LLM Reference

Claude Sonnet 4.5 vs Kimi K2.6

Claude Sonnet 4.5 (2025) and Kimi K2.6 (2026) compare a standalone API model against a coding-specialized model. Claude Sonnet 4.5 ships a 200k-token context window, while Kimi K2.6 ships a 262k-token context window. On MMLU PRO, Claude Sonnet 4.5 leads by 1.4 pts. On pricing, Claude Sonnet 4.5 ranges from $3 to $6/1M input tokens by tier; Kimi K2.6 costs $0.73/1M input tokens. This page treats the result as workflow and deployment fit, not a universal model winner.

Treat this as a product-type comparison: Claude Sonnet 4.5 is standalone API model, while Kimi K2.6 is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.

Decision scorecard

Local evidence first
SignalClaude Sonnet 4.5Kimi K2.6
Product typeStandalone API modelCoding-specialized model
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentscustom coding agents, code generation, and tool loops
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window200k262k
Cheapest output$15/1M tokens$3.49/1M tokens
Provider routes8 tracked9 tracked
Shared benchmarksMMLU PRO leader4 shared

Decision tradeoffs

Choose Claude Sonnet 4.5 when...
  • Claude Sonnet 4.5 holds a shared-benchmark lead on MMLU PRO, ahead by 1.4 points.
  • Local decision data tags Claude Sonnet 4.5 for Coding, RAG, and Agents.
Choose Kimi K2.6 when...
  • Kimi K2.6 holds a shared-benchmark lead on SWE-bench Verified, ahead by 3 points.
  • Kimi K2.6 has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Kimi K2.6 has the lower cheapest tracked output price at $3.49/1M tokens.
  • Kimi K2.6 has broader tracked provider coverage for fallback and route flexibility.
  • Local decision data tags Kimi K2.6 for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate Kimi K2.6

Claude Sonnet 4.5

$6,150

Cheapest tracked route/tier: Microsoft Foundry

Kimi K2.6

$1,457

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $4,694. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Sonnet 4.5 -> Kimi K2.6
  • Provider overlap exists on OpenRouter, Microsoft Foundry, and Vercel AI Gateway; start route-level A/B tests there.
  • Kimi K2.6 is $11.51/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Kimi K2.6 -> Claude Sonnet 4.5
  • Provider overlap exists on Microsoft Foundry, OpenRouter, and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Sonnet 4.5 is $11.51/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.

Specs

Specification
Released2025-09-292026-04-20
Context window200k262k
Parameters—1T
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryMITOSI-approved
OpennessProprietaryOpen source
WeightsNot releasedAvailable·Moonshot Modified MIT License
CodeUnknownAvailable·Moonshot Modified MIT License
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-122025-04

Pricing and availability

Pricing attributeClaude Sonnet 4.5Kimi K2.6
Input price
0-200,001t
$3/1M tokens
200,001t+
$6/1M tokens
$0.73/1M tokens
Output price
0-200,001t
$15/1M tokens
200,001t+
$22.50/1M tokens
$3.49/1M tokens
Providers
Microsoft FoundryAnthropicSnowflake CortexGCP Vertex AIAWS BedrockReplicate API
Cloudflare Workers AINVIDIA NIMMoonshot AI KimiFireworks AIOpenRouterMicrosoft Foundry

Capabilities

CapabilityClaude Sonnet 4.5Kimi K2.6
VisionYesYes
MultimodalYesYes
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionNoNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Sonnet 4.5Kimi K2.6
MMLU PRO86.084.6
SWE-bench Verified77.280.2
Google-Proof Q&A83.490.5
MMMU Pro68.980.1

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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.