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Head-to-head comparison

Claude Sonnet 5 vs Kimi K2 Thinking

Claude Sonnet 5 (Anthropic) and Kimi K2 Thinking (Moonshot AI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 18 August 2026

As of 18 August 2026, Claude Sonnet 5 holds the stronger ModelCap Index position (#13 vs #32); Kimi K2 Thinking is 4× cheaper per output token ($2.50/1M vs $10.00/1M); and Claude Sonnet 5 offers the longer context window (1M vs 262K tokens).

Which should you choose?

Choose Claude Sonnet 5 if…

  • you want the stronger overall ModelCap Index position — #13 against #32 (73.6 vs 58.5 points).
  • you need the longer context window — 1M tokens against 262K.
  • you want provider choice — 5 listed API providers against 2.
  • Arena coding is your yardstick — 1523 against 1486.
  • Artificial Analysis Intelligence Index is your yardstick — 55.3 against 33.5.
  • you want the more recently listed model — Claude Sonnet 5 was listed 30 June 2026, Kimi K2 Thinking 6 November 2025.

Choose Kimi K2 Thinking if…

  • API cost matters — $2.50/1M output tokens against $10.00/1M, about 4× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.60/1M against $2.00/1M.

Claude Sonnet 5 vs Kimi K2 Thinking: specs, pricing and context

Specification comparison of Claude Sonnet 5 and Kimi K2 Thinking
FieldClaude Sonnet 5AnthropicKimi K2 ThinkingMoonshot AI
ModelCap Index position#13#32
Index score73.658.5
EvidenceMeasuredMeasured
Input price / 1M tokens$2.00$0.60
Output price / 1M tokens$10.00$2.50
Context window1M tokens262K tokens
Max output tokens128K100K
API providers listed52
Weight accessAPI onlyRestricted license
Input modalitiesText, Image, FileText
First listed30 June 20266 November 2025
PublisherAnthropicMoonshot AI

Evidence: 4 public benchmark observations across 4 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Claude Sonnet 5 vs Kimi K2 Thinking

Public benchmark boards where Claude Sonnet 5 or Kimi K2 Thinking has a published result
BoardClaude Sonnet 5Kimi K2 ThinkingLeads
Arena codingArena (LMArena)15231514–1531High14861481–1492TurboClaude Sonnet 5
LMArena AgentLMArena7.1%4.9%–9.4%High—Only one result
SWE-benchSWE-bench (Princeton / SWE-agent team)—63.4%ThinkingOnly one result
Artificial Analysis Intelligence IndexArtificial Analysis55.3intelligence-index33.5intelligence-indexClaude Sonnet 5

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Claude Sonnet 5 vs Kimi K2 Thinking: common questions

Is Claude Sonnet 5 better than Kimi K2 Thinking?

Claude Sonnet 5 ranks higher on the ModelCap Index as of 18 August 2026: #13 against #32. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.

Is Claude Sonnet 5 cheaper than Kimi K2 Thinking?

Kimi K2 Thinking is cheaper on output tokens: $2.50/1M against $10.00/1M. Input tokens are $2.00/1M for Claude Sonnet 5 and $0.60/1M for Kimi K2 Thinking. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Claude Sonnet 5 or Kimi K2 Thinking?

Claude Sonnet 5 has the larger context window: 1M tokens against 262K.

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

Arena coding: Claude Sonnet 5 1523, Kimi K2 Thinking 1486 — Claude Sonnet 5 leads.

Are Claude Sonnet 5 and Kimi K2 Thinking open-weight models?

Claude Sonnet 5: API only. Kimi K2 Thinking: Restricted license. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Claude Sonnet 5 and Kimi K2 Thinking?

ModelCap currently lists 5 API providers for Claude Sonnet 5 and 2 for Kimi K2 Thinking, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Sonnet 5 vs Kimi K2 Thinking comparison?

Every figure comes from the sealed ModelCap dataset published 18 August 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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