2025): 32.4 (#64)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
Terminal-Bench—35.7%
APEX-Agents54.5%—
Berkeley Function Calling Leaderboard—59.1%
GBAEval65.3%—
LMArena Search1194—
METR Time Horizons—59.2%
Vending-Bench 26,378—

Reasoning Claude Sonnet 5 leads

Claude Sonnet 5: 49.1 (#39), Kimi K2 (Jul 2025): 23.3 (#179)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
SimpleBench60.6%26.3%
LMArena Hard Prompts14611384
Epoch Capabilities Index156.21146.01
ForecastBench61.160.2
Kagi LLM Benchmark—64.4%
NYT Connections (extended)75.1%—
CritPt16.9%—
Chess Puzzles35%—
Mystery Game Puzzles35%—
DTBench92.5%—
LMCA50%—
Surface Evolver Bench60%—
Bench to the Future 30.14—

Math Claude Sonnet 5 leads

Claude Sonnet 5: 66.2 (#27), Kimi K2 (Jul 2025): 42.7 (#83)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Math14671397
FrontierMath (Tiers 1-3)65.6%—
FrontierMath Tier 429.3%—
OTIS Mock AIME 2024-202594.7%—
ProofBench77%—
Omni-MATH—65.4%
FrontierMath (Feb 2025 set)—21.4%
FrontierMath Tier 4 (v1)—0%

Knowledge Claude Sonnet 5 leads

Claude Sonnet 5: 55.6 (#47), Kimi K2 (Jul 2025): 37.3 (#157)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Expert14901365
GPQA Diamond90.5%—
SimpleQA Verified33.7%—
MMLU-Pro—81.9%
Confabulations—20.4%
Vectara Hallucination Rate—17.9%
GPQA (HELM)—65.3%

Multimodal Not comparable

Claude Sonnet 5: 42.4 (#31), Kimi K2 (Jul 2025): —

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Vision1274—
Blueprint-Bench 224.9%—
LMArena Document1466—

Multilingual Claude Sonnet 5 leads

Claude Sonnet 5: 53.8 (#55), Kimi K2 (Jul 2025): 49.6 (#130)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Non-English14311372
LMArena Chinese14771415
LMArena French14601379
LMArena German14401387
LMArena Japanese14221349
LMArena Korean14111325
LMArena Russian14511385
LMArena Spanish14371386

Instruction Following Claude Sonnet 5 leads

Claude Sonnet 5: 76.3 (#41), Kimi K2 (Jul 2025): 71.1 (#156)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Instruction Following14521348
IFEval—85%

Long Context Claude Sonnet 5 leads

Claude Sonnet 5: 44.8 (#55), Kimi K2 (Jul 2025): 41.2 (#145)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Longer Query14631353
Fiction.LiveBench—66.7%
CL-bench—17.6%

Writing & Preference Claude Sonnet 5 leads

Claude Sonnet 5: 69.2 (#25), Kimi K2 (Jul 2025): 62.3 (#78)

BenchmarkClaude Sonnet 5Kimi K2 (Jul 2025)
LMArena Text14421380
LMArena Creative Writing14161350
EQ-Bench Creative Writing17941666
LMArena Multi-Turn14541371
Short-Story Creative Writing—85.6%
WildBench—86.2%
EQ-Bench 41236—

Frequently asked questions

Is Claude Sonnet 5 better than Kimi K2 (Jul 2025)?

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 41.2 on the Noometry Index. Kimi K2 (Jul 2025) costs 4.0× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.

Which is cheaper, Claude Sonnet 5 or Kimi K2 (Jul 2025)?

Kimi K2 (Jul 2025) is cheaper. It lists at $0.57 per million input tokens and $2.30 per million output tokens; Claude Sonnet 5 lists at $2 and $10.

Is Claude Sonnet 5 or Kimi K2 (Jul 2025) better for coding?

Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 42.4 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 5 does, with 1M tokens against 262K.

How many benchmarks do Claude Sonnet 5 and Kimi K2 (Jul 2025) share?

24 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and Kimi K2 (Jul 2025) has 42.

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